ci: run ci with v1.96.0 beta release

https://rust-lang.github.io/rust-clippy/master/index.html#manual_clear

.cirrus.yml

@@ -1,58 +0,0 @@
-only_if: $CIRRUS_TAG == '' && ($CIRRUS_PR != '' || $CIRRUS_BRANCH == 'master' || $CIRRUS_BRANCH =~ 'tokio-.*')
-auto_cancellation: $CIRRUS_BRANCH != 'master' && $CIRRUS_BRANCH !=~ 'tokio-.*'
-freebsd_instance:
-  image_family: freebsd-14-2
-env:
-  RUST_STABLE: stable
-  RUST_NIGHTLY: nightly-2025-01-25
-  RUSTFLAGS: -D warnings
-
-# Test FreeBSD in a full VM on cirrus-ci.com.  Test the i686 target too, in the
-# same VM.  The binary will be built in 32-bit mode, but will execute on a
-# 64-bit kernel and in a 64-bit environment.  Our tests don't execute any of
-# the system's binaries, so the environment shouldn't matter.
-task:
-  name: FreeBSD 64-bit
-  setup_script:
-    - pkg install -y bash
-    - curl https://sh.rustup.rs -sSf --output rustup.sh
-    - sh rustup.sh -y --profile minimal --default-toolchain $RUST_STABLE
-    - . $HOME/.cargo/env
-    - |
-      echo "~~~~ rustc --version ~~~~"
-      rustc --version
-  test_script:
-    - . $HOME/.cargo/env
-    - cargo test --all --all-features
-
-task:
-  name: FreeBSD docs
-  env:
-    RUSTFLAGS: --cfg docsrs --cfg tokio_unstable
-    RUSTDOCFLAGS: --cfg docsrs --cfg tokio_unstable -Dwarnings
-  setup_script:
-    - pkg install -y bash
-    - curl https://sh.rustup.rs -sSf --output rustup.sh
-    - sh rustup.sh -y --profile minimal --default-toolchain $RUST_NIGHTLY
-    - . $HOME/.cargo/env
-    - |
-      echo "~~~~ rustc --version ~~~~"
-      rustc --version
-  test_script:
-    - . $HOME/.cargo/env
-    - cargo doc --lib --no-deps --all-features --document-private-items
-
-task:
-  name: FreeBSD 32-bit
-  setup_script:
-    - pkg install -y bash
-    - curl https://sh.rustup.rs -sSf --output rustup.sh
-    - sh rustup.sh -y --profile minimal --default-toolchain $RUST_STABLE
-    - . $HOME/.cargo/env
-    - rustup target add i686-unknown-freebsd
-    - |
-      echo "~~~~ rustc --version ~~~~"
-      rustc --version
-  test_script:
-    - . $HOME/.cargo/env
-    - cargo test --all --all-features --target i686-unknown-freebsd

.github/dependabot.yml

@@ -0,0 +1,7 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    open-pull-requests-limit: 10

.github/labeler.yml

@@ -1,28 +1,40 @@
+R-loom-blocking:
+- changed-files:
+  - any-glob-to-any-file:
+    - tokio/src/runtime/blocking/*
+    - tokio/src/runtime/blocking/**/*
 
 R-loom-sync:
-- tokio/src/sync/*
-- tokio/src/sync/**/*
+- changed-files:
+  - any-glob-to-any-file:
+    - tokio/src/sync/*
+    - tokio/src/sync/**/*
 
 R-loom-time-driver:
-- tokio/src/runtime/time/*
-- tokio/src/runtime/time/**/*
+- changed-files:
+  - any-glob-to-any-file:
+    - tokio/src/runtime/time/*
+    - tokio/src/runtime/time/**/*
 
 R-loom-current-thread:
-- tokio/src/runtime/scheduler/*
-- tokio/src/runtime/scheduler/current_thread/*
-- tokio/src/runtime/task/*
-- tokio/src/runtime/task/**
+- changed-files:
+  - any-glob-to-any-file:
+    - tokio/src/runtime/scheduler/*
+    - tokio/src/runtime/scheduler/current_thread/*
+    - tokio/src/runtime/task/*
+    - tokio/src/runtime/task/**
 
 R-loom-multi-thread:
-- tokio/src/runtime/scheduler/*
-- tokio/src/runtime/scheduler/multi_thread/*
-- tokio/src/runtime/scheduler/multi_thread/**
-- tokio/src/runtime/task/*
-- tokio/src/runtime/task/**
+- changed-files:
+  - any-glob-to-any-file:
+    - tokio/src/runtime/scheduler/*
+    - tokio/src/runtime/scheduler/multi_thread/*
+    - tokio/src/runtime/scheduler/multi_thread/**
+    - tokio/src/runtime/task/*
+    - tokio/src/runtime/task/**
 
-R-loom-multi-thread-alt:
-- tokio/src/runtime/scheduler/*
-- tokio/src/runtime/scheduler/multi_thread_alt/*
-- tokio/src/runtime/scheduler/multi_thread_alt/**
-- tokio/src/runtime/task/*
-- tokio/src/runtime/task/**
+R-loom-util:
+- changed-files:
+  - any-glob-to-any-file:
+    - tokio-util/src/*
+    - tokio-util/src/**/*

.github/workflows/audit.yml

@@ -20,5 +20,5 @@ jobs:
       issues: write
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - uses: EmbarkStudios/cargo-deny-action@v2

.github/workflows/labeler.yml

@@ -19,7 +19,7 @@ jobs:
     runs-on: ubuntu-latest
     if: github.repository_owner == 'tokio-rs'
     steps:
-    - uses: actions/labeler@v3
+    - uses: actions/labeler@v6
       with:
         repo-token: "${{ secrets.GITHUB_TOKEN }}"
         sync-labels: true

.github/workflows/loom.yml

@@ -23,13 +23,29 @@ permissions:
   contents: read
 
 jobs:
+  loom-blocking:
+    name: loom tokio::runtime::spawn_blocking
+    # base_ref is null when it's not a pull request
+    if: github.repository_owner == 'tokio-rs' && (contains(github.event.pull_request.labels.*.name, 'R-loom-blocking') || (github.base_ref == null))
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - name: Install Rust ${{ env.rust_stable }}
+        uses: dtolnay/rust-toolchain@master
+        with:
+            toolchain: ${{ env.rust_stable }}
+      - uses: Swatinem/rust-cache@v2
+      - name: run tests
+        run: cargo test --lib --release --features full -- --nocapture loom_blocking
+        working-directory: tokio
+
   loom-sync:
     name: loom tokio::sync
     # base_ref is null when it's not a pull request
     if: github.repository_owner == 'tokio-rs' && (contains(github.event.pull_request.labels.*.name, 'R-loom-sync') || (github.base_ref == null))
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Install Rust ${{ env.rust_stable }}
         uses: dtolnay/rust-toolchain@master
         with:
@@ -45,14 +61,14 @@ jobs:
     if: github.repository_owner == 'tokio-rs' && (contains(github.event.pull_request.labels.*.name, 'R-loom-time-driver') || (github.base_ref == null))
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Install Rust ${{ env.rust_stable }}
         uses: dtolnay/rust-toolchain@master
         with:
             toolchain: ${{ env.rust_stable }}
       - uses: Swatinem/rust-cache@v2
       - name: run tests
-        run: cargo test --lib --release --features full -- --nocapture runtime::time::tests
+        run: cargo test --lib --release --features full -- --nocapture runtime::time
         working-directory: tokio
 
   loom-current-thread:
@@ -61,7 +77,7 @@ jobs:
     if: github.repository_owner == 'tokio-rs' && (contains(github.event.pull_request.labels.*.name, 'R-loom-current-thread') || (github.base_ref == null))
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Install Rust ${{ env.rust_stable }}
         uses: dtolnay/rust-toolchain@master
         with:
@@ -84,7 +100,7 @@ jobs:
           - scope: loom_multi_thread::group_c
           - scope: loom_multi_thread::group_d
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Install Rust ${{ env.rust_stable }}
         uses: dtolnay/rust-toolchain@master
         with:
@@ -96,27 +112,18 @@ jobs:
         env:
           SCOPE: ${{ matrix.scope }}
 
-  loom-multi-thread-alt:
-    name: loom ALT multi-thread scheduler
+  loom-util:
+    name: loom tokio-util
     # base_ref is null when it's not a pull request
-    if: github.repository_owner == 'tokio-rs' && (contains(github.event.pull_request.labels.*.name, 'R-loom-multi-thread-alt') || (github.base_ref == null))
+    if: github.repository_owner == 'tokio-rs' && (contains(github.event.pull_request.labels.*.name, 'R-loom-util') || (github.base_ref == null))
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        include:
-          - scope: loom_multi_thread_alt::group_a
-          - scope: loom_multi_thread_alt::group_b
-          - scope: loom_multi_thread_alt::group_c
-          - scope: loom_multi_thread_alt::group_d
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Install Rust ${{ env.rust_stable }}
         uses: dtolnay/rust-toolchain@master
         with:
             toolchain: ${{ env.rust_stable }}
       - uses: Swatinem/rust-cache@v2
-      - name: loom ${{ matrix.scope }}
-        run: cargo test --lib --release --features full -- --nocapture $SCOPE
-        working-directory: tokio
-        env:
-          SCOPE: ${{ matrix.scope }}
+      - name: run tests
+        run: cargo test --lib --release --features full -- --nocapture
+        working-directory: tokio-util

.github/workflows/pr-audit.yml

@@ -19,5 +19,5 @@ jobs:
   cargo-deny:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - uses: EmbarkStudios/cargo-deny-action@v2

.github/workflows/stress-test.yml

@@ -27,7 +27,7 @@ jobs:
         stress-test:
           - simple_echo_tcp
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Install Rust ${{ env.rust_stable }}
         uses: dtolnay/rust-toolchain@master
         with:

.github/workflows/uring-kernel-version-test.yml

@@ -0,0 +1,105 @@
+name: Uring Kernel Version Test
+
+on:
+  workflow_call:
+    inputs:
+      kernel_version:
+        description: 'Version of the Linux kernel to build'
+        required: true
+        type: string
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    env:
+      KERNEL_VERSION: ${{ inputs.kernel_version }}
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Install system dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y \
+            build-essential bison flex libssl-dev libelf-dev \
+            qemu-system-x86 busybox-static cpio xz-utils wget
+
+      - name: Cache Linux source
+        id: cache-kernel
+        uses: actions/cache@v5
+        with:
+          path: linux-${{ env.KERNEL_VERSION }}
+          key: kernel-${{ env.KERNEL_VERSION }}
+
+      - name: Download & build Linux kernel
+        if: steps.cache-kernel.outputs.cache-hit != 'true'
+        run: |
+          MAJOR=${KERNEL_VERSION%%.*}
+          wget https://cdn.kernel.org/pub/linux/kernel/v${MAJOR}.x/linux-${KERNEL_VERSION}.tar.xz
+          tar xf linux-${KERNEL_VERSION}.tar.xz
+          cd linux-${KERNEL_VERSION}
+          make defconfig
+          make -j$(nproc)
+
+      # We are running tests also on a Kernel version that does not support io_uring
+      # to check if the fallback mechanism works
+      - name: Generate test binaries with io_uring enabled
+        run: |
+          # Build both integration (tokio/tests/) and unit (e.g., tokio/src/fs/file/tests.rs) tests with io_uring enabled
+          rustup target add x86_64-unknown-linux-musl
+          RUSTFLAGS="--cfg tokio_unstable" \
+            cargo test -p tokio --features full,io-uring \
+            --target x86_64-unknown-linux-musl --test 'fs*' --lib --no-run
+
+      - name: Prepare initramfs + tests binaries
+        run: |
+          set -e
+          rm -rf initramfs
+          mkdir -p initramfs/{bin,bin/tests,sbin,proc,sys,tmp}
+
+          # Copy test binaries into initramfs
+          for bin in target/x86_64-unknown-linux-musl/debug/deps/{fs_*,tokio-*}; do
+            if [ -f "$bin" ] && [ -x "$bin" ]; then
+              cp "$bin" initramfs/bin/tests
+            fi
+          done
+
+          # Add BusyBox & symlinks
+          cp /usr/bin/busybox initramfs/bin/
+          for cmd in sh mount uname true sleep; do ln -sf busybox initramfs/bin/$cmd; done
+          ln -sf ../bin/busybox initramfs/sbin/poweroff
+
+          # Generate init script
+          cat > initramfs/init << 'EOF'
+          #!/bin/sh
+          set -e
+          mkdir -p /dev
+          # create device nodes, as some tests require them
+          mknod /dev/null c 1 3
+          mknod /dev/zero c 1 5
+          mknod /dev/tty c 5 0
+          mount -t proc proc /proc
+          mount -t sysfs sysfs /sys
+          mkdir -p /tmp && mount -t tmpfs -o mode=1777 tmpfs /tmp
+          for f in /bin/tests/*; do RUST_BACKTRACE=1 "$f" ; done
+          EOF
+          chmod +x initramfs/init
+
+          # Pack into a CPIO archive
+          (cd initramfs && find . -print0 \
+            | cpio --null -ov --format=newc | gzip -9 > ../initramfs.cpio.gz)
+
+      - name: Run tests in QEMU
+        run: |
+          qemu-system-x86_64 \
+            -kernel linux-${{ env.KERNEL_VERSION }}/arch/x86/boot/bzImage \
+            -initrd initramfs.cpio.gz \
+            -append "console=ttyS0 rootfstype=ramfs panic=1" \
+            -nographic -no-reboot -m 1024 -action panic=exit-failure 2>&1 | tee qemu-output.log
+
+          # qemu always exits with 0, so we check if the tests passed by using grep.
+          if grep -q "test result: FAILED" qemu-output.log; then
+            echo "tests failed (QEMU exited abnormally)"
+            exit 1
+          else
+            echo "all tests passed"
+          fi

.gitignore

@@ -3,3 +3,4 @@ Cargo.lock
 
 .cargo/config.toml
 .cargo/config
+

CONTRIBUTING.md

@@ -1,7 +1,6 @@
 # Contributing to Tokio
 
-:balloon: Thanks for your help improving the project! We are so happy to have
-you!
+Thanks for your help improving Tokio! We are so happy to have you!
 
 There are opportunities to contribute to Tokio at any level. It doesn't matter if
 you are just getting started with Rust or are the most weathered expert, we can
@@ -9,15 +8,11 @@ use your help.
 
 **No contribution is too small and all contributions are valued.**
 
-This guide will help you get started. **Do not let this guide intimidate you**.
-It should be considered a map to help you navigate the process.
+See the [contributing guidelines] to get started.
 
-The [dev channel][dev] is available for any concerns not covered in this guide, please join
-us!
+[contributing guidelines]: docs/contributing/README.md
 
-[dev]: https://discord.gg/tokio
-
-## Conduct
+## Code of Conduct
 
 The Tokio project adheres to the [Rust Code of Conduct][coc]. This describes
 the _minimum_ behavior expected from all contributors. Instances of violations of the
@@ -26,709 +21,34 @@ Code of Conduct can be reported by contacting the project team at
 
 [coc]: https://github.com/rust-lang/rust/blob/master/CODE_OF_CONDUCT.md
 
-## Contributing in Issues
+## Need Help?
 
-For any issue, there are fundamentally three ways an individual can contribute:
+Reach out to us on the [Discord server] for any concern not covered in this guide.
 
-1. By opening the issue for discussion: For instance, if you believe that you
-   have discovered a bug in Tokio, creating a new issue in [the tokio-rs/tokio
-   issue tracker][issue] is the way to report it.
-
-2. By helping to triage the issue: This can be done by providing
-   supporting details (a test case that demonstrates a bug), providing
-   suggestions on how to address the issue, or ensuring that the issue is tagged
-   correctly.
-
-3. By helping to resolve the issue: Typically this is done either in the form of
-   demonstrating that the issue reported is not a problem after all, or more
-   often, by opening a Pull Request that changes some bit of something in
-   Tokio in a concrete and reviewable manner.
-
-[issue]: https://github.com/tokio-rs/tokio/issues
-
-**Anybody can participate in any stage of contribution**. We urge you to
-participate in the discussion around bugs and participate in reviewing PRs.
-
-### Asking for General Help
-
-If you have reviewed existing documentation and still have questions or are
-having problems, you can [open a discussion] asking for help.
-
-In exchange for receiving help, we ask that you contribute back a documentation
-PR that helps others avoid the problems that you encountered.
-
-[open a discussion]: https://github.com/tokio-rs/tokio/discussions/new
-
-### Submitting a Bug Report
-
-When opening a new issue in the Tokio issue tracker, you will be presented
-with a basic template that should be filled in. If you believe that you have
-uncovered a bug, please fill out this form, following the template to the best
-of your ability. Do not worry if you cannot answer every detail, just fill in
-what you can.
-
-The two most important pieces of information we need in order to properly
-evaluate the report is a description of the behavior you are seeing and a simple
-test case we can use to recreate the problem on our own. If we cannot recreate
-the issue, it becomes impossible for us to fix.
-
-In order to rule out the possibility of bugs introduced by userland code, test
-cases should be limited, as much as possible, to using only Tokio APIs.
-
-See [How to create a Minimal, Complete, and Verifiable example][mcve].
-
-[mcve]: https://stackoverflow.com/help/mcve
-
-### Triaging a Bug Report
-
-Once an issue has been opened, it is not uncommon for there to be discussion
-around it. Some contributors may have differing opinions about the issue,
-including whether the behavior being seen is a bug or a feature. This discussion
-is part of the process and should be kept focused, helpful, and professional.
-
-Short, clipped responses—that provide neither additional context nor supporting
-detail—are not helpful or professional. To many, such responses are simply
-annoying and unfriendly.
-
-Contributors are encouraged to help one another make forward progress as much as
-possible, empowering one another to solve issues collaboratively. If you choose
-to comment on an issue that you feel either is not a problem that needs to be
-fixed, or if you encounter information in an issue that you feel is incorrect,
-explain why you feel that way with additional supporting context, and be willing
-to be convinced that you may be wrong. By doing so, we can often reach the
-correct outcome much faster.
-
-### Resolving a Bug Report
-
-In the majority of cases, issues are resolved by opening a Pull Request. The
-process for opening and reviewing a Pull Request is similar to that of opening
-and triaging issues, but carries with it a necessary review and approval
-workflow that ensures that the proposed changes meet the minimal quality and
-functional guidelines of the Tokio project.
-
-## Pull Requests
-
-Pull Requests are the way concrete changes are made to the code, documentation,
-and dependencies in the Tokio repository.
-
-Even tiny pull requests (e.g., one character pull request fixing a typo in API
-documentation) are greatly appreciated. Before making a large change, it is
-usually a good idea to first open an issue describing the change to solicit
-feedback and guidance. This will increase the likelihood of the PR getting
-merged.
-
-### Cargo Commands
-
-Due to the extensive use of features in Tokio, you will often need to add extra
-arguments to many common cargo commands. This section lists some commonly needed
-commands.
-
-Some commands just need the `--all-features` argument:
-
-```
-cargo build --all-features
-cargo check --all-features
-cargo test --all-features
-```
-
-Ideally, you should use the same version of clippy as the one used in CI
-(defined by `env.rust_clippy` in [ci.yml][ci.yml]), because newer versions
-might have new lints:
-
-[ci.yml]: .github/workflows/ci.yml
-
-<!--
-When updating this, also update:
-- .github/workflows/ci.yml
-- README.md
-- tokio/README.md
-- tokio/Cargo.toml
-- tokio-util/Cargo.toml
-- tokio-test/Cargo.toml
-- tokio-stream/Cargo.toml
--->
-
-```
-cargo +1.77 clippy --all --tests --all-features
-```
-
-When building documentation, a simple `cargo doc` is not sufficient. To produce
-documentation equivalent to what will be produced in docs.rs's builds of Tokio's
-docs, please use:
-
-```
-RUSTDOCFLAGS="--cfg docsrs --cfg tokio_unstable" RUSTFLAGS="--cfg docsrs --cfg tokio_unstable" cargo +nightly doc --all-features [--open]
-```
-
-This turns on indicators to display the Cargo features required for
-conditionally compiled APIs in Tokio, and it enables documentation of unstable
-Tokio features. Notice that it is necessary to pass cfg flags to both RustDoc
-*and* rustc.
-
-There is a more concise way to build docs.rs-equivalent docs by using [`cargo
-docs-rs`], which reads the above documentation flags out of Tokio's Cargo.toml
-as docs.rs itself does.
-
-[`cargo docs-rs`]: https://github.com/dtolnay/cargo-docs-rs
-
-```
-cargo install --locked cargo-docs-rs
-cargo +nightly docs-rs [--open]
-```
-
-The `cargo fmt` command does not work on the Tokio codebase. You can use the
-command below instead:
-
-```
-# Mac or Linux
-rustfmt --check --edition 2021 $(git ls-files '*.rs')
-
-# Powershell
-Get-ChildItem . -Filter "*.rs" -Recurse | foreach { rustfmt --check --edition 2021 $_.FullName }
-```
-The `--check` argument prints the things that need to be fixed. If you remove
-it, `rustfmt` will update your files locally instead.
-
-You can run loom tests with
-```
-cd tokio # tokio crate in workspace
-LOOM_MAX_PREEMPTIONS=1 LOOM_MAX_BRANCHES=10000 RUSTFLAGS="--cfg loom -C debug_assertions" \
-    cargo test --lib --release --features full -- --test-threads=1 --nocapture
-```
-Additionally, you can also add `--cfg tokio_unstable` to the `RUSTFLAGS` environment variable to
-run loom tests that test unstable features.
-
-You can run miri tests with
-```
-MIRIFLAGS="-Zmiri-disable-isolation -Zmiri-strict-provenance -Zmiri-retag-fields" \
-    cargo +nightly miri test --features full --lib --tests
-```
-
-### Performing spellcheck on tokio codebase
-
-You can perform spell-check on tokio codebase. For details of how to use the spellcheck tool, feel free to visit
-https://github.com/drahnr/cargo-spellcheck
-```
-# First install the spell-check plugin
-cargo install --locked cargo-spellcheck
-
-# Then run the cargo spell check command
-cargo spellcheck check
-```
-
-if the command rejects a word, you should backtick the rejected word if it's code related. If not, the
-rejected word should be put into `spellcheck.dic` file.
-
-Note that when you add a word into the file, you should also update the first line which tells the spellcheck tool
-the total number of words included in the file
-
-### Tests
-
-If the change being proposed alters code (as opposed to only documentation for
-example), it is either adding new functionality to Tokio or it is fixing
-existing, broken functionality. In both of these cases, the pull request should
-include one or more tests to ensure that Tokio does not regress in the future.
-There are two ways to write tests: [integration tests][integration-tests]
-and [documentation tests][documentation-tests].
-(Tokio avoids [unit tests][unit-tests] as much as possible).
-
-Tokio uses [conditional compilation attributes][conditional-compilation]
-throughout the codebase, to modify rustc's behavior. Code marked with such
-attributes can be enabled using RUSTFLAGS and RUSTDOCFLAGS environment
-variables. One of the most prevalent flags passed in these variables is
-the `--cfg` option. To run tests in a particular file, check first what
-options #![cfg] declaration defines for that file.
-
-For instance, to run a test marked with the 'tokio_unstable' cfg option,
-you must pass this flag to the compiler when running the test.
-```
-$ RUSTFLAGS="--cfg tokio_unstable" cargo test -p tokio --all-features --test rt_metrics
-```
-
-#### Integration tests
-
-Integration tests go in the same crate as the code they are testing. Each sub
-crate should have a `dev-dependency` on `tokio` itself. This makes all Tokio
-utilities available to use in tests, no matter the crate being tested.
-
-The best strategy for writing a new integration test is to look at existing
-integration tests in the crate and follow the style.
-
-#### Fuzz tests
-
-Some of our crates include a set of fuzz tests, this will be marked by a
-directory `fuzz`. It is a good idea to run fuzz tests after each change.
-To get started with fuzz testing you'll need to install
-[cargo-fuzz](https://github.com/rust-fuzz/cargo-fuzz).
-
-`cargo install --locked cargo-fuzz`
-
-To list the available fuzzing harnesses you can run;
-
-```bash
-$ cd tokio
-$ cargo fuzz list
-fuzz_linked_list
-```
-
-Running a fuzz test is as simple as;
-
-`cargo fuzz run fuzz_linked_list`
-
-**NOTE**: Keep in mind that by default when running a fuzz test the fuzz
-harness will run forever and will only exit if you `ctrl-c` or it finds
-a bug.
-
-#### Documentation tests
-
-Ideally, every API has at least one [documentation test] that demonstrates how to
-use the API. Documentation tests are run with `cargo test --doc`. This ensures
-that the example is correct and provides additional test coverage.
-
-The trick to documentation tests is striking a balance between being succinct
-for a reader to understand and actually testing the API.
-
-Same as with integration tests, when writing a documentation test, the full
-`tokio` crate is available. This is especially useful for getting access to the
-runtime to run the example.
-
-The documentation tests will be visible from both the crate specific
-documentation **and** the `tokio` facade documentation via the re-export. The
-example should be written from the point of view of a user that is using the
-`tokio` crate. As such, the example should use the API via the facade and not by
-directly referencing the crate.
-
-The type level example for `tokio_timer::Timeout` provides a good example of a
-documentation test:
-
-```
-/// // import the `timeout` function, usually this is done
-/// // with `use tokio::prelude::*`
-/// use tokio::prelude::FutureExt;
-/// use futures::Stream;
-/// use futures::sync::mpsc;
-/// use std::time::Duration;
-///
-/// # fn main() {
-/// let (tx, rx) = mpsc::unbounded();
-/// # tx.unbounded_send(()).unwrap();
-/// # drop(tx);
-///
-/// let process = rx.for_each(|item| {
-///     // do something with `item`
-/// # drop(item);
-/// # Ok(())
-/// });
-///
-/// # tokio::runtime::current_thread::block_on_all(
-/// // Wrap the future with a `Timeout` set to expire in 10 milliseconds.
-/// process.timeout(Duration::from_millis(10))
-/// # ).unwrap();
-/// # }
-```
-
-Given that this is a *type* level documentation test and the primary way users
-of `tokio` will create an instance of `Timeout` is by using
-`FutureExt::timeout`, this is how the documentation test is structured.
-
-Lines that start with `/// #` are removed when the documentation is generated.
-They are only there to get the test to run. The `block_on_all` function is the
-easiest way to execute a future from a test.
-
-If this were a documentation test for the `Timeout::new` function, then the
-example would explicitly use `Timeout::new`. For example:
-
-```
-/// use tokio::timer::Timeout;
-/// use futures::Future;
-/// use futures::sync::oneshot;
-/// use std::time::Duration;
-///
-/// # fn main() {
-/// let (tx, rx) = oneshot::channel();
-/// # tx.send(()).unwrap();
-///
-/// # tokio::runtime::current_thread::block_on_all(
-/// // Wrap the future with a `Timeout` set to expire in 10 milliseconds.
-/// Timeout::new(rx, Duration::from_millis(10))
-/// # ).unwrap();
-/// # }
-```
-
-### Benchmarks
-
-You can run benchmarks locally for the changes you've made to the tokio codebase.
-Tokio currently uses [Criterion](https://github.com/bheisler/criterion.rs) as its benchmarking tool. To run a benchmark
-against the changes you have made, for example, you can run;
-
-```bash
-cd benches
-
-# Run all benchmarks.
-cargo bench
-
-# Run all tests in the `benches/fs.rs` file
-cargo bench --bench fs
-
-# Run the `async_read_buf` benchmark in `benches/fs.rs` specifically.
-cargo bench async_read_buf
-
-# After running benches, you can check the statistics under `tokio/target/criterion/`
-```
-
-You can also refer to Criterion docs for additional options and details.
-
-### Commits
-
-It is a recommended best practice to keep your changes as logically grouped as
-possible within individual commits. There is no limit to the number of commits
-any single Pull Request may have, and many contributors find it easier to review
-changes that are split across multiple commits.
-
-That said, if you have a number of commits that are "checkpoints" and don't
-represent a single logical change, please squash those together.
-
-Note that multiple commits often get squashed when they are landed (see the
-notes about [commit squashing](#commit-squashing)).
-
-#### Commit message guidelines
-
-A good commit message should describe what changed and why.
-
-1. The first line should:
-
-  * contain a short description of the change (preferably 50 characters or less,
-    and no more than 72 characters)
-  * be entirely in lowercase with the exception of proper nouns, acronyms, and
-    the words that refer to code, like function/variable names
-  * start with an imperative verb
-  * not have a period at the end
-  * be prefixed with the name of the module being changed; usually this is the
-    same as the M-* label on the PR
-
-  Examples:
-
-  * time: introduce `Timeout` and deprecate `Deadline`
-  * codec: export `Encoder`, `Decoder`, `Framed*`
-  * ci: fix the FreeBSD ci configuration
-
-2. Keep the second line blank.
-3. Wrap all other lines at 72 columns (except for long URLs).
-4. If your patch fixes an open issue, you can add a reference to it at the end
-   of the log. Use the `Fixes: #` prefix and the issue number. For other
-   references use `Refs: #`. `Refs` may include multiple issues, separated by a
-   comma.
-
-   Examples:
-
-   - `Fixes: #1337`
-   - `Refs: #1234`
-
-Sample complete commit message:
-
-```txt
-module: explain the commit in one line
-
-Body of commit message is a few lines of text, explaining things
-in more detail, possibly giving some background about the issue
-being fixed, etc.
-
-The body of the commit message can be several paragraphs, and
-please do proper word-wrap and keep columns shorter than about
-72 characters or so. That way, `git log` will show things
-nicely even when it is indented.
-
-Fixes: #1337
-Refs: #453, #154
-```
-
-### Opening the Pull Request
-
-From within GitHub, opening a new Pull Request will present you with a
-[template] that should be filled out. Please try to do your best at filling out
-the details, but feel free to skip parts if you're not sure what to put.
-
-[template]: .github/PULL_REQUEST_TEMPLATE.md
-
-### Discuss and update
-
-You will probably get feedback or requests for changes to your Pull Request.
-This is a big part of the submission process so don't be discouraged! Some
-contributors may sign off on the Pull Request right away, others may have
-more detailed comments or feedback. This is a necessary part of the process
-in order to evaluate whether the changes are correct and necessary.
-
-**Any community member can review a PR and you might get conflicting feedback**.
-Keep an eye out for comments from code owners to provide guidance on conflicting
-feedback.
-
-**Once the PR is open, do not rebase the commits**. See [Commit Squashing](#commit-squashing) for
-more details.
-
-### Commit Squashing
-
-In most cases, **do not squash commits that you add to your Pull Request during
-the review process**. When the commits in your Pull Request land, they may be
-squashed into one commit per logical change. Metadata will be added to the
-commit message (including links to the Pull Request, links to relevant issues,
-and the names of the reviewers). The commit history of your Pull Request,
-however, will stay intact on the Pull Request page.
-
-## Reviewing Pull Requests
-
-**Any Tokio community member is welcome to review any pull request**.
-
-All Tokio contributors who choose to review and provide feedback on Pull
-Requests have a responsibility to both the project and the individual making the
-contribution. Reviews and feedback must be helpful, insightful, and geared
-towards improving the contribution as opposed to simply blocking it. If there
-are reasons why you feel the PR should not land, explain what those are. Do not
-expect to be able to block a Pull Request from advancing simply because you say
-"No" without giving an explanation. Be open to having your mind changed. Be open
-to working with the contributor to make the Pull Request better.
-
-Reviews that are dismissive or disrespectful of the contributor or any other
-reviewers are strictly counter to the Code of Conduct.
-
-When reviewing a Pull Request, the primary goals are for the codebase to improve
-and for the person submitting the request to succeed. **Even if a Pull Request
-does not land, the submitters should come away from the experience feeling like
-their effort was not wasted or unappreciated**. Every Pull Request from a new
-contributor is an opportunity to grow the community.
-
-### Review a bit at a time.
-
-Do not overwhelm new contributors.
-
-It is tempting to micro-optimize and make everything about relative performance,
-perfect grammar, or exact style matches. Do not succumb to that temptation.
-
-Focus first on the most significant aspects of the change:
-
-1. Does this change make sense for Tokio?
-2. Does this change make Tokio better, even if only incrementally?
-3. Are there clear bugs or larger scale issues that need attending to?
-4. Is the commit message readable and correct? If it contains a breaking change
-   is it clear enough?
-
-Note that only **incremental** improvement is needed to land a PR. This means
-that the PR does not need to be perfect, only better than the status quo. Follow
-up PRs may be opened to continue iterating.
-
-When changes are necessary, *request* them, do not *demand* them, and **do not
-assume that the submitter already knows how to add a test or run a benchmark**.
-
-Specific performance optimization techniques, coding styles and conventions
-change over time. The first impression you give to a new contributor never does.
-
-Nits (requests for small changes that are not essential) are fine, but try to
-avoid stalling the Pull Request. Most nits can typically be fixed by the Tokio
-Collaborator landing the Pull Request but they can also be an opportunity for
-the contributor to learn a bit more about the project.
-
-It is always good to clearly indicate nits when you comment: e.g.
-`Nit: change foo() to bar(). But this is not blocking.`
-
-If your comments were addressed but were not folded automatically after new
-commits or if they proved to be mistaken, please, [hide them][hiding-a-comment]
-with the appropriate reason to keep the conversation flow concise and relevant.
-
-### Be aware of the person behind the code
-
-Be aware that *how* you communicate requests and reviews in your feedback can
-have a significant impact on the success of the Pull Request. Yes, we may land
-a particular change that makes Tokio better, but the individual might just not
-want to have anything to do with Tokio ever again. The goal is not just having
-good code.
-
-### Abandoned or Stalled Pull Requests
-
-If a Pull Request appears to be abandoned or stalled, it is polite to first
-check with the contributor to see if they intend to continue the work before
-checking if they would mind if you took it over (especially if it just has nits
-left). When doing so, it is courteous to give the original contributor credit
-for the work they started (either by preserving their name and email address in
-the commit log, or by using an `Author: ` meta-data tag in the commit.
-
-_Adapted from the [Node.js contributing guide][node]_.
-
-[node]: https://github.com/nodejs/node/blob/master/CONTRIBUTING.md
-[hiding-a-comment]: https://help.github.com/articles/managing-disruptive-comments/#hiding-a-comment
-[documentation test]: https://doc.rust-lang.org/rustdoc/documentation-tests.html
-
-## Keeping track of issues and PRs
-
-The Tokio GitHub repository has a lot of issues and PRs to keep track of. This
-section explains the meaning of various labels, as well as our [GitHub
-project][project]. The section is primarily targeted at maintainers.  Most
-contributors aren't able to set these labels.
-
-### Area
-
-The area label describes the crates relevant to this issue or PR.
-
- - **A-tokio** This issue concerns the main Tokio crate.
- - **A-tokio-util** This issue concerns the `tokio-util` crate.
- - **A-tokio-tls** This issue concerns the `tokio-tls` crate. Only used for
-   older issues, as the crate has been moved to another repository.
- - **A-tokio-test** The issue concerns the `tokio-test` crate.
- - **A-tokio-macros** This issue concerns the `tokio-macros` crate. Should only
-   be used for the procedural macros, and not `join!` or `select!`.
- - **A-ci** This issue concerns our GitHub Actions setup.
-
-### Category
-
- - **C-bug** This is a bug-report. Bug-fix PRs use `C-enhancement` instead.
- - **C-enhancement** This is a PR that adds a new features.
- - **C-maintenance** This is an issue or PR about stuff such as documentation,
-   GitHub Actions or code quality.
- - **C-feature-request** This is a feature request. Implementations of feature
-   requests use `C-enhancement` instead.
- - **C-feature-accepted** If you submit a PR for this feature request, we wont
-   close it with the reason "we don't want this". Issues with this label should
-   also have the `C-feature-request` label.
- - **C-musing** Stuff like tracking issues or roadmaps. "musings about a better
-   world"
- - **C-proposal** A proposal of some kind, and a request for comments.
- - **C-question** A user question. Large overlap with GitHub discussions.
- - **C-request** A non-feature request, e.g. "please add deprecation notices to
-   `-alpha.*` versions of crates"
-
-### Calls for participation
-
- - **E-help-wanted** Stuff where we want help. Often seen together with `C-bug`
-   or `C-feature-accepted`.
- - **E-easy** This is easy, ranging from quick documentation fixes to stuff you
-   can do after reading the tutorial on our website.
- - **E-medium** This is not `E-easy` or `E-hard`.
- - **E-hard** This either involves very tricky code, is something we don't know
-   how to solve, or is difficult for some other reason.
- - **E-needs-mvce** This bug is missing a minimal complete and verifiable
-   example.
-
-The "E-" prefix is the same as used in the Rust compiler repository. Some
-issues are missing a difficulty rating, but feel free to ask on our Discord
-server if you want to know how difficult an issue likely is.
-
-### Module
-
-The module label provides a more fine grained categorization than **Area**.
-
- - **M-blocking** Things relevant to `spawn_blocking`, `block_in_place`.
- - **M-codec** The `tokio_util::codec` module.
- - **M-compat** The `tokio_util::compat` module.
- - **M-coop** Things relevant to coop.
- - **M-fs** The `tokio::fs` module.
- - **M-io** The `tokio::io` module.
- - **M-macros** Issues about any kind of macro.
- - **M-net** The `tokio::net` module.
- - **M-process** The `tokio::process` module.
- - **M-runtime** The `tokio::runtime` module.
- - **M-signal** The `tokio::signal` module.
- - **M-sync** The `tokio::sync` module.
- - **M-task** The `tokio::task` module.
- - **M-time** The `tokio::time` module.
- - **M-tracing** Tracing support in Tokio.
-
-### Topic
-
-Some extra information.
-
- - **T-docs** This is about documentation.
- - **T-performance** This is about performance.
- - **T-v0.1.x** This is about old Tokio.
-
-Any label not listed here is not in active use.
-
-[project]: https://github.com/orgs/tokio-rs/projects/1
+[Discord server]: https://discord.gg/tokio
 
 ## LTS guarantees
 
-Tokio ≥1.0.0 comes with LTS guarantees:
-
- * A minimum of 5 years of maintenance.
- * A minimum of 3 years before a hypothetical 2.0 release.
+In Tokio ≥1.0.0, each LTS release comes with the guarantee of at least one year of
+backported fixes.
 
 The goal of these guarantees is to provide stability to the ecosystem.
 
 ## Minimum Supported Rust Version (MSRV)
 
- * All Tokio ≥1.0.0 releases will support at least a 6-month old Rust
-   compiler release.
- * The MSRV will only be increased on 1.x releases.
+* All Tokio ≥1.0.0 releases will support at least a 6-month old Rust
+  compiler release.
+* The MSRV will only be increased on 1.x releases.
 
 ## Versioning Policy
 
 With Tokio ≥1.0.0:
 
- * Patch (1.\_.x) releases _should only_ contain bug fixes or documentation
-   changes. Besides this, these releases should not substantially change
-   runtime behavior.
- * Minor (1.x) releases may contain new functionality, MSRV increases (see
-   above), minor dependency updates, deprecations, and larger internal
-   implementation changes.
+* Patch (1.\_.x) releases _should only_ contain bug fixes or documentation
+  changes. Besides this, these releases should not substantially change
+  runtime behavior.
+* Minor (1.x) releases may contain new functionality, MSRV increases (see
+  above), minor dependency updates, deprecations, and larger internal
+  implementation changes.
 
 This is as defined by [Semantic Versioning 2.0](https://semver.org/).
-
-## Releasing
-
-Since the Tokio project consists of a number of crates, many of which depend on
-each other, releasing new versions to crates.io can involve some complexities.
-When releasing a new version of a crate, follow these steps:
-
-1. **Ensure that the release crate has no path dependencies.** When the HEAD
-   version of a Tokio crate requires unreleased changes in another Tokio crate,
-   the crates.io dependency on the second crate will be replaced with a path
-   dependency. Crates with path dependencies cannot be published, so before
-   publishing the dependent crate, any path dependencies must also be published.
-   This should be done through a form of depth-first tree traversal:
-
-   1. Starting with the first path dependency in the crate to be released,
-      inspect the `Cargo.toml` for the dependency. If the dependency has any
-      path dependencies of its own, repeat this step with the first such
-      dependency.
-   2. Begin the release process for the path dependency.
-   3. Once the path dependency has been published to crates.io, update the
-      dependent crate to depend on the crates.io version.
-   4. When all path dependencies have been published, the dependent crate may
-      be published.
-
-   To verify that a crate is ready to publish, run:
-
-   ```bash
-   bin/publish --dry-run <CRATE NAME> <CRATE VERSION>
-   ```
-
-2. **Update Cargo metadata.** After releasing any path dependencies, update the
-   `version` field in `Cargo.toml` to the new version, and the `documentation`
-   field to the docs.rs URL of the new version.
-3. **Update other documentation links.** Update the "Documentation" link in the
-   crate's `README.md` to point to the docs.rs URL of the new version.
-4. **Update the changelog for the crate.** Each crate in the Tokio repository
-   has its own `CHANGELOG.md` in that crate's subdirectory. Any changes to that
-   crate since the last release should be added to the changelog. Change
-   descriptions may be taken from the Git history, but should be edited to
-   ensure a consistent format, based on [Keep A Changelog][keep-a-changelog].
-   Other entries in that crate's changelog may also be used for reference.
-5. **Perform a final audit for breaking changes.** Compare the HEAD version of
-   crate with the Git tag for the most recent release version. If there are any
-   breaking API changes, determine if those changes can be made without breaking
-   existing APIs. If so, resolve those issues. Otherwise, if it is necessary to
-   make a breaking release, update the version numbers to reflect this.
-6. **Open a pull request with your changes.** Once that pull request has been
-   approved by a maintainer and the pull request has been merged, continue to
-   the next step.
-7. **Release the crate.** Run the following command:
-
-   ```bash
-   bin/publish <NAME OF CRATE> <VERSION>
-   ```
-
-   Your editor and prompt you to edit a message for the tag. Copy the changelog
-   entry for that release version into your editor and close the window.
-
-[keep-a-changelog]: https://github.com/olivierlacan/keep-a-changelog/blob/master/CHANGELOG.md
-[unit-tests]: https://doc.rust-lang.org/rust-by-example/testing/unit_testing.html
-[integration-tests]: https://doc.rust-lang.org/rust-by-example/testing/integration_testing.html
-[documentation-tests]: https://doc.rust-lang.org/rust-by-example/testing/doc_testing.html
-[conditional-compilation]: https://doc.rust-lang.org/reference/conditional-compilation.html

Cargo.toml

@@ -15,6 +15,13 @@ members = [
   "tests-integration",
 ]
 
+[patch.crates-io]
+tokio = { path = "tokio" }
+tokio-macros = { path = "tokio-macros" }
+tokio-stream = { path = "tokio-stream" }
+tokio-test = { path = "tokio-test" }
+tokio-util = { path = "tokio-util" }
+
 [workspace.metadata.spellcheck]
 config = "spellcheck.toml"
 
@@ -27,6 +34,6 @@ unexpected_cfgs = { level = "warn", check-cfg = [
   'cfg(tokio_internal_mt_counters)',
   'cfg(tokio_no_parking_lot)',
   'cfg(tokio_no_tuning_tests)',
-  'cfg(tokio_taskdump)',
   'cfg(tokio_unstable)',
+  'cfg(target_os, values("cygwin"))',
 ] }

README.md

@@ -1,3 +1,7 @@
+*[TokioConf 2026 program and tickets are now available!](https://tokioconf.com)*
+
+---
+
 # Tokio
 
 A runtime for writing reliable, asynchronous, and slim applications with
@@ -39,7 +43,7 @@ level, it provides a few major components:
 
 * A multithreaded, work-stealing based task [scheduler].
 * A reactor backed by the operating system's event queue (epoll, kqueue,
-  IOCP, etc...).
+  IOCP, etc.).
 * Asynchronous [TCP and UDP][net] sockets.
 
 These components provide the runtime components necessary for building
@@ -52,11 +56,11 @@ an asynchronous application.
 
 A basic TCP echo server with Tokio.
 
-Make sure you activated the full features of the tokio crate on Cargo.toml:
+Make sure you enable the full features of the tokio crate on Cargo.toml:
 
 ```toml
 [dependencies]
-tokio = { version = "1.44.2", features = ["full"] }
+tokio = { version = "1.52.3", features = ["full"] }
 ```
 Then, on your main.rs:
 
@@ -103,7 +107,7 @@ More examples can be found [here][examples]. For a larger "real world" example,
 [examples]: https://github.com/tokio-rs/tokio/tree/master/examples
 [mini-redis]: https://github.com/tokio-rs/mini-redis/
 
-To see a list of the available features flags that can be enabled, check our
+To see a list of the available feature flags that can be enabled, check our
 [docs][feature-flag-docs].
 
 ## Getting Help
@@ -125,7 +129,7 @@ question. You can also ask your question on [the discussions page][discussions].
 you! We have a [contributing guide][guide] to help you get involved in the Tokio
 project.
 
-[guide]: https://github.com/tokio-rs/tokio/blob/master/CONTRIBUTING.md
+[guide]: https://github.com/tokio-rs/tokio/blob/master/docs/contributing/README.md
 
 ## Related Projects
 
@@ -186,12 +190,13 @@ When updating this, also update:
 
 Tokio will keep a rolling MSRV (minimum supported rust version) policy of **at
 least** 6 months. When increasing the MSRV, the new Rust version must have been
-released at least six months ago. The current MSRV is 1.70.
+released at least six months ago. The current MSRV is 1.71.
 
 Note that the MSRV is not increased automatically, and only as part of a minor
 release. The MSRV history for past minor releases can be found below:
 
- * 1.39 to now  - Rust 1.70
+ * 1.48 to now  - Rust 1.71
+ * 1.39 to 1.47 - Rust 1.70
  * 1.30 to 1.38 - Rust 1.63
  * 1.27 to 1.29 - Rust 1.56
  * 1.17 to 1.26 - Rust 1.49
@@ -216,18 +221,18 @@ warrants a patch release with a fix for the bug, it will be backported and
 released as a new patch release for each LTS minor version. Our current LTS
 releases are:
 
- * `1.38.x` - LTS release until July 2025. (MSRV 1.63)
- * `1.43.x` - LTS release until March 2026. (MSRV 1.70)
+ * `1.47.x` - LTS release until September 2026. (MSRV 1.70)
+ * `1.51.x` - LTS release until March 2027. (MSRV 1.71)
 
 Each LTS release will continue to receive backported fixes for at least a year.
 If you wish to use a fixed minor release in your project, we recommend that you
 use an LTS release.
 
 To use a fixed minor version, you can specify the version with a tilde. For
-example, to specify that you wish to use the newest `1.32.x` patch release, you
+example, to specify that you wish to use the newest `1.47.x` patch release, you
 can use the following dependency specification:
 ```text
-tokio = { version = "~1.38", features = [...] }
+tokio = { version = "~1.47", features = [...] }
 ```
 
 ### Previous LTS releases
@@ -239,6 +244,8 @@ tokio = { version = "~1.38", features = [...] }
  * `1.25.x` - LTS release until March 2024.
  * `1.32.x` - LTS release until September 2024.
  * `1.36.x` - LTS release until March 2025.
+ * `1.38.x` - LTS release until July 2025.
+ * `1.43.x` - LTS release until March 2026.
 
 ## License
 
@@ -249,5 +256,5 @@ This project is licensed under the [MIT license].
 ### Contribution
 
 Unless you explicitly state otherwise, any contribution intentionally submitted
-for inclusion in Tokio by you, shall be licensed as MIT, without any additional
+for inclusion in Tokio by you shall be licensed as MIT, without any additional
 terms or conditions.

benches/Cargo.toml

@@ -11,8 +11,8 @@ test-util = ["tokio/test-util"]
 [dependencies]
 tokio = { version = "1.5.0", path = "../tokio", features = ["full"] }
 criterion = "0.5.1"
-rand = "0.8"
-rand_chacha = "0.3"
+rand = "0.9"
+rand_chacha = "0.9"
 
 [dev-dependencies]
 tokio-util = { version = "0.7.0", path = "../tokio-util", features = ["full"] }
@@ -96,5 +96,15 @@ name = "time_timeout"
 path = "time_timeout.rs"
 harness = false
 
+[[bench]]
+name = "spawn_blocking"
+path = "spawn_blocking.rs"
+harness = false
+
+[[bench]]
+name = "remote_spawn"
+path = "remote_spawn.rs"
+harness = false
+
 [lints]
 workspace = true

benches/copy.rs

@@ -77,7 +77,7 @@ impl SlowHddWriter {
     ) -> std::task::Poll<Result<usize, std::io::Error>> {
         let service_res = self.as_mut().service_write(cx);
 
-        if service_res.is_pending() && self.blocking_rng.gen_bool(PROBABILITY_FLUSH_WAIT) {
+        if service_res.is_pending() && self.blocking_rng.random_bool(PROBABILITY_FLUSH_WAIT) {
             return Poll::Pending;
         }
         let available = self.buffer_size - self.buffer_used;
@@ -145,7 +145,7 @@ impl ChunkReader {
     fn new(chunk_size: usize, service_interval: Duration) -> Self {
         let mut service_intervals = interval(service_interval);
         service_intervals.set_missed_tick_behavior(MissedTickBehavior::Burst);
-        let data: Vec<u8> = std::iter::repeat(0).take(chunk_size).collect();
+        let data: Vec<u8> = std::iter::repeat_n(0, chunk_size).collect();
         Self {
             data,
             service_intervals,

benches/remote_spawn.rs

@@ -0,0 +1,103 @@
+//! Benchmark remote task spawning (push_remote_task) at different concurrency
+//! levels on the multi-threaded scheduler.
+//!
+//! This measures contention on the scheduler's inject queue mutex when multiple
+//! external (non-worker) threads spawn tasks into the tokio runtime simultaneously.
+//! Every rt.spawn() from an external thread unconditionally goes through
+//! push_remote_task, making this a direct measurement of inject queue contention.
+//!
+//! For each parallelism level N (1, 2, 4, 8, 16, 32, 64, capped at available parallelism):
+//! - Spawns N std::threads (external to the runtime)
+//! - Each thread spawns TOTAL_TASKS / N tasks into the runtime via rt.spawn()
+//! - All threads are synchronized with a barrier to maximize contention
+//! - Tasks are trivial no-ops to isolate the push overhead
+
+use criterion::{criterion_group, criterion_main, BenchmarkId, Criterion};
+use std::sync::Barrier;
+use tokio::runtime::{self, Runtime};
+
+/// Total number of tasks spawned across all threads per iteration.
+/// Must be divisible by the largest parallelism level (64).
+const TOTAL_TASKS: usize = 12_800;
+const _: () = assert!(
+    TOTAL_TASKS.is_multiple_of(64),
+    "TOTAL_TASKS must be divisible by 64"
+);
+
+fn remote_spawn_contention(c: &mut Criterion) {
+    let parallelism_levels = parallelism_levels();
+    let mut group = c.benchmark_group("remote_spawn");
+
+    for num_threads in &parallelism_levels {
+        let num_threads = *num_threads;
+        group.bench_with_input(
+            BenchmarkId::new("threads", num_threads),
+            &num_threads,
+            |b, &num_threads| {
+                let rt = rt();
+                let tasks_per_thread = TOTAL_TASKS / num_threads;
+                let barrier = Barrier::new(num_threads);
+
+                b.iter_custom(|iters| {
+                    let mut total_duration = std::time::Duration::ZERO;
+                    for _ in 0..iters {
+                        let start = std::time::Instant::now();
+
+                        let all_handles = std::thread::scope(|s| {
+                            let handles: Vec<_> = (0..num_threads)
+                                .map(|_| {
+                                    let barrier = &barrier;
+                                    let rt = &rt;
+                                    s.spawn(move || {
+                                        let mut join_handles = Vec::with_capacity(tasks_per_thread);
+                                        barrier.wait();
+
+                                        for _ in 0..tasks_per_thread {
+                                            join_handles.push(rt.spawn(async {}));
+                                        }
+                                        join_handles
+                                    })
+                                })
+                                .collect();
+
+                            handles
+                                .into_iter()
+                                .flat_map(|h| h.join().unwrap())
+                                .collect::<Vec<_>>()
+                        });
+
+                        total_duration += start.elapsed();
+
+                        rt.block_on(async {
+                            for h in all_handles {
+                                h.await.unwrap();
+                            }
+                        });
+                    }
+                    total_duration
+                });
+            },
+        );
+    }
+
+    group.finish();
+}
+
+fn parallelism_levels() -> Vec<usize> {
+    let max_parallelism = std::thread::available_parallelism()
+        .map(|p| p.get())
+        .unwrap_or(1);
+
+    [1, 2, 4, 8, 16, 32, 64]
+        .into_iter()
+        .filter(|&n| n <= max_parallelism)
+        .collect()
+}
+
+fn rt() -> Runtime {
+    runtime::Builder::new_multi_thread().build().unwrap()
+}
+
+criterion_group!(remote_spawn_benches, remote_spawn_contention);
+
+criterion_main!(remote_spawn_benches);

benches/spawn.rs

@@ -10,10 +10,21 @@ async fn work() -> usize {
     black_box(val)
 }
 
-fn basic_scheduler_spawn(c: &mut Criterion) {
-    let runtime = tokio::runtime::Builder::new_current_thread()
+fn single_rt() -> tokio::runtime::Runtime {
+    tokio::runtime::Builder::new_current_thread()
         .build()
-        .unwrap();
+        .unwrap()
+}
+
+fn multi_rt() -> tokio::runtime::Runtime {
+    tokio::runtime::Builder::new_multi_thread()
+        .worker_threads(1)
+        .build()
+        .unwrap()
+}
+
+fn basic_scheduler_spawn(c: &mut Criterion) {
+    let runtime = single_rt();
 
     c.bench_function("basic_scheduler_spawn", |b| {
         b.iter(|| {
@@ -26,9 +37,7 @@ fn basic_scheduler_spawn(c: &mut Criterion) {
 }
 
 fn basic_scheduler_spawn10(c: &mut Criterion) {
-    let runtime = tokio::runtime::Builder::new_current_thread()
-        .build()
-        .unwrap();
+    let runtime = single_rt();
 
     c.bench_function("basic_scheduler_spawn10", |b| {
         b.iter(|| {
@@ -46,10 +55,8 @@ fn basic_scheduler_spawn10(c: &mut Criterion) {
 }
 
 fn threaded_scheduler_spawn(c: &mut Criterion) {
-    let runtime = tokio::runtime::Builder::new_multi_thread()
-        .worker_threads(1)
-        .build()
-        .unwrap();
+    let runtime = multi_rt();
+
     c.bench_function("threaded_scheduler_spawn", |b| {
         b.iter(|| {
             runtime.block_on(async {
@@ -61,10 +68,8 @@ fn threaded_scheduler_spawn(c: &mut Criterion) {
 }
 
 fn threaded_scheduler_spawn10(c: &mut Criterion) {
-    let runtime = tokio::runtime::Builder::new_multi_thread()
-        .worker_threads(1)
-        .build()
-        .unwrap();
+    let runtime = multi_rt();
+
     c.bench_function("threaded_scheduler_spawn10", |b| {
         b.iter(|| {
             runtime.block_on(async {

benches/spawn_blocking.rs

@@ -0,0 +1,73 @@
+//! Benchmark spawn_blocking at different concurrency levels on the multi-threaded scheduler.
+//!
+//! For each parallelism level N (1, 2, 4, 8, 16, 32, 64, capped at available parallelism):
+//! - Spawns N regular async tasks
+//! - Each task spawns M batches of B spawn_blocking tasks (no-ops)
+//! - Each batch is awaited to completion before starting the next
+
+use criterion::{black_box, criterion_group, criterion_main, BenchmarkId, Criterion};
+use tokio::runtime::{self, Runtime};
+use tokio::task::JoinSet;
+
+/// Number of batches per task
+const NUM_BATCHES: usize = 100;
+/// Number of spawn_blocking calls per batch
+const BATCH_SIZE: usize = 16;
+
+fn spawn_blocking_concurrency(c: &mut Criterion) {
+    let max_parallelism = std::thread::available_parallelism()
+        .map(|p| p.get())
+        .unwrap_or(1);
+
+    let parallelism_levels: Vec<usize> = [1, 2, 4, 8, 16, 32, 64]
+        .into_iter()
+        .filter(|&n| n <= max_parallelism)
+        .collect();
+
+    let mut group = c.benchmark_group("spawn_blocking");
+
+    for num_tasks in parallelism_levels {
+        group.bench_with_input(
+            BenchmarkId::new("concurrency", num_tasks),
+            &num_tasks,
+            |b, &num_tasks| {
+                let rt = rt();
+
+                b.iter(|| {
+                    rt.block_on(async {
+                        let mut tasks = JoinSet::new();
+
+                        for _ in 0..num_tasks {
+                            tasks.spawn(async {
+                                for _ in 0..NUM_BATCHES {
+                                    let mut batch = JoinSet::new();
+
+                                    for _ in 0..BATCH_SIZE {
+                                        batch.spawn_blocking(|| black_box(0));
+                                    }
+
+                                    batch.join_all().await;
+                                }
+                            });
+                        }
+
+                        tasks.join_all().await;
+                    });
+                });
+            },
+        );
+    }
+
+    group.finish();
+}
+
+fn rt() -> Runtime {
+    runtime::Builder::new_multi_thread()
+        .enable_all()
+        .build()
+        .unwrap()
+}
+
+criterion_group!(spawn_blocking_benches, spawn_blocking_concurrency);
+
+criterion_main!(spawn_blocking_benches);

benches/sync_broadcast.rs

@@ -17,7 +17,7 @@ fn do_work(rng: &mut impl RngCore) -> u32 {
     use std::fmt::Write;
     let mut message = String::new();
     for i in 1..=10 {
-        let _ = write!(&mut message, " {i}={}", rng.gen::<f64>());
+        let _ = write!(&mut message, " {i}={}", rng.random::<f64>());
     }
     message
         .as_bytes()

benches/sync_watch.rs

@@ -17,7 +17,7 @@ fn do_work(rng: &mut impl RngCore) -> u32 {
     use std::fmt::Write;
     let mut message = String::new();
     for i in 1..=10 {
-        let _ = write!(&mut message, " {i}={}", rng.gen::<f64>());
+        let _ = write!(&mut message, " {i}={}", rng.random::<f64>());
     }
     message
         .as_bytes()

deny.toml

@@ -9,7 +9,7 @@ allow = [
     "Apache-2.0",
 ]
 exceptions = [
-    { allow = ["Unicode-3.0", "Unicode-DFS-2016"], crate = "unicode-ident" },
+    { allow = ["Unicode-3.0"], crate = "unicode-ident" },
 ]
 
 [bans]

docs/contributing/README.md

@@ -0,0 +1,47 @@
+# Contributing
+
+This guide will help you get started. **Do not let this guide intimidate you**.
+It should be considered a map to help you navigate the process.
+
+## Quick start
+
+If you are unsure where to begin, use the following guides:
+
+- Want to report or triage a bug? Start with [Contributing in Issues](contributing-in-issues.md).
+- Looking for something to work on? Check the open [`issues`](https://github.com/tokio-rs/tokio/issues)
+(some might be in progress or still under discussion, so leave a comment before starting the work).
+- Planning to submit a PR? Read [Pull Requests](pull-requests.md) for the full workflow and required checks.
+- Want to understand what the labels on issues mean? See [Keeping track of issues and PRs](keeping-track-of-issues-and-prs.md).
+- Interested in code review? See [Reviewing Pull Requests](reviewing-pull-requests.md).
+
+## Table of Contents
+
+- [Contributing in Issues](contributing-in-issues.md)
+    - [Asking for General Help](contributing-in-issues.md#asking-for-general-help)
+    - [Submitting a Bug Report](contributing-in-issues.md#submitting-a-bug-report)
+    - [Triaging a Bug Report](contributing-in-issues.md#triaging-a-bug-report)
+    - [Resolving a Bug Report](contributing-in-issues.md#resolving-a-bug-report)
+- [Pull Requests](pull-requests.md)
+    - [Cargo Commands](pull-requests.md#cargo-commands)
+    - [Performing spellcheck on Tokio codebase](pull-requests.md#performing-spellcheck-on-tokio-codebase)
+    - [Tests](pull-requests.md#tests)
+        - [Integration tests](pull-requests.md#integration-tests)
+        - [Fuzz tests](pull-requests.md#fuzz-tests)
+        - [Documentation tests](pull-requests.md#documentation-tests)
+    - [Benchmarks](pull-requests.md#benchmarks)
+    - [Commits](pull-requests.md#commits)
+        - [Commit message guidelines](pull-requests.md#commit-message-guidelines)
+    - [Opening the Pull Request](pull-requests.md#opening-the-pull-request)
+    - [Discuss and update](pull-requests.md#discuss-and-update)
+    - [Commit Squashing](pull-requests.md#commit-squashing)
+- [Reviewing Pull Requests](reviewing-pull-requests.md)
+    - [Review a bit at a time](reviewing-pull-requests.md#review-a-bit-at-a-time)
+    - [Be aware of the person behind the code](reviewing-pull-requests.md#be-aware-of-the-person-behind-the-code)
+    - [Abandoned or Stalled Pull Requests](reviewing-pull-requests.md#abandoned-or-stalled-pull-requests)
+- [How to specify crates dependencies versions](how-to-specify-crates-dependencies-versions.md)
+- [Keeping track of issues and PRs](keeping-track-of-issues-and-prs.md)
+    - [Area](keeping-track-of-issues-and-prs.md#area)
+    - [Category](keeping-track-of-issues-and-prs.md#category)
+    - [Calls for participation](keeping-track-of-issues-and-prs.md#calls-for-participation)
+    - [Module](keeping-track-of-issues-and-prs.md#module)
+    - [Topic](keeping-track-of-issues-and-prs.md#topic)

docs/contributing/contributing-in-issues.md

@@ -0,0 +1,79 @@
+## Contributing in Issues
+
+For any issue, there are fundamentally three ways an individual can contribute:
+
+1. By opening the issue for discussion: For instance, if you believe that you
+   have discovered a bug in Tokio, creating a new issue in [the tokio-rs/tokio
+   issue tracker][issue] is the way to report it.
+
+2. By helping to triage the issue: This can be done by providing
+   supporting details (a test case that demonstrates a bug), providing
+   suggestions on how to address the issue, or ensuring that the issue is tagged
+   correctly.
+
+3. By helping to resolve the issue: Typically this is done either in the form of
+   demonstrating that the issue reported is not a problem after all, or more
+   often, by opening a Pull Request that changes some bit of something in
+   Tokio in a concrete and reviewable manner.
+
+[issue]: https://github.com/tokio-rs/tokio/issues
+
+**Anybody can participate in any stage of contribution**. We urge you to
+participate in the discussion around bugs and participate in reviewing PRs.
+
+### Asking for General Help
+
+If you have reviewed existing documentation and still have questions or are
+having problems, you can [open a discussion] asking for help.
+
+In exchange for receiving help, we ask that you contribute back a documentation
+PR that helps others avoid the problems that you encountered.
+
+[open a discussion]: https://github.com/tokio-rs/tokio/discussions/new/choose
+
+### Submitting a Bug Report
+
+When opening a new issue in the Tokio issue tracker, you will be presented
+with a basic template that should be filled in. If you believe that you have
+uncovered a bug, please fill out this form, following the template to the best
+of your ability. Do not worry if you cannot answer every detail, just fill in
+what you can.
+
+The two most important pieces of information we need in order to properly
+evaluate the report is a description of the behavior you are seeing and a simple
+test case we can use to recreate the problem on our own. If we cannot recreate
+the issue, it becomes impossible for us to fix.
+
+In order to rule out the possibility of bugs introduced by userland code, test
+cases should be limited, as much as possible, to using only Tokio APIs.
+
+See [How to create a Minimal, Complete, and Verifiable example][mcve].
+
+[mcve]: https://stackoverflow.com/help/mcve
+
+### Triaging a Bug Report
+
+Once an issue has been opened, it is not uncommon for there to be discussion
+around it. Some contributors may have differing opinions about the issue,
+including whether the behavior being seen is a bug or a feature. This discussion
+is part of the process and should be kept focused, helpful, and professional.
+
+Short, clipped responses—that provide neither additional context nor supporting
+detail—are not helpful or professional. To many, such responses are simply
+annoying and unfriendly.
+
+Contributors are encouraged to help one another make forward progress as much as
+possible, empowering one another to solve issues collaboratively. If you choose
+to comment on an issue that you feel either is not a problem that needs to be
+fixed, or if you encounter information in an issue that you feel is incorrect,
+explain why you feel that way with additional supporting context, and be willing
+to be convinced that you may be wrong. By doing so, we can often reach the
+correct outcome much faster.
+
+### Resolving a Bug Report
+
+In the majority of cases, issues are resolved by opening a Pull Request. The
+process for opening and reviewing a Pull Request is similar to that of opening
+and triaging issues, but carries with it a necessary review and approval
+workflow that ensures that the proposed changes meet the minimal quality and
+functional guidelines of the Tokio project.

docs/contributing/how-to-specify-crates-dependencies-versions.md

@@ -0,0 +1,32 @@
+# How to specify crates dependencies versions
+
+Each crate (e.g., `tokio-util`, `tokio-stream`, etc.) should specify dependencies
+according to the following rules:
+
+1. The listed version should be the oldest version that the crate works with
+(e.g., if `tokio-util` works with `tokio` version `1.44` but not `1.43`, then
+`tokio-util` should specify version `1.44` for its `tokio` dependency).
+We don't require users to use the latest version unnecessarily.
+2. When a crate starts using a newer feature in a dependency, the version
+should be bumped to the version that introduced it.
+3. If a crate depends on an unreleased feature in a dependency, it may use
+`path =` dependency to specify this. Since path dependencies must be removed
+during the release of the crate, this ensures that it can't be released until
+the dependency has a new version.
+
+Consider the following example from `tokio-stream`:
+
+```toml
+[dependencies]
+futures-core = { version = "0.3.0" }
+pin-project-lite = "0.2.11"
+tokio = { version = "1.38.0", path = "../tokio", features = ["sync"] }
+```
+
+In this case, local development of `tokio-stream` uses the local version
+of `tokio` via the `path` dependency. This means that it's currently not
+possible to release `tokio-stream`, and `tokio` should be released first.
+Once a new version of `tokio` is released (in this example the `1.38.0`),
+the path dependency should be removed.
+As mentioned before, this version should only be bumped when adding a new
+feature in the crate that relies on a newer version.

docs/contributing/keeping-track-of-issues-and-prs.md

@@ -0,0 +1,91 @@
+## Keeping track of issues and PRs
+
+The Tokio GitHub repository has a lot of issues and PRs to keep track of. This
+section explains the meaning of various labels, as well as our [GitHub
+project][project]. The section is primarily targeted at maintainers.  Most
+contributors aren't able to set these labels.
+
+### Area
+
+The area label describes the crates relevant to this issue or PR.
+
+- **A-ci** This issue concerns our GitHub Actions setup.
+- **A-tokio** This issue concerns the main Tokio crate.
+- **A-readme** This issue is related to documentation such as README.md.
+- **A-benches** This issue concerns the benchmarks.
+- **A-examples** This issue concerns the examples.
+- **A-tokio-test** The issue concerns the `tokio-test` crate.
+- **A-tokio-util** This issue concerns the `tokio-util` crate.
+- **A-tokio-macros** This issue concerns the `tokio-macros` crate. Should only
+  be used for the procedural macros, and not `join!` or `select!`.
+- **A-tokio-stream** This issue concerns the `tokio-stream` crate.
+
+### Category
+
+- **C-bug** This is a bug-report. Bug-fix PRs use `C-enhancement` instead.
+- **C-enhancement** This is a PR that adds a new features.
+- **C-maintenance** This is an issue or PR about stuff such as documentation,
+  GitHub Actions or code quality.
+- **C-feature-request** This is a feature request. Implementations of feature
+  requests use `C-enhancement` instead.
+- **C-feature-accepted** If you submit a PR for this feature request, we won't
+  close it with the reason "we don't want this". Issues with this label should
+  also have the `C-feature-request` label.
+- **C-musing** Stuff like tracking issues or roadmaps. "musings about a better
+  world"
+- **C-proposal** A proposal of some kind, and a request for comments.
+- **C-question** A user question. Large overlap with GitHub discussions.
+- **C-request** A non-feature request, e.g. "please add deprecation notices to
+  `-alpha.*` versions of crates"
+
+### Calls for participation
+
+- **E-help-wanted** Stuff where we want help. Often seen together with `C-bug`
+  or `C-feature-accepted`.
+- **E-easy** This is easy, ranging from quick documentation fixes to stuff you
+  can do after reading the tutorial on our website.
+- **E-medium** This is not `E-easy` or `E-hard`.
+- **E-hard** This either involves very tricky code, is something we don't know
+  how to solve, or is challenging for some other reason.
+- **E-needs-mvce** This bug is missing a minimal complete and verifiable
+  example.
+
+The "E-" prefix is the same as used in the Rust compiler repository. Some
+issues are missing a difficulty rating, but feel free to ask on our Discord
+server if you want to know how challenging an issue likely is.
+
+### Module
+
+The module label provides a more fine grained categorization than **Area**.
+
+- **M-blocking** Things relevant to `spawn_blocking`, `block_in_place`.
+- **M-codec** The `tokio_util::codec` module.
+- **M-compat** The `tokio_util::compat` module.
+- **M-coop** Things relevant to coop.
+- **M-fs** The `tokio::fs` module.
+- **M-io** The `tokio::io` module.
+- **M-macros** Issues about any kind of macro.
+- **M-metrics** Things relevant to `tokio::runtime::metrics`.
+- **M-net** The `tokio::net` module.
+- **M-process** The `tokio::process` module.
+- **M-runtime** The `tokio::runtime` module.
+- **M-signal** The `tokio::signal` module.
+- **M-sync** The `tokio::sync` module.
+- **M-task** The `tokio::task` module.
+- **M-time** The `tokio::time` module.
+- **M-tracing** Tracing support in Tokio.
+- **M-taskdump** Things relevant to taskdump.
+
+### Topic
+
+Some extra information.
+
+- **T-docs** This is about documentation.
+- **T-io-uring** This is about io-uring (Linux).
+- **T-performance** This is about performance.
+- **T-v0.1.x** This is about old Tokio.
+- **T-wasm** This is about Web Assembly.
+
+Any label not listed here is not in active use.
+
+[project]: https://github.com/orgs/tokio-rs/projects/1

docs/contributing/pull-requests.md

@@ -0,0 +1,350 @@
+## Pull Requests
+
+Pull Requests are the way concrete changes are made to the code, documentation,
+and dependencies in the Tokio repository.
+
+Even tiny pull requests (e.g., one-character pull request fixing a typo in API
+documentation) are greatly appreciated.
+
+> [!NOTE]
+> Before making a large change, it is usually a good idea to first open an
+> issue describing the change to solicit feedback and guidance.
+> This will increase the likelihood of the PR getting merged.
+
+### Cargo Commands
+
+Due to the extensive use of features in Tokio, you will often need to add extra
+arguments to many common cargo commands. This section lists some commonly needed
+commands.
+
+Some commands just need the `--all-features` argument:
+
+```
+cargo build --all-features
+cargo check --all-features
+cargo test --all-features
+```
+
+> [!NOTE]
+> There are some features that are not available in some systems (e.g., `io-uring`
+> which is Linux only). In that case you cannot use the `--all-features` and you
+> should specify only the features that are supported (e.g., `--features=full`).
+
+Ideally, you should use the same version of clippy as the one used in CI
+(defined by `env.rust_clippy` in [ci.yml][ci.yml]), because newer versions
+might have new lints:
+
+[ci.yml]: ../../.github/workflows/ci.yml
+
+<!--
+When updating this, also update:
+- .github/workflows/ci.yml
+- README.md
+- tokio/README.md
+- tokio/Cargo.toml
+- tokio-util/Cargo.toml
+- tokio-test/Cargo.toml
+- tokio-stream/Cargo.toml
+-->
+
+```
+cargo +1.88 clippy --all --tests --all-features
+```
+
+When building documentation, a simple `cargo doc` is not sufficient. To produce
+documentation equivalent to what will be produced in docs.rs's builds of Tokio's
+docs, please use:
+
+```
+RUSTDOCFLAGS="--cfg docsrs --cfg tokio_unstable" RUSTFLAGS="--cfg docsrs --cfg tokio_unstable" cargo +nightly doc --all-features [--open]
+```
+
+This turns on indicators to display the Cargo features required for
+conditionally compiled APIs in Tokio, and it enables documentation of unstable
+Tokio features. Notice that it is necessary to pass cfg flags to both RustDoc
+*and* rustc.
+
+There is a more concise way to build docs.rs-equivalent docs by using [`cargo
+docs-rs`], which reads the above documentation flags out of Tokio's Cargo.toml
+as docs.rs itself does.
+
+[`cargo docs-rs`]: https://github.com/dtolnay/cargo-docs-rs
+
+```
+cargo install --locked cargo-docs-rs
+cargo +nightly docs-rs [--open]
+```
+
+The `cargo fmt` command does not work on the Tokio codebase. You can use the
+command below instead:
+
+```
+# Mac or Linux
+rustfmt --check --edition 2021 $(git ls-files '*.rs')
+
+# Powershell
+Get-ChildItem . -Filter "*.rs" -Recurse | foreach { rustfmt --check --edition 2021 $_.FullName }
+```
+The `--check` argument prints the things that need to be fixed. If you remove
+it, `rustfmt` will update your files locally instead.
+
+You can run loom tests with
+```
+cd tokio # tokio crate in workspace
+LOOM_MAX_PREEMPTIONS=1 LOOM_MAX_BRANCHES=10000 RUSTFLAGS="--cfg loom -C debug_assertions" \
+    cargo test --lib --release --features full -- --test-threads=1 --nocapture
+```
+Additionally, you can also add `--cfg tokio_unstable` to the `RUSTFLAGS` environment variable to
+run loom tests that test unstable features.
+
+You can run miri tests with
+```
+MIRIFLAGS="-Zmiri-disable-isolation -Zmiri-strict-provenance" \
+    cargo +nightly miri test --features full --lib --tests
+```
+
+### Performing spellcheck on Tokio codebase
+
+You can perform a spell-check on the Tokio codebase. For details of how to use the spellcheck tool, feel free to visit
+https://github.com/drahnr/cargo-spellcheck
+```
+# First install the spell-check plugin
+cargo install --locked cargo-spellcheck
+
+# Then run the cargo spell check command
+cargo spellcheck check
+```
+
+If the command rejects a word, you should backtick the rejected word if it's code related. If not, the
+rejected word should be put into `spellcheck.dic` file.
+
+Note that when you add a word into the file, you should also update the first line which tells the spellcheck tool
+the total number of words included in the file
+
+### Tests
+
+If the change being proposed alters code (as opposed to only documentation for
+example), it is either adding new functionality to Tokio or it is fixing
+existing, broken functionality. In both of these cases, the pull request should
+include one or more tests to ensure that Tokio does not regress in the future.
+There are two ways to write tests: [integration tests][integration-tests]
+and [documentation tests][documentation-tests].
+(Tokio avoids [unit tests][unit-tests] as much as possible).
+
+Tokio uses [conditional compilation attributes][conditional-compilation]
+throughout the codebase, to modify rustc's behavior. Code marked with such
+attributes can be enabled using `RUSTFLAGS` and `RUSTDOCFLAGS` environment
+variables. One of the most prevalent flags passed in these variables is
+the `--cfg` option. To run tests in a particular file, check first what
+options #![cfg] declaration defines for that file.
+
+For instance, to run a test marked with the 'tokio_unstable' cfg option,
+you must pass this flag to the compiler when running the test.
+```
+$ RUSTFLAGS="--cfg tokio_unstable" cargo test -p tokio --all-features --test rt_metrics
+```
+
+#### Integration tests
+
+Integration tests go in the same crate as the code they are testing. Each sub
+crate should have a `dev-dependency` on `tokio` itself. This makes all Tokio
+utilities available to use in tests, no matter the crate being tested.
+
+The best strategy for writing a new integration test is to look at existing
+integration tests in the crate and follow the style.
+
+#### Fuzz tests
+
+Some of our crates include a set of fuzz tests, this will be marked by a
+directory `fuzz`. It is a good idea to run fuzz tests after each change.
+To get started with fuzz testing you'll need to install
+[cargo-fuzz](https://github.com/rust-fuzz/cargo-fuzz).
+
+`cargo install --locked cargo-fuzz`
+
+To list the available fuzzing harnesses you can run;
+
+```bash
+$ cd tokio
+$ cargo fuzz list
+fuzz_linked_list
+```
+
+Running a fuzz test is as simple as;
+
+`cargo fuzz run fuzz_linked_list`
+
+**NOTE**: Keep in mind that by default when running a fuzz test the fuzz
+harness will run forever and will only exit if you `ctrl-c` or it finds
+a bug.
+
+#### Documentation tests
+
+Ideally, every API has at least one [documentation test] that demonstrates how to
+use the API. Documentation tests are run with `cargo test --doc`. This ensures
+that the example is correct and provides additional test coverage.
+
+The trick to documentation tests is striking a balance between being succinct
+for a reader to understand and actually testing the API.
+
+Same as with integration tests, when writing a documentation test, the full
+`tokio` crate is available. This is especially useful for getting access to the
+runtime to run the example.
+
+The documentation tests will be visible from both the crate-specific
+documentation **and** the `tokio` facade documentation via the re-export. The
+example should be written from the point of view of a user that is using the
+`tokio` crate. As such, the example should use the API via the facade and not by
+directly referencing the crate.
+
+The type level example for `tokio::time::timeout` provides a good example of a
+documentation test:
+
+```
+/// Create a new `Timeout` set to expire in 10 milliseconds.
+///
+/// ```rust
+/// use tokio::time::timeout;
+/// use tokio::sync::oneshot;
+///
+/// use std::time::Duration;
+///
+/// # async fn dox() {
+/// let (tx, rx) = oneshot::channel();
+/// # tx.send(()).unwrap();
+///
+/// // Wrap the future with a `Timeout` set to expire in 10 milliseconds.
+/// if let Err(_) = timeout(Duration::from_millis(10), rx).await {
+///     println!("did not receive value within 10 ms");
+/// }
+/// # }
+/// ```
+```
+
+Lines that start with `/// #` are removed when the documentation is generated.
+
+### Benchmarks
+
+You can run benchmarks locally for the changes you've made to the tokio codebase.
+Tokio currently uses [Criterion](https://github.com/bheisler/criterion.rs) as its benchmarking tool. To run a benchmark
+against the changes you have made, for example, you can run;
+
+```bash
+cd benches
+
+# Run all benchmarks.
+cargo bench
+
+# Run all tests in the `benches/fs.rs` file
+cargo bench --bench fs
+
+# Run the `async_read_buf` benchmark in `benches/fs.rs` specifically.
+cargo bench async_read_buf
+
+# After running benches, you can check the statistics under `tokio/target/criterion/`
+```
+
+You can also refer to [Criterion] docs for additional options and details.
+
+[Criterion]: https://docs.rs/criterion/latest/criterion/
+
+### Commits
+
+It is a recommended best practice to keep your changes as logically grouped as
+possible within individual commits. There is no limit to the number of commits
+any single Pull Request may have, and many contributors find it easier to review
+changes that are split across multiple commits.
+
+That said, if you have a number of commits that are "checkpoints" and don't
+represent a single logical change, please squash those together.
+
+Note that multiple commits often get squashed when they are landed (see the
+notes about [commit squashing](#commit-squashing)).
+
+#### Commit message guidelines
+
+A good commit message should describe what changed and why.
+
+1. The first line should:
+
+* contain a short description of the change (preferably 50 characters or less,
+  and no more than 72 characters)
+* be entirely in lowercase with the exception of proper nouns, acronyms, and
+  the words that refer to code, like function/variable names
+* start with an imperative verb
+* not have a period at the end
+* be prefixed with the name of the module being changed; usually this is the
+  same as the M-* label on the PR
+
+Examples:
+
+* time: introduce `Timeout` and deprecate `Deadline`
+* codec: export `Encoder`, `Decoder`, `Framed*`
+* ci: fix the FreeBSD ci configuration
+
+2. Keep the second line blank.
+3. Wrap all other lines at 72 columns (except for long URLs).
+4. If your patch fixes an open issue, you can add a reference to it at the end
+   of the log. Use the `Fixes: #` prefix and the issue number. For other
+   references use `Refs: #`. `Refs` may include multiple issues, separated by a
+   comma.
+
+   Examples:
+
+    - `Fixes: #1337`
+    - `Refs: #1234`
+
+Sample complete commit message:
+
+```txt
+module: explain the commit in one line
+
+Body of commit message is a few lines of text, explaining things
+in more detail, possibly giving some background about the issue
+being fixed, etc.
+
+The body of the commit message can be several paragraphs, and
+please do proper word-wrap and keep columns shorter than about
+72 characters or so. That way, `git log` will show things
+nicely even when it is indented.
+
+Fixes: #1337
+Refs: #453, #154
+```
+
+### Opening the Pull Request
+
+From within GitHub, opening a new Pull Request will present you with a
+[template] that should be filled out. Please try to do your best at filling out
+the details, but feel free to skip parts if you're not sure what to put.
+
+[template]: ../../.github/PULL_REQUEST_TEMPLATE.md
+
+### Discuss and update
+
+You will probably get feedback or requests for changes to your Pull Request.
+This is a big part of the submission process so don't be discouraged! Some
+contributors may sign off on the Pull Request right away, others may have
+more detailed comments or feedback. This is a necessary part of the process
+in order to evaluate whether the changes are correct and necessary.
+
+**Any community member can review a PR and you might get conflicting feedback**.
+Keep an eye out for comments from code owners to provide guidance on conflicting
+feedback.
+
+**Once the PR is open, do not rebase the commits**. See [Commit Squashing](#commit-squashing) for
+more details.
+
+### Commit Squashing
+
+In most cases, **do not squash commits that you add to your Pull Request during
+the review process**. When the commits in your Pull Request land, they may be
+squashed into one commit per logical change. Metadata will be added to the
+commit message (including links to the Pull Request, links to relevant issues,
+and the names of the reviewers). The commit history of your Pull Request,
+however, will stay intact on the Pull Request page.
+
+[integration-tests]: https://doc.rust-lang.org/rust-by-example/testing/integration_testing.html
+[unit-tests]: https://doc.rust-lang.org/rust-by-example/testing/unit_testing.html
+[documentation-tests]: https://doc.rust-lang.org/rust-by-example/testing/doc_testing.html
+[conditional-compilation]: https://doc.rust-lang.org/reference/conditional-compilation.html

docs/contributing/reviewing-pull-requests.md

@@ -0,0 +1,80 @@
+## Reviewing Pull Requests
+
+**Any Tokio community member is welcome to review any pull request**.
+
+All Tokio contributors who choose to review and provide feedback on Pull
+Requests have a responsibility to both the project and the individual making the
+contribution. Reviews and feedback must be helpful, insightful, and geared
+towards improving the contribution as opposed to simply blocking it. If there
+are reasons why you feel the PR should not land, explain what those are. Do not
+expect to be able to block a Pull Request from advancing simply because you say
+"No" without giving an explanation. Be open to having your mind changed. Be open
+to working with the contributor to make the Pull Request better.
+
+Reviews that are dismissive or disrespectful of the contributor or any other
+reviewers are strictly counter to the Code of Conduct.
+
+When reviewing a Pull Request, the primary goals are for the codebase to improve
+and for the person submitting the request to succeed. **Even if a Pull Request
+does not land, the submitters should come away from the experience feeling like
+their effort was not wasted or unappreciated**. Every Pull Request from a new
+contributor is an opportunity to grow the community.
+
+### Review a bit at a time
+
+Do not overwhelm new contributors.
+
+It is tempting to micro-optimize and make everything about relative performance,
+perfect grammar, or exact style matches. Do not succumb to that temptation.
+
+Focus first on the most significant aspects of the change:
+
+1. Does this change make sense for Tokio?
+2. Does this change make Tokio better, even if only incrementally?
+3. Are there clear bugs or larger scale issues that need attending to?
+4. Is the commit message readable and correct? If it contains a breaking change
+   is it clear enough?
+
+Note that only **incremental** improvement is needed to land a PR. This means
+that the PR does not need to be perfect, only better than the status quo. Follow
+up PRs may be opened to continue iterating.
+
+When changes are necessary, *request* them, do not *demand* them, and **do not
+assume that the submitter already knows how to add a test or run a benchmark**.
+
+Specific performance optimization techniques, coding styles and conventions
+change over time. The first impression you give to a new contributor never does.
+
+Nits (requests for small changes that are not essential) are fine, but try to
+avoid stalling the Pull Request. Most nits can typically be fixed by the Tokio
+Collaborator landing the Pull Request but they can also be an opportunity for
+the contributor to learn a bit more about the project.
+
+It is always good to clearly indicate nits when you comment: e.g.
+`Nit: change foo() to bar(). But this is not blocking.`
+
+If your comments were addressed but were not folded automatically after new
+commits or if they proved to be mistaken, please, [hide them][hiding-a-comment]
+with the appropriate reason to keep the conversation flow concise and relevant.
+
+### Be aware of the person behind the code
+
+Be aware that *how* you communicate requests and reviews in your feedback can
+have a significant impact on the success of the Pull Request. Yes, we may land
+a particular change that makes Tokio better, but the individual might just not
+want to have anything to do with Tokio ever again. The goal is not just having
+good code.
+
+### Abandoned or Stalled Pull Requests
+
+If a Pull Request appears to be abandoned or stalled, it is polite to first
+check with the contributor to see if they intend to continue the work before
+checking if they would mind if you took it over (especially if it just has nits
+left). When doing so, it is courteous to give the original contributor credit
+for the work they started (either by preserving their name and email address in
+the commit log, or by using an `Author: ` meta-data tag in the commit.
+
+_Adapted from the [Node.js contributing guide][node]_.
+
+[node]: https://github.com/nodejs/node/blob/master/CONTRIBUTING.md
+[hiding-a-comment]: https://help.github.com/articles/managing-disruptive-comments/#hiding-a-comment

examples/Cargo.toml

@@ -16,34 +16,47 @@ tracing = "0.1"
 tracing-subscriber = { version = "0.3.1", default-features = false, features = ["fmt", "ansi", "env-filter", "tracing-log"] }
 bytes = "1.0.0"
 futures = { version = "0.3.0", features = ["thread-pool"]}
-http = "0.2"
+http = "1"
 serde = "1.0"
 serde_derive = "1.0"
 serde_json = "1.0"
 httparse = "1.0"
 httpdate = "1.0"
 once_cell = "1.5.2"
-rand = "0.8.3"
+
+[target.'cfg(target_os = "linux")'.dev-dependencies]
+libc = "0.2"
+
+[target.'cfg(all(tokio_unstable, target_os = "linux"))'.dev-dependencies]
+tokio = { version = "1.0.0", path = "../tokio", features = ["full", "tracing", "taskdump"] }
 
 [target.'cfg(windows)'.dev-dependencies.windows-sys]
-version = "0.52"
+version = "0.61"
 
 [[example]]
 name = "chat"
 path = "chat.rs"
 
 [[example]]
-name = "connect"
-path = "connect.rs"
+name = "connect-tcp"
+path = "connect-tcp.rs"
+
+[[example]]
+name = "connect-udp"
+path = "connect-udp.rs"
+
+[[example]]
+name = "echo-tcp"
+path = "echo-tcp.rs"
+
+[[example]]
+name = "graceful-shutdown"
+path = "graceful-shutdown.rs"
 
 [[example]]
 name = "echo-udp"
 path = "echo-udp.rs"
 
-[[example]]
-name = "echo"
-path = "echo.rs"
-
 [[example]]
 name = "hello_world"
 path = "hello_world.rs"
@@ -96,5 +109,9 @@ path = "named-pipe-multi-client.rs"
 name = "dump"
 path = "dump.rs"
 
+[[example]]
+name = "prewarm-fd-table"
+path = "prewarm-fd-table.rs"
+
 [lints]
 workspace = true

examples/README.md

@@ -10,7 +10,7 @@ cargo run --example $name
 ```
 
 A good starting point for the examples would be [`hello_world`](hello_world.rs)
-and [`echo`](echo.rs). Additionally [the tokio website][tokioweb] contains
+and [`echo-tcp`](echo-tcp.rs). Additionally [the tokio website][tokioweb] contains
 additional guides for some of the examples.
 
 For a larger "real world" example, see the [`mini-redis`][redis] repository.

examples/chat.rs

@@ -39,6 +39,8 @@ use std::io;
 use std::net::SocketAddr;
 use std::sync::Arc;
 
+const DEFAULT_ADDR: &str = "127.0.0.1:6142";
+
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn Error>> {
     use tracing_subscriber::{fmt::format::FmtSpan, EnvFilter};
@@ -70,14 +72,14 @@ async fn main() -> Result<(), Box<dyn Error>> {
 
     let addr = env::args()
         .nth(1)
-        .unwrap_or_else(|| "127.0.0.1:6142".to_string());
+        .unwrap_or_else(|| DEFAULT_ADDR.to_string());
 
     // Bind a TCP listener to the socket address.
     //
     // Note that this is the Tokio TcpListener, which is fully async.
     let listener = TcpListener::bind(&addr).await?;
 
-    tracing::info!("server running on {}", addr);
+    tracing::info!("server running on {addr}");
 
     loop {
         // Asynchronously wait for an inbound TcpStream.
@@ -88,9 +90,9 @@ async fn main() -> Result<(), Box<dyn Error>> {
 
         // Spawn our handler to be run asynchronously.
         tokio::spawn(async move {
-            tracing::debug!("accepted connection");
+            tracing::debug!("accepted connection from {addr}");
             if let Err(e) = process(state, stream, addr).await {
-                tracing::info!("an error occurred; error = {:?}", e);
+                tracing::warn!("Connection from {addr} failed: {e:?}");
             }
         });
     }
@@ -138,12 +140,24 @@ impl Shared {
 
     /// Send a `LineCodec` encoded message to every peer, except
     /// for the sender.
+    ///
+    /// This function also cleans up disconnected peers automatically.
     async fn broadcast(&mut self, sender: SocketAddr, message: &str) {
-        for peer in self.peers.iter_mut() {
-            if *peer.0 != sender {
-                let _ = peer.1.send(message.into());
+        let mut failed_peers = Vec::new();
+        let message = message.to_string(); // Clone once for all sends
+
+        for (addr, tx) in self.peers.iter() {
+            if *addr != sender && tx.send(message.clone()).is_err() {
+                // Receiver has been dropped, mark for removal
+                failed_peers.push(*addr);
             }
         }
+
+        // Clean up disconnected peers
+        for addr in failed_peers {
+            self.peers.remove(&addr);
+            tracing::debug!("Removed disconnected peer: {addr}");
+        }
     }
 }
 
@@ -178,13 +192,10 @@ async fn process(
     lines.send("Please enter your username:").await?;
 
     // Read the first line from the `LineCodec` stream to get the username.
-    let username = match lines.next().await {
-        Some(Ok(line)) => line,
+    let Some(Ok(username)) = lines.next().await else {
         // We didn't get a line so we return early here.
-        _ => {
-            tracing::error!("Failed to get username from {}. Client disconnected.", addr);
-            return Ok(());
-        }
+        tracing::error!("Failed to get username from {addr}. Client disconnected.");
+        return Ok(());
     };
 
     // Register our peer with state which internally sets up some channels.
@@ -194,7 +205,7 @@ async fn process(
     {
         let mut state = state.lock().await;
         let msg = format!("{username} has joined the chat");
-        tracing::info!("{}", msg);
+        tracing::info!("{msg}");
         state.broadcast(addr, &msg).await;
     }
 
@@ -203,7 +214,10 @@ async fn process(
         tokio::select! {
             // A message was received from a peer. Send it to the current user.
             Some(msg) = peer.rx.recv() => {
-                peer.lines.send(&msg).await?;
+                if let Err(e) = peer.lines.send(&msg).await {
+                    tracing::error!("Failed to send message to {username}: {e:?}");
+                    break;
+                }
             }
             result = peer.lines.next() => match result {
                 // A message was received from the current user, we should
@@ -217,10 +231,9 @@ async fn process(
                 // An error occurred.
                 Some(Err(e)) => {
                     tracing::error!(
-                        "an error occurred while processing messages for {}; error = {:?}",
-                        username,
-                        e
+                        "an error occurred while processing messages for {username}; error = {e:?}"
                     );
+                    break;
                 }
                 // The stream has been exhausted.
                 None => break,
@@ -235,7 +248,7 @@ async fn process(
         state.peers.remove(&addr);
 
         let msg = format!("{username} has left the chat");
-        tracing::info!("{}", msg);
+        tracing::info!("{msg}");
         state.broadcast(addr, &msg).await;
     }
 

examples/connect-tcp.rs

@@ -0,0 +1,73 @@
+//! An example of hooking up stdin/stdout to a TCP stream.
+//!
+//! This example will connect to a socket address specified in the argument list
+//! and then forward all data read on stdin to the server, printing out all data
+//! received on stdout. Each line entered on stdin will be translated to a TCP
+//! packet which is then sent to the remote address.
+//!
+//! Note that this is not currently optimized for performance, especially
+//! around buffer management. Rather it's intended to show an example of
+//! working with a client.
+//!
+//! This example can be quite useful when interacting with the other examples in
+//! this repository! Many of them recommend running this as a simple "hook up
+//! stdin/stdout to a server" to get up and running.
+
+#![warn(rust_2018_idioms)]
+
+use tokio::io::{stdin, stdout};
+use tokio::net::TcpStream;
+use tokio_util::codec::{BytesCodec, FramedRead, FramedWrite};
+
+use bytes::Bytes;
+use futures::{future, Sink, SinkExt, Stream, StreamExt};
+use std::env;
+use std::error::Error;
+use std::net::SocketAddr;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn Error>> {
+    // Parse what address we're going to connect to
+    let args = env::args().skip(1).collect::<Vec<_>>();
+    let addr = args
+        .first()
+        .ok_or("this program requires at least one argument")?;
+    let addr = addr.parse::<SocketAddr>()?;
+
+    let stdin = FramedRead::new(stdin(), BytesCodec::new());
+    let stdin = stdin.map(|i| i.map(|bytes| bytes.freeze()));
+    let stdout = FramedWrite::new(stdout(), BytesCodec::new());
+
+    connect(&addr, stdin, stdout).await?;
+
+    Ok(())
+}
+
+pub async fn connect(
+    addr: &SocketAddr,
+    mut stdin: impl Stream<Item = Result<Bytes, std::io::Error>> + Unpin,
+    mut stdout: impl Sink<Bytes, Error = std::io::Error> + Unpin,
+) -> Result<(), Box<dyn Error>> {
+    let mut stream = TcpStream::connect(addr).await?;
+    let (r, w) = stream.split();
+    let mut sink = FramedWrite::new(w, BytesCodec::new());
+    // filter map Result<BytesMut, Error> stream into just a Bytes stream to match stdout Sink
+    // on the event of an Error, log the error and end the stream
+    let mut stream = FramedRead::new(r, BytesCodec::new())
+        .filter_map(|i| match i {
+            //BytesMut into Bytes
+            Ok(i) => future::ready(Some(i.freeze())),
+            Err(e) => {
+                eprintln!("failed to read from socket; error={e}");
+                future::ready(None)
+            }
+        })
+        .map(Ok);
+
+    tokio::select! {
+        r = sink.send_all(&mut stdin) => r?,
+        r = stdout.send_all(&mut stream) => r?,
+    }
+
+    Ok(())
+}

examples/connect-udp.rs

@@ -0,0 +1,94 @@
+//! An example of hooking up stdin/stdout to a UDP stream.
+//!
+//! This example will connect to a socket address specified in the argument list
+//! and then forward all data read on stdin to the server, printing out all data
+//! received on stdout. Each line entered on stdin will be translated to a UDP
+//! packet which is then sent to the remote address.
+//!
+//! Note that this is not currently optimized for performance, especially
+//! around buffer management. Rather it's intended to show an example of
+//! working with a client.
+//!
+//! This example can be quite useful when interacting with the other examples in
+//! this repository! Many of them recommend running this as a simple "hook up
+//! stdin/stdout to a server" to get up and running.
+
+#![warn(rust_2018_idioms)]
+
+use tokio::io::{stdin, stdout};
+use tokio::net::UdpSocket;
+use tokio_util::codec::{BytesCodec, FramedRead, FramedWrite};
+
+use bytes::Bytes;
+use futures::{Sink, SinkExt, Stream, StreamExt};
+use std::env;
+use std::error::Error;
+use std::net::SocketAddr;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn Error>> {
+    // Parse what address we're going to connect to
+    let args = env::args().skip(1).collect::<Vec<_>>();
+    let addr = args
+        .first()
+        .ok_or("this program requires at least one argument")?;
+    let addr = addr.parse::<SocketAddr>()?;
+
+    let stdin = FramedRead::new(stdin(), BytesCodec::new());
+    let stdin = stdin.map(|i| i.map(|bytes| bytes.freeze()));
+    let stdout = FramedWrite::new(stdout(), BytesCodec::new());
+
+    connect(&addr, stdin, stdout).await?;
+
+    Ok(())
+}
+
+pub async fn connect(
+    addr: &SocketAddr,
+    stdin: impl Stream<Item = Result<Bytes, std::io::Error>> + Unpin,
+    stdout: impl Sink<Bytes, Error = std::io::Error> + Unpin,
+) -> Result<(), Box<dyn Error>> {
+    // We'll bind our UDP socket to a local IP/port, but for now we
+    // basically let the OS pick both of those.
+    let bind_addr = if addr.ip().is_ipv4() {
+        "0.0.0.0:0"
+    } else {
+        "[::]:0"
+    };
+
+    let socket = UdpSocket::bind(&bind_addr).await?;
+    socket.connect(addr).await?;
+
+    tokio::select! {
+        r = send(stdin, &socket) => r?,
+        r = recv(stdout, &socket) => r?,
+    }
+
+    Ok(())
+}
+
+async fn send(
+    mut stdin: impl Stream<Item = Result<Bytes, std::io::Error>> + Unpin,
+    writer: &UdpSocket,
+) -> Result<(), std::io::Error> {
+    while let Some(item) = stdin.next().await {
+        let buf = item?;
+        writer.send(&buf[..]).await?;
+    }
+
+    Ok(())
+}
+
+async fn recv(
+    mut stdout: impl Sink<Bytes, Error = std::io::Error> + Unpin,
+    reader: &UdpSocket,
+) -> Result<(), std::io::Error> {
+    loop {
+        let mut buf = vec![0; 1024];
+        let n = reader.recv(&mut buf[..]).await?;
+
+        if n > 0 {
+            stdout.send(Bytes::copy_from_slice(&buf[..n])).await?;
+        }
+    }
+}

examples/connect.rs

@@ -1,147 +0,0 @@
-//! An example of hooking up stdin/stdout to either a TCP or UDP stream.
-//!
-//! This example will connect to a socket address specified in the argument list
-//! and then forward all data read on stdin to the server, printing out all data
-//! received on stdout. An optional `--udp` argument can be passed to specify
-//! that the connection should be made over UDP instead of TCP, translating each
-//! line entered on stdin to a UDP packet to be sent to the remote address.
-//!
-//! Note that this is not currently optimized for performance, especially
-//! around buffer management. Rather it's intended to show an example of
-//! working with a client.
-//!
-//! This example can be quite useful when interacting with the other examples in
-//! this repository! Many of them recommend running this as a simple "hook up
-//! stdin/stdout to a server" to get up and running.
-
-#![warn(rust_2018_idioms)]
-
-use futures::StreamExt;
-use tokio::io;
-use tokio_util::codec::{BytesCodec, FramedRead, FramedWrite};
-
-use std::env;
-use std::error::Error;
-use std::net::SocketAddr;
-
-#[tokio::main]
-async fn main() -> Result<(), Box<dyn Error>> {
-    // Determine if we're going to run in TCP or UDP mode
-    let mut args = env::args().skip(1).collect::<Vec<_>>();
-    let tcp = match args.iter().position(|a| a == "--udp") {
-        Some(i) => {
-            args.remove(i);
-            false
-        }
-        None => true,
-    };
-
-    // Parse what address we're going to connect to
-    let addr = args
-        .first()
-        .ok_or("this program requires at least one argument")?;
-    let addr = addr.parse::<SocketAddr>()?;
-
-    let stdin = FramedRead::new(io::stdin(), BytesCodec::new());
-    let stdin = stdin.map(|i| i.map(|bytes| bytes.freeze()));
-    let stdout = FramedWrite::new(io::stdout(), BytesCodec::new());
-
-    if tcp {
-        tcp::connect(&addr, stdin, stdout).await?;
-    } else {
-        udp::connect(&addr, stdin, stdout).await?;
-    }
-
-    Ok(())
-}
-
-mod tcp {
-    use bytes::Bytes;
-    use futures::{future, Sink, SinkExt, Stream, StreamExt};
-    use std::{error::Error, io, net::SocketAddr};
-    use tokio::net::TcpStream;
-    use tokio_util::codec::{BytesCodec, FramedRead, FramedWrite};
-
-    pub async fn connect(
-        addr: &SocketAddr,
-        mut stdin: impl Stream<Item = Result<Bytes, io::Error>> + Unpin,
-        mut stdout: impl Sink<Bytes, Error = io::Error> + Unpin,
-    ) -> Result<(), Box<dyn Error>> {
-        let mut stream = TcpStream::connect(addr).await?;
-        let (r, w) = stream.split();
-        let mut sink = FramedWrite::new(w, BytesCodec::new());
-        // filter map Result<BytesMut, Error> stream into just a Bytes stream to match stdout Sink
-        // on the event of an Error, log the error and end the stream
-        let mut stream = FramedRead::new(r, BytesCodec::new())
-            .filter_map(|i| match i {
-                //BytesMut into Bytes
-                Ok(i) => future::ready(Some(i.freeze())),
-                Err(e) => {
-                    println!("failed to read from socket; error={e}");
-                    future::ready(None)
-                }
-            })
-            .map(Ok);
-
-        match future::join(sink.send_all(&mut stdin), stdout.send_all(&mut stream)).await {
-            (Err(e), _) | (_, Err(e)) => Err(e.into()),
-            _ => Ok(()),
-        }
-    }
-}
-
-mod udp {
-    use bytes::Bytes;
-    use futures::{Sink, SinkExt, Stream, StreamExt};
-    use std::error::Error;
-    use std::io;
-    use std::net::SocketAddr;
-    use tokio::net::UdpSocket;
-
-    pub async fn connect(
-        addr: &SocketAddr,
-        stdin: impl Stream<Item = Result<Bytes, io::Error>> + Unpin,
-        stdout: impl Sink<Bytes, Error = io::Error> + Unpin,
-    ) -> Result<(), Box<dyn Error>> {
-        // We'll bind our UDP socket to a local IP/port, but for now we
-        // basically let the OS pick both of those.
-        let bind_addr = if addr.ip().is_ipv4() {
-            "0.0.0.0:0"
-        } else {
-            "[::]:0"
-        };
-
-        let socket = UdpSocket::bind(&bind_addr).await?;
-        socket.connect(addr).await?;
-
-        tokio::try_join!(send(stdin, &socket), recv(stdout, &socket))?;
-
-        Ok(())
-    }
-
-    async fn send(
-        mut stdin: impl Stream<Item = Result<Bytes, io::Error>> + Unpin,
-        writer: &UdpSocket,
-    ) -> Result<(), io::Error> {
-        while let Some(item) = stdin.next().await {
-            let buf = item?;
-            writer.send(&buf[..]).await?;
-        }
-
-        Ok(())
-    }
-
-    async fn recv(
-        mut stdout: impl Sink<Bytes, Error = io::Error> + Unpin,
-        reader: &UdpSocket,
-    ) -> Result<(), io::Error> {
-        loop {
-            let mut buf = vec![0; 1024];
-            let n = reader.recv(&mut buf[..]).await?;
-
-            if n > 0 {
-                stdout.send(Bytes::from(buf)).await?;
-            }
-        }
-    }
-}

examples/dump.rs

@@ -4,7 +4,6 @@
 
 #[cfg(all(
     tokio_unstable,
-    tokio_taskdump,
     target_os = "linux",
     any(target_arch = "aarch64", target_arch = "x86", target_arch = "x86_64")
 ))]
@@ -82,7 +81,6 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 
 #[cfg(not(all(
     tokio_unstable,
-    tokio_taskdump,
     target_os = "linux",
     any(target_arch = "aarch64", target_arch = "x86", target_arch = "x86_64")
 )))]

examples/echo-tcp.rs

@@ -9,14 +9,14 @@
 //!
 //! To see this server in action, you can run this in one terminal:
 //!
-//!     cargo run --example echo
+//!     cargo run --example echo-tcp
 //!
 //! and in another terminal you can run:
 //!
-//!     cargo run --example connect 127.0.0.1:8080
+//!     cargo run --example connect-tcp 127.0.0.1:8080
 //!
-//! Each line you type in to the `connect` terminal should be echo'd back to
-//! you! If you open up multiple terminals running the `connect` example you
+//! Each line you type in to the `connect-tcp` terminal should be echo'd back to
+//! you! If you open up multiple terminals running the `connect-tcp` example you
 //! should be able to see them all make progress simultaneously.
 
 #![warn(rust_2018_idioms)]
@@ -27,6 +27,9 @@ use tokio::net::TcpListener;
 use std::env;
 use std::error::Error;
 
+const DEFAULT_ADDR: &str = "127.0.0.1:8080";
+const BUFFER_SIZE: usize = 4096;
+
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn Error>> {
     // Allow passing an address to listen on as the first argument of this
@@ -34,7 +37,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
     // 127.0.0.1:8080 for connections.
     let addr = env::args()
         .nth(1)
-        .unwrap_or_else(|| "127.0.0.1:8080".to_string());
+        .unwrap_or_else(|| DEFAULT_ADDR.to_string());
 
     // Next up we create a TCP listener which will listen for incoming
     // connections. This TCP listener is bound to the address we determined
@@ -44,7 +47,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
 
     loop {
         // Asynchronously wait for an inbound socket.
-        let (mut socket, _) = listener.accept().await?;
+        let (mut socket, addr) = listener.accept().await?;
 
         // And this is where much of the magic of this server happens. We
         // crucially want all clients to make progress concurrently, rather than
@@ -55,23 +58,27 @@ async fn main() -> Result<(), Box<dyn Error>> {
         // which will allow all of our clients to be processed concurrently.
 
         tokio::spawn(async move {
-            let mut buf = vec![0; 1024];
+            let mut buf = vec![0; BUFFER_SIZE];
 
             // In a loop, read data from the socket and write the data back.
             loop {
-                let n = socket
-                    .read(&mut buf)
-                    .await
-                    .expect("failed to read data from socket");
-
-                if n == 0 {
-                    return;
+                match socket.read(&mut buf).await {
+                    Ok(0) => {
+                        // Connection closed by peer
+                        return;
+                    }
+                    Ok(n) => {
+                        // Write the data back. If writing fails, log the error and exit.
+                        if let Err(e) = socket.write_all(&buf[0..n]).await {
+                            eprintln!("Failed to write to socket {}: {}", addr, e);
+                            return;
+                        }
+                    }
+                    Err(e) => {
+                        eprintln!("Failed to read from socket {}: {}", addr, e);
+                        return;
+                    }
                 }
-
-                socket
-                    .write_all(&buf[0..n])
-                    .await
-                    .expect("failed to write data to socket");
             }
         });
     }

examples/echo-udp.rs

@@ -6,9 +6,9 @@
 //!
 //! and in another terminal you can run:
 //!
-//!     cargo run --example connect -- --udp 127.0.0.1:8080
+//!     cargo run --example connect-udp 127.0.0.1:8080
 //!
-//! Each line you type in to the `nc` terminal should be echo'd back to you!
+//! Each line you type in to the `connect-udp` terminal should be echo'd back to you!
 
 #![warn(rust_2018_idioms)]
 

examples/graceful-shutdown.rs

@@ -0,0 +1,120 @@
+//! Graceful shutdown example.
+//!
+//! This example follows the same approach described in the
+//! [Graceful Shutdown tutorial](https://tokio.rs/tokio/topics/shutdown):
+//!
+//! - A [`CancellationToken`] tells tasks to stop accepting new work.
+//! - A [`TaskTracker`] waits for in-flight work to complete.
+//!
+//! It runs a TCP echo server on `127.0.0.1:6142`. When Ctrl+C is
+//! pressed, the server stops accepting connections and waits for all
+//! active connections to finish before exiting.
+//!
+//! Start the server:
+//!
+//!     cargo run --example graceful-shutdown
+//!
+//! Then connect with:
+//!
+//!     nc 127.0.0.1 6142
+//!
+//! Press Ctrl+C on the server to trigger a graceful shutdown.
+
+#![warn(rust_2018_idioms)]
+
+use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
+use tokio::net::{TcpListener, TcpStream};
+use tokio::time::{self, Duration};
+use tokio_util::sync::CancellationToken;
+use tokio_util::task::TaskTracker;
+
+use std::error::Error;
+use std::net::SocketAddr;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn Error>> {
+    let listener = TcpListener::bind("127.0.0.1:6142").await?;
+    println!("listening on 127.0.0.1:6142");
+
+    let token = CancellationToken::new();
+    let tracker = TaskTracker::new();
+
+    loop {
+        tokio::select! {
+            result = listener.accept() => {
+                let (socket, addr) = match result {
+                    Ok(conn) => conn,
+                    Err(e) => {
+                        // Transient errors (e.g. fd exhaustion) are recoverable,
+                        // so we log and continue. A production server might add a
+                        // backoff or break on fatal errors to avoid a busy loop.
+                        eprintln!("failed to accept: {e}");
+                        continue;
+                    }
+                };
+                println!("accepted connection from {addr}");
+
+                let token = token.clone();
+                tracker.spawn(handle_connection(socket, addr, token));
+            }
+
+            _ = tokio::signal::ctrl_c() => {
+                println!("\nshutdown signal received, waiting for connections to finish");
+                break;
+            }
+        }
+    }
+
+    // Signal all tasks to stop and wait for them to complete.
+    token.cancel();
+    tracker.close();
+    tracker.wait().await;
+
+    println!("shutdown complete");
+    Ok(())
+}
+
+async fn handle_connection(mut socket: TcpStream, addr: SocketAddr, token: CancellationToken) {
+    tokio::select! {
+        _ = echo(&mut socket) => {}
+        _ = token.cancelled() => {
+            notify_shutdown(&mut socket).await;
+        }
+    }
+
+    println!("connection from {addr} closed");
+}
+
+/// Reads lines from the client and writes them back.
+///
+/// Called for every accepted connection. Runs until the client disconnects
+/// or a read/write error occurs.
+async fn echo(socket: &mut TcpStream) {
+    let (reader, mut writer) = socket.split();
+    let mut reader = BufReader::new(reader);
+    let mut line = String::new();
+
+    loop {
+        match reader.read_line(&mut line).await {
+            Ok(0) | Err(_) => return,
+            Ok(_) => {
+                if writer.write_all(line.as_bytes()).await.is_err() {
+                    return;
+                }
+                line.clear();
+            }
+        }
+    }
+}
+
+/// Sends a shutdown notice to the client before closing the connection.
+///
+/// Called when the cancellation token fires. Uses a timeout so that a
+/// slow or unresponsive client cannot hold up the server shutdown.
+async fn notify_shutdown(socket: &mut TcpStream) {
+    let _ = time::timeout(
+        Duration::from_secs(1),
+        socket.write_all(b"server shutting down\n"),
+    )
+    .await;
+}

examples/prewarm-fd-table.rs

@@ -0,0 +1,86 @@
+//! Demonstrates pre-warming the Linux file descriptor table to avoid latency
+//! spikes caused by file descriptor table growth in multi-threaded processes.
+//!
+//! On Linux, the kernel's FD table is grown lazily and protected by RCU
+//! synchronization. In multi-threaded processes, when a syscall like `socket()`
+//! triggers a table resize, the calling thread blocks until all RCU readers
+//! quiesce. This can cause stalls of tens of milliseconds on tokio worker threads,
+//! blocking the entire event loop (not just one task).
+//!
+//! The workaround is to force the kernel to expand the FD table once per process
+//! (before any runtime starts), by duplicating an FD to a high slot and then
+//! closing it. The kernel never shrinks the FD table during a process's lifetime,
+//! so the capacity persists.
+//!
+//! This is most relevant for services that open many connections concurrently
+//! (e.g. HTTP servers, connection pools). The pre-warm target should be at least
+//! your expected peak FD count, and must not exceed `RLIMIT_NOFILE`.
+//!
+//! See: <https://github.com/tokio-rs/tokio/issues/7970>
+//!
+//! Usage:
+//!
+//!     cargo run --example prewarm-fd-table
+
+#![warn(rust_2018_idioms)]
+
+/// Pre-warms the FD table using `fcntl(F_DUPFD_CLOEXEC)` to duplicate an FD
+/// into a high slot, expanding the table in a single syscall. `F_DUPFD_CLOEXEC`
+/// allocates the lowest available FD >= `target`, so it never clobbers an
+/// existing FD.
+#[cfg(target_os = "linux")]
+fn prewarm_fd_table(target: i32) -> std::io::Result<()> {
+    use std::os::unix::io::{FromRawFd, OwnedFd};
+
+    let dev_null = std::fs::File::open("/dev/null")?;
+    let raw = unsafe {
+        libc::fcntl(
+            std::os::unix::io::AsRawFd::as_raw_fd(&dev_null),
+            libc::F_DUPFD_CLOEXEC,
+            target,
+        )
+    };
+    if raw < 0 {
+        return Err(std::io::Error::last_os_error());
+    }
+
+    // Close both FDs. The table capacity persists.
+    let _owned = unsafe { OwnedFd::from_raw_fd(raw) };
+    drop(dev_null);
+
+    Ok(())
+}
+
+/// Fully safe alternative using only stdlib. Requires O(n) syscalls instead of
+/// one, but avoids `unsafe` entirely.
+#[cfg(target_os = "linux")]
+#[allow(dead_code)]
+fn prewarm_fd_table_safe(target: i32) -> std::io::Result<()> {
+    let f = std::fs::File::open("/dev/null")?;
+    let _fds: Vec<_> = (0..target)
+        .map(|_| f.try_clone())
+        .collect::<Result<_, _>>()?;
+    Ok(())
+}
+
+fn main() {
+    #[cfg(target_os = "linux")]
+    {
+        const FD_TARGET: i32 = 10_000;
+
+        println!("Pre-warming FD table to {FD_TARGET} entries...");
+        if let Err(e) = prewarm_fd_table(FD_TARGET) {
+            eprintln!("Warning: failed to pre-warm FD table: {e}");
+        } else {
+            println!("FD table pre-warmed successfully.");
+        }
+    }
+
+    // Build the runtime *after* pre-warming.
+    let rt = tokio::runtime::Builder::new_multi_thread()
+        .enable_all()
+        .build()
+        .unwrap();
+
+    rt.block_on(async {});
+}

examples/print_each_packet.rs

@@ -13,9 +13,9 @@
 //!
 //! and in another terminal you can run:
 //!
-//!     cargo run --example connect 127.0.0.1:8080
+//!     cargo run --example connect-tcp 127.0.0.1:8080
 //!
-//! Each line you type in to the `connect` terminal should be written to terminal!
+//! Each line you type in to the `connect-tcp` terminal should be written to terminal!
 //!
 //! Minimal js example:
 //!

examples/proxy.rs

@@ -11,11 +11,11 @@
 //!
 //! This in another terminal
 //!
-//!     cargo run --example echo
+//!     cargo run --example echo-tcp
 //!
 //! And finally this in another terminal
 //!
-//!     cargo run --example connect 127.0.0.1:8081
+//!     cargo run --example connect-tcp 127.0.0.1:8081
 //!
 //! This final terminal will connect to our proxy, which will in turn connect to
 //! the echo server, and you'll be able to see data flowing between them.

examples/tinydb.rs

@@ -12,14 +12,14 @@
 //!
 //! and next in another windows run:
 //!
-//!     cargo run --example connect 127.0.0.1:8080
+//!     cargo run --example connect-tcp 127.0.0.1:8080
 //!
-//! In the `connect` window you can type in commands where when you hit enter
+//! In the `connect-tcp` window you can type in commands where when you hit enter
 //! you'll get a response from the server for that command. An example session
 //! is:
 //!
 //!
-//!     $ cargo run --example connect 127.0.0.1:8080
+//!     $ cargo run --example connect-tcp 127.0.0.1:8080
 //!     GET foo
 //!     foo = bar
 //!     GET FOOBAR

examples/tinyhttp.rs

@@ -82,9 +82,7 @@ async fn respond(req: Request<()>) -> Result<Response<String>, Box<dyn Error>> {
             String::new()
         }
     };
-    let response = response
-        .body(body)
-        .map_err(|err| io::Error::new(io::ErrorKind::Other, err))?;
+    let response = response.body(body).map_err(io::Error::other)?;
 
     Ok(response)
 }
@@ -160,7 +158,7 @@ impl Decoder for Http {
             let mut r = httparse::Request::new(&mut parsed_headers);
             let status = r.parse(src).map_err(|e| {
                 let msg = format!("failed to parse http request: {e:?}");
-                io::Error::new(io::ErrorKind::Other, msg)
+                io::Error::other(msg)
             })?;
 
             let amt = match status {
@@ -180,8 +178,7 @@ impl Decoder for Http {
                 headers[i] = Some((k, v));
             }
 
-            let method = http::Method::try_from(r.method.unwrap())
-                .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
+            let method = http::Method::try_from(r.method.unwrap()).map_err(io::Error::other)?;
 
             (
                 method,
@@ -191,10 +188,7 @@ impl Decoder for Http {
             )
         };
         if version != 1 {
-            return Err(io::Error::new(
-                io::ErrorKind::Other,
-                "only HTTP/1.1 accepted",
-            ));
+            return Err(io::Error::other("only HTTP/1.1 accepted"));
         }
         let data = src.split_to(amt).freeze();
         let mut ret = Request::builder();
@@ -209,13 +203,11 @@ impl Decoder for Http {
                 None => break,
             };
             let value = HeaderValue::from_bytes(data.slice(v.0..v.1).as_ref())
-                .map_err(|_| io::Error::new(io::ErrorKind::Other, "header decode error"))?;
+                .map_err(|_| io::Error::other("header decode error"))?;
             ret = ret.header(&data[k.0..k.1], value);
         }
 
-        let req = ret
-            .body(())
-            .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
+        let req = ret.body(()).map_err(io::Error::other)?;
         Ok(Some(req))
     }
 }

netlify.toml

@@ -8,9 +8,11 @@
   RUSTDOCFLAGS="""
     --cfg docsrs \
     --cfg tokio_unstable \
-    --cfg tokio_taskdump \
     """
-  RUSTFLAGS="--cfg tokio_unstable --cfg tokio_taskdump --cfg docsrs"
+  RUSTFLAGS="""
+    --cfg docsrs \
+    --cfg tokio_unstable
+    """
 
 [[redirects]]
   from = "/"

spellcheck.dic

@@ -1,4 +1,4 @@
-300
+324
 &
 +
 <
@@ -64,13 +64,19 @@ codec
 codecs
 combinator
 combinators
+condvar
 config
 Config
 connectionless
 coroutines
 cpu
 cpus
+cqe
+CQE
+cqe's
+customizable
 Customizable
+Cygwin
 datagram
 Datagram
 datagrams
@@ -83,6 +89,7 @@ decrementing
 demangled
 dequeued
 dereferenced
+derefs
 deregister
 deregistered
 deregistering
@@ -132,6 +139,7 @@ hashmaps
 HashMaps
 hashsets
 HdrHistogram
+ICMP
 ie
 Illumos
 impl
@@ -158,6 +166,7 @@ Lauck
 libc
 lifecycle
 lifo
+LLVM
 lookups
 macOS
 MacOS
@@ -169,6 +178,7 @@ mio's
 miri
 misconfigured
 mock's
+monomorphization
 mpmc
 mpsc
 multi
@@ -179,15 +189,20 @@ mut
 mutex
 Mutex
 Nagle
+namespace
+NetBSD
 nonblocking
 nondecreasing
 noop
 ntasks
+NTO
+NUMA
 ok
 oneshot
+opcode
+OpenBSD
 ORed
 os
-overweighing
 parker
 parsers
 peekable
@@ -199,8 +214,10 @@ POSIX
 proxied
 qos
 RAII
+RCU
 reallocations
 recv's
+Redox
 refactors
 refcount
 refcounting
@@ -230,6 +247,7 @@ spawner
 Splitter
 spmc
 spsc
+SQE
 src
 stabilised
 startup
@@ -266,6 +284,7 @@ tokio's
 Tokio's
 tuple
 Tuple
+tvOS
 tx
 udp
 UDP
@@ -285,6 +304,7 @@ unsets
 Unsets
 unsynchronized
 untrusted
+uring
 usecases
 Valgrind
 Varghese
@@ -292,10 +312,14 @@ vec
 versa
 versioned
 versioning
+visionOS
 vtable
 waker
 wakers
 Wakers
 wakeup
 wakeups
+WASI
+watchOS
 workstealing
+ZST

stress-test/Cargo.toml

@@ -12,7 +12,7 @@ publish = false
 tokio = { version = "1.0.0", path = "../tokio/", features = ["full"] }
 
 [dev-dependencies]
-rand = "0.8"
+rand = "0.9"
 
 [lints]
 workspace = true

target-specs/i686-unknown-linux-gnu.json

@@ -4,6 +4,7 @@
   "crt-objects-fallback": "false",
   "crt-static-respected": true,
   "data-layout": "e-m:e-p:32:32-p270:32:32-p271:32:32-p272:64:64-i128:128-f64:32:64-f80:32-n8:16:32-S128",
+  "default-uwtable": true,
   "dynamic-linking": true,
   "env": "gnu",
   "has-rpath": true,
@@ -12,10 +13,10 @@
   "llvm-target": "i686-unknown-linux-gnu",
   "max-atomic-width": 32,
   "metadata": {
-    "description": null,
-    "host_tools": null,
-    "std": null,
-    "tier": null
+    "description": "32-bit Linux (kernel 3.2, glibc 2.17+)",
+    "host_tools": true,
+    "std": true,
+    "tier": 1
   },
   "os": "linux",
   "position-independent-executables": true,
@@ -28,6 +29,7 @@
     ]
   },
   "relro-level": "full",
+  "rustc-abi": "x86-sse2",
   "stack-probes": {
     "kind": "inline"
   },
@@ -42,5 +44,5 @@
   "target-family": [
     "unix"
   ],
-  "target-pointer-width": "32"
+  "target-pointer-width": 32
 }

tests-build/tests/fail/macros_invalid_input.rs

@@ -68,4 +68,7 @@ async fn test_has_second_test_attr_rust_2021() {}
 #[tokio::test]
 async fn test_has_generated_second_test_attr() {}
 
+#[tokio::test(name = 123)]
+async fn test_name_not_string() {}
+
 fn main() {}

tests-build/tests/fail/macros_invalid_input.stderr

@@ -4,7 +4,7 @@ error: the `async` keyword is missing from the function declaration
 6 | fn main_is_not_async() {}
   | ^^
 
-error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`, `unhandled_panic`.
+error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`, `unhandled_panic`, `name`.
  --> tests/fail/macros_invalid_input.rs:8:15
   |
 8 | #[tokio::main(foo)]
@@ -22,13 +22,13 @@ error: the `async` keyword is missing from the function declaration
 15 | fn test_is_not_async() {}
    | ^^
 
-error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`, `unhandled_panic`.
+error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`, `unhandled_panic`, `name`.
   --> tests/fail/macros_invalid_input.rs:17:15
    |
 17 | #[tokio::test(foo)]
    |               ^^^
 
-error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`, `unhandled_panic`
+error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`, `unhandled_panic`, `name`.
   --> tests/fail/macros_invalid_input.rs:20:15
    |
 20 | #[tokio::test(foo = 123)]
@@ -40,7 +40,7 @@ error: Failed to parse value of `flavor` as string.
 23 | #[tokio::test(flavor = 123)]
    |                        ^^^
 
-error: No such runtime flavor `foo`. The runtime flavors are `current_thread` and `multi_thread`.
+error: No such runtime flavor `foo`. The runtime flavors are `current_thread`, `local`, and `multi_thread`.
   --> tests/fail/macros_invalid_input.rs:26:24
    |
 26 | #[tokio::test(flavor = "foo")]
@@ -119,3 +119,9 @@ error: second test attribute is supplied, consider removing or changing the orde
    | ^^^^^^^^^^^^^^
    |
    = note: this error originates in the attribute macro `tokio::test` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: Failed to parse value of `name` as string.
+  --> tests/fail/macros_invalid_input.rs:71:22
+   |
+71 | #[tokio::test(name = 123)]
+   |                      ^^^

tests-build/tests/fail/macros_join.rs

@@ -0,0 +1,42 @@
+use tests_build::tokio;
+
+#[tokio::main]
+async fn main() {
+    // do not leak `RotatorSelect`
+    let _ = tokio::join!(async {
+        fn foo(_: impl RotatorSelect) {}
+    });
+
+    // do not leak `std::task::Poll::Pending`
+    let _ = tokio::join!(async { Pending });
+
+    // do not leak `std::task::Poll::Ready`
+    let _ = tokio::join!(async { Ready(0) });
+
+    // do not leak `std::future::Future`
+    let _ = tokio::join!(async {
+        struct MyFuture;
+
+        impl Future for MyFuture {
+            type Output = ();
+
+            fn poll(
+                self: std::pin::Pin<&mut Self>,
+                _cx: &mut std::task::Context<'_>,
+            ) -> std::task::Poll<Self::Output> {
+                todo!()
+            }
+        }
+    });
+
+    // do not leak `std::pin::Pin`
+    let _ = tokio::join!(async {
+        let mut x = 5;
+        let _ = Pin::new(&mut x);
+    });
+
+    // do not leak `std::future::poll_fn`
+    let _ = tokio::join!(async {
+        let _ = poll_fn(|_cx| todo!());
+    });
+}

tests-build/tests/fail/macros_join.stderr

@@ -0,0 +1,60 @@
+error[E0405]: cannot find trait `RotatorSelect` in this scope
+ --> tests/fail/macros_join.rs:7:24
+  |
+7 |         fn foo(_: impl RotatorSelect) {}
+  |                        ^^^^^^^^^^^^^ not found in this scope
+
+error[E0425]: cannot find value `Pending` in this scope
+  --> tests/fail/macros_join.rs:11:34
+   |
+11 |     let _ = tokio::join!(async { Pending });
+   |                                  ^^^^^^^ not found in this scope
+   |
+help: consider importing this unit variant
+   |
+ 1 + use std::task::Poll::Pending;
+   |
+
+error[E0425]: cannot find function, tuple struct or tuple variant `Ready` in this scope
+  --> tests/fail/macros_join.rs:14:34
+   |
+14 |     let _ = tokio::join!(async { Ready(0) });
+   |                                  ^^^^^ not found in this scope
+   |
+help: consider importing this tuple variant
+   |
+ 1 + use std::task::Poll::Ready;
+   |
+
+error[E0405]: cannot find trait `Future` in this scope
+  --> tests/fail/macros_join.rs:20:14
+   |
+20 |         impl Future for MyFuture {
+   |              ^^^^^^ not found in this scope
+   |
+help: consider importing this trait
+   |
+ 1 + use std::future::Future;
+   |
+
+error[E0433]: cannot find type `Pin` in this scope
+  --> tests/fail/macros_join.rs:35:17
+   |
+35 |         let _ = Pin::new(&mut x);
+   |                 ^^^ use of undeclared type `Pin`
+   |
+help: consider importing this struct
+   |
+ 1 + use std::pin::Pin;
+   |
+
+error[E0425]: cannot find function `poll_fn` in this scope
+  --> tests/fail/macros_join.rs:40:17
+   |
+40 |         let _ = poll_fn(|_cx| todo!());
+   |                 ^^^^^^^ not found in this scope
+   |
+help: consider importing this function
+   |
+ 1 + use std::future::poll_fn;
+   |

tests-build/tests/fail/macros_try_join.rs

@@ -0,0 +1,42 @@
+use tests_build::tokio;
+
+#[tokio::main]
+async fn main() {
+    // do not leak `RotatorSelect`
+    let _ = tokio::try_join!(async {
+        fn foo(_: impl RotatorSelect) {}
+    });
+
+    // do not leak `std::task::Poll::Pending`
+    let _ = tokio::try_join!(async { Pending });
+
+    // do not leak `std::task::Poll::Ready`
+    let _ = tokio::try_join!(async { Ready(0) });
+
+    // do not leak `std::future::Future`
+    let _ = tokio::try_join!(async {
+        struct MyFuture;
+
+        impl Future for MyFuture {
+            type Output = ();
+
+            fn poll(
+                self: std::pin::Pin<&mut Self>,
+                _cx: &mut std::task::Context<'_>,
+            ) -> std::task::Poll<Self::Output> {
+                todo!()
+            }
+        }
+    });
+
+    // do not leak `std::pin::Pin`
+    let _ = tokio::try_join!(async {
+        let mut x = 5;
+        let _ = Pin::new(&mut x);
+    });
+
+    // do not leak `std::future::poll_fn`
+    let _ = tokio::try_join!(async {
+        let _ = poll_fn(|_cx| todo!());
+    });
+}

tests-build/tests/fail/macros_try_join.stderr

@@ -0,0 +1,60 @@
+error[E0405]: cannot find trait `RotatorSelect` in this scope
+ --> tests/fail/macros_try_join.rs:7:24
+  |
+7 |         fn foo(_: impl RotatorSelect) {}
+  |                        ^^^^^^^^^^^^^ not found in this scope
+
+error[E0425]: cannot find value `Pending` in this scope
+  --> tests/fail/macros_try_join.rs:11:38
+   |
+11 |     let _ = tokio::try_join!(async { Pending });
+   |                                      ^^^^^^^ not found in this scope
+   |
+help: consider importing this unit variant
+   |
+ 1 + use std::task::Poll::Pending;
+   |
+
+error[E0425]: cannot find function, tuple struct or tuple variant `Ready` in this scope
+  --> tests/fail/macros_try_join.rs:14:38
+   |
+14 |     let _ = tokio::try_join!(async { Ready(0) });
+   |                                      ^^^^^ not found in this scope
+   |
+help: consider importing this tuple variant
+   |
+ 1 + use std::task::Poll::Ready;
+   |
+
+error[E0405]: cannot find trait `Future` in this scope
+  --> tests/fail/macros_try_join.rs:20:14
+   |
+20 |         impl Future for MyFuture {
+   |              ^^^^^^ not found in this scope
+   |
+help: consider importing this trait
+   |
+ 1 + use std::future::Future;
+   |
+
+error[E0433]: cannot find type `Pin` in this scope
+  --> tests/fail/macros_try_join.rs:35:17
+   |
+35 |         let _ = Pin::new(&mut x);
+   |                 ^^^ use of undeclared type `Pin`
+   |
+help: consider importing this struct
+   |
+ 1 + use std::pin::Pin;
+   |
+
+error[E0425]: cannot find function `poll_fn` in this scope
+  --> tests/fail/macros_try_join.rs:40:17
+   |
+40 |         let _ = poll_fn(|_cx| todo!());
+   |                 ^^^^^^^ not found in this scope
+   |
+help: consider importing this function
+   |
+ 1 + use std::future::poll_fn;
+   |

tests-build/tests/fail/macros_type_mismatch.stderr

@@ -1,3 +1,14 @@
+error[E0271]: expected `{async block@$DIR/tests/fail/macros_type_mismatch.rs:3:1: 3:15}` to be a future that resolves to `()`, but it resolves to `Result<(), _>`
+ --> tests/fail/macros_type_mismatch.rs:3:1
+  |
+3 | #[tokio::main]
+  | ^^^^^^^^^^^^^^ expected `()`, found `Result<(), _>`
+  |
+  = note: expected unit type `()`
+                  found enum `Result<(), _>`
+  = note: required for the cast from `&{async block@$DIR/tests/fail/macros_type_mismatch.rs:3:1: 3:15}` to `&dyn Future<Output = ()>`
+  = note: this error originates in the attribute macro `tokio::main` (in Nightly builds, run with -Z macro-backtrace for more info)
+
 error[E0308]: mismatched types
  --> tests/fail/macros_type_mismatch.rs:5:5
   |
@@ -15,6 +26,17 @@ help: consider using `Result::expect` to unwrap the `Result<(), _>` value, panic
 5 |     Ok(()).expect("REASON")
   |           +++++++++++++++++
 
+error[E0271]: expected `{async block@$DIR/tests/fail/macros_type_mismatch.rs:8:1: 8:15}` to be a future that resolves to `()`, but it resolves to `Result<(), _>`
+ --> tests/fail/macros_type_mismatch.rs:8:1
+  |
+8 | #[tokio::main]
+  | ^^^^^^^^^^^^^^ expected `()`, found `Result<(), _>`
+  |
+  = note: expected unit type `()`
+                  found enum `Result<(), _>`
+  = note: required for the cast from `&{async block@$DIR/tests/fail/macros_type_mismatch.rs:8:1: 8:15}` to `&dyn Future<Output = ()>`
+  = note: this error originates in the attribute macro `tokio::main` (in Nightly builds, run with -Z macro-backtrace for more info)
+
 error[E0308]: mismatched types
   --> tests/fail/macros_type_mismatch.rs:10:5
    |
@@ -25,13 +47,24 @@ error[E0308]: mismatched types
                    found enum `Result<(), _>`
 help: a return type might be missing here
    |
-9  | async fn missing_return_type() -> _ {
+ 9 | async fn missing_return_type() -> _ {
    |                                ++++
 help: consider using `Result::expect` to unwrap the `Result<(), _>` value, panicking if the value is a `Result::Err`
    |
 10 |     return Ok(());.expect("REASON")
    |                   +++++++++++++++++
 
+error[E0271]: expected `{async block@$DIR/tests/fail/macros_type_mismatch.rs:13:1: 13:15}` to be a future that resolves to `Result<(), ()>`, but it resolves to `()`
+  --> tests/fail/macros_type_mismatch.rs:13:1
+   |
+13 | #[tokio::main]
+   | ^^^^^^^^^^^^^^ expected `Result<(), ()>`, found `()`
+   |
+   = note:   expected enum `Result<(), ()>`
+           found unit type `()`
+   = note: required for the cast from `&{async block@$DIR/tests/fail/macros_type_mismatch.rs:13:1: 13:15}` to `&dyn Future<Output = Result<(), ()>>`
+   = note: this error originates in the attribute macro `tokio::main` (in Nightly builds, run with -Z macro-backtrace for more info)
+
 error[E0308]: mismatched types
   --> tests/fail/macros_type_mismatch.rs:23:5
    |
@@ -57,8 +90,17 @@ error[E0277]: the `?` operator can only be used in an async block that returns `
 39 | async fn question_mark_operator_with_invalid_option() -> Option<()> {
 40 |     None?;
    |         ^ cannot use the `?` operator in an async block that returns `()`
+
+error[E0271]: expected `{async block@$DIR/tests/fail/macros_type_mismatch.rs:38:1: 38:15}` to be a future that resolves to `Option<()>`, but it resolves to `()`
+  --> tests/fail/macros_type_mismatch.rs:38:1
    |
-   = help: the trait `FromResidual<Option<Infallible>>` is not implemented for `()`
+38 | #[tokio::main]
+   | ^^^^^^^^^^^^^^ expected `Option<()>`, found `()`
+   |
+   = note:   expected enum `Option<()>`
+           found unit type `()`
+   = note: required for the cast from `&{async block@$DIR/tests/fail/macros_type_mismatch.rs:38:1: 38:15}` to `&dyn Future<Output = Option<()>>`
+   = note: this error originates in the attribute macro `tokio::main` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0308]: mismatched types
   --> tests/fail/macros_type_mismatch.rs:40:5
@@ -87,8 +129,17 @@ error[E0277]: the `?` operator can only be used in an async block that returns `
 56 | async fn question_mark_operator_with_invalid_result() -> Result<(), ()> {
 57 |     Ok(())?;
    |           ^ cannot use the `?` operator in an async block that returns `()`
+
+error[E0271]: expected `{async block@$DIR/tests/fail/macros_type_mismatch.rs:55:1: 55:15}` to be a future that resolves to `Result<(), ()>`, but it resolves to `()`
+  --> tests/fail/macros_type_mismatch.rs:55:1
    |
-   = help: the trait `FromResidual<Result<Infallible, _>>` is not implemented for `()`
+55 | #[tokio::main]
+   | ^^^^^^^^^^^^^^ expected `Result<(), ()>`, found `()`
+   |
+   = note:   expected enum `Result<(), ()>`
+           found unit type `()`
+   = note: required for the cast from `&{async block@$DIR/tests/fail/macros_type_mismatch.rs:55:1: 55:15}` to `&dyn Future<Output = Result<(), ()>>`
+   = note: this error originates in the attribute macro `tokio::main` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0308]: mismatched types
   --> tests/fail/macros_type_mismatch.rs:57:5
@@ -106,6 +157,15 @@ help: try adding an expression at the end of the block
 58 +     Ok(())
    |
 
+error[E0271]: expected `{async block@$DIR/tests/fail/macros_type_mismatch.rs:63:1: 63:15}` to be a future that resolves to `()`, but it resolves to `{integer}`
+  --> tests/fail/macros_type_mismatch.rs:63:1
+   |
+63 | #[tokio::main]
+   | ^^^^^^^^^^^^^^ expected `()`, found integer
+   |
+   = note: required for the cast from `&{async block@$DIR/tests/fail/macros_type_mismatch.rs:63:1: 63:15}` to `&dyn Future<Output = ()>`
+   = note: this error originates in the attribute macro `tokio::main` (in Nightly builds, run with -Z macro-backtrace for more info)
+
 error[E0308]: mismatched types
   --> tests/fail/macros_type_mismatch.rs:66:5
    |

tests-build/tests/macros.rs

@@ -12,12 +12,24 @@ fn compile_fail_full() {
     #[cfg(feature = "full")]
     t.pass("tests/pass/macros_main_loop.rs");
 
+    #[cfg(feature = "full")]
+    t.pass("tests/pass/impl_trait.rs");
+
+    #[cfg(feature = "full")]
+    t.pass("tests/pass/use_builder_outer.rs");
+
     #[cfg(feature = "full")]
     t.compile_fail("tests/fail/macros_invalid_input.rs");
 
     #[cfg(feature = "full")]
     t.compile_fail("tests/fail/macros_dead_code.rs");
 
+    #[cfg(feature = "full")]
+    t.compile_fail("tests/fail/macros_join.rs");
+
+    #[cfg(feature = "full")]
+    t.compile_fail("tests/fail/macros_try_join.rs");
+
     #[cfg(feature = "full")]
     t.compile_fail("tests/fail/macros_type_mismatch.rs");
 

tests-build/tests/pass/impl_trait.rs

@@ -0,0 +1,23 @@
+use tests_build::tokio;
+
+#[tokio::main]
+async fn never() -> ! {
+    loop {}
+}
+
+#[tokio::main]
+async fn impl_trait() -> impl Iterator<Item = impl core::fmt::Debug> {
+    [()].into_iter()
+}
+
+#[tokio::main]
+async fn impl_trait2() -> Result<(), impl core::fmt::Debug> {
+    Err(())
+}
+
+fn main() {
+    if impl_trait().count() == 10 {
+        never();
+    }
+    let _ = impl_trait2();
+}

tests-build/tests/pass/use_builder_outer.rs

@@ -0,0 +1,9 @@
+#![deny(unused_qualifications)]
+
+use tests_build::tokio;
+pub use tokio::runtime;
+
+#[tokio::main]
+async fn main() {
+    if true {}
+}

tests-integration/tests/macros_main.rs

@@ -16,6 +16,13 @@ async fn spawning() -> usize {
     join.await.unwrap()
 }
 
+#[cfg(tokio_unstable)]
+#[tokio::main(flavor = "local")]
+async fn local_main() -> usize {
+    let join = tokio::task::spawn_local(async { 1 });
+    join.await.unwrap()
+}
+
 #[test]
 fn main_with_spawn() {
     assert_eq!(1, spawning());
@@ -24,5 +31,8 @@ fn main_with_spawn() {
 #[test]
 fn shell() {
     assert_eq!(1, basic_main());
-    assert_eq!(bool::default(), generic_fun::<bool>())
+    assert_eq!(bool::default(), generic_fun::<bool>());
+
+    #[cfg(tokio_unstable)]
+    assert_eq!(1, local_main());
 }

tests-integration/tests/process_stdio.rs

@@ -25,7 +25,7 @@ async fn feed_cat(mut cat: Child, n: usize) -> io::Result<ExitStatus> {
     // Produce n lines on the child's stdout.
     let write = async {
         for i in 0..n {
-            let bytes = format!("line {}\n", i).into_bytes();
+            let bytes = format!("line {i}\n").into_bytes();
             stdin.write_all(&bytes).await.unwrap();
         }
 
@@ -52,7 +52,7 @@ async fn feed_cat(mut cat: Child, n: usize) -> io::Result<ExitStatus> {
                 (false, 0) => panic!("broken pipe"),
                 (true, n) if n != 0 => panic!("extraneous data"),
                 _ => {
-                    let expected = format!("line {}", num_lines);
+                    let expected = format!("line {num_lines}");
                     assert_eq!(expected, data);
                 }
             };

tokio-macros/CHANGELOG.md

@@ -1,3 +1,32 @@
+# 2.7.0 (April 3rd, 2026)
+
+- macros: stabilize `LocalRuntime` ([#7557])
+- macros: add runtime name ([#7924])
+
+[#7557]: https://github.com/tokio-rs/tokio/pull/7557
+[#7924]: https://github.com/tokio-rs/tokio/pull/7924
+
+# 2.6.1 (Mar 2nd, 2026)
+
+- macros: improve error message for return type mismatch in #[tokio::main] ([#7856])
+- macros: use call_site hygiene to avoid unused qualification ([#7866])
+
+[#7856]: https://github.com/tokio-rs/tokio/pull/7856
+[#7866]: https://github.com/tokio-rs/tokio/pull/7866
+
+# 2.6.0 (Oct 14th, 2025)
+
+The MSRV is raised to 1.71.
+
+- msrv: increase MSRV to 1.71 ([#7658])
+- macros: add `local` runtime flavor ([#7375], [#7597])
+- macros: suppress `clippy::unwrap_in_result` in `#[tokio::main]` ([#7651])
+
+[#7375]: https://github.com/tokio-rs/tokio/pull/7375
+[#7597]: https://github.com/tokio-rs/tokio/pull/7597
+[#7651]: https://github.com/tokio-rs/tokio/pull/7651
+[#7658]: https://github.com/tokio-rs/tokio/pull/7658
+
 # 2.5.0 (Jan 8th, 2025)
 
 - macros: suppress `clippy::needless_return` in `#[tokio::main]` ([#6874])

tokio-macros/Cargo.toml

@@ -1,12 +1,12 @@
 [package]
 name = "tokio-macros"
 # When releasing to crates.io:
-# - Remove path dependencies
+# - Remove path dependencies (if any)
 # - Update CHANGELOG.md.
-# - Create "tokio-macros-1.x.y" git tag.
-version = "2.5.0"
+# - Create "tokio-macros-x.y.z" git tag.
+version = "2.7.0"
 edition = "2021"
-rust-version = "1.70"
+rust-version = "1.71"
 authors = ["Tokio Contributors <[email protected]>"]
 license = "MIT"
 repository = "https://github.com/tokio-rs/tokio"
@@ -27,7 +27,7 @@ quote = "1"
 syn = { version = "2.0", features = ["full"] }
 
 [dev-dependencies]
-tokio = { version = "1.0.0", path = "../tokio", features = ["full"] }
+tokio = { version = "1.0.0", features = ["full", "test-util"] }
 
 [package.metadata.docs.rs]
 all-features = true

tokio-macros/src/entry.rs

@@ -10,6 +10,7 @@ type AttributeArgs = syn::punctuated::Punctuated<syn::Meta, syn::Token![,]>;
 enum RuntimeFlavor {
     CurrentThread,
     Threaded,
+    Local,
 }
 
 impl RuntimeFlavor {
@@ -17,10 +18,11 @@ impl RuntimeFlavor {
         match s {
             "current_thread" => Ok(RuntimeFlavor::CurrentThread),
             "multi_thread" => Ok(RuntimeFlavor::Threaded),
+            "local" => Ok(RuntimeFlavor::Local),
             "single_thread" => Err("The single threaded runtime flavor is called `current_thread`.".to_string()),
             "basic_scheduler" => Err("The `basic_scheduler` runtime flavor has been renamed to `current_thread`.".to_string()),
             "threaded_scheduler" => Err("The `threaded_scheduler` runtime flavor has been renamed to `multi_thread`.".to_string()),
-            _ => Err(format!("No such runtime flavor `{s}`. The runtime flavors are `current_thread` and `multi_thread`.")),
+            _ => Err(format!("No such runtime flavor `{s}`. The runtime flavors are `current_thread`, `local`, and `multi_thread`.")),
         }
     }
 }
@@ -51,6 +53,7 @@ impl UnhandledPanic {
 }
 
 struct FinalConfig {
+    name: Option<String>,
     flavor: RuntimeFlavor,
     worker_threads: Option<usize>,
     start_paused: Option<bool>,
@@ -60,6 +63,7 @@ struct FinalConfig {
 
 /// Config used in case of the attribute not being able to build a valid config
 const DEFAULT_ERROR_CONFIG: FinalConfig = FinalConfig {
+    name: None,
     flavor: RuntimeFlavor::CurrentThread,
     worker_threads: None,
     start_paused: None,
@@ -68,6 +72,7 @@ const DEFAULT_ERROR_CONFIG: FinalConfig = FinalConfig {
 };
 
 struct Configuration {
+    name: Option<String>,
     rt_multi_thread_available: bool,
     default_flavor: RuntimeFlavor,
     flavor: Option<RuntimeFlavor>,
@@ -81,6 +86,7 @@ struct Configuration {
 impl Configuration {
     fn new(is_test: bool, rt_multi_thread: bool) -> Self {
         Configuration {
+            name: None,
             rt_multi_thread_available: rt_multi_thread,
             default_flavor: match is_test {
                 true => RuntimeFlavor::CurrentThread,
@@ -95,6 +101,16 @@ impl Configuration {
         }
     }
 
+    fn set_name(&mut self, name: syn::Lit, span: Span) -> Result<(), syn::Error> {
+        if self.name.is_some() {
+            return Err(syn::Error::new(span, "`name` set multiple times."));
+        }
+
+        let runtime_name = parse_string(name, span, "name")?;
+        self.name = Some(runtime_name);
+        Ok(())
+    }
+
     fn set_flavor(&mut self, runtime: syn::Lit, span: Span) -> Result<(), syn::Error> {
         if self.flavor.is_some() {
             return Err(syn::Error::new(span, "`flavor` set multiple times."));
@@ -177,15 +193,16 @@ impl Configuration {
         use RuntimeFlavor as F;
 
         let flavor = self.flavor.unwrap_or(self.default_flavor);
+
         let worker_threads = match (flavor, self.worker_threads) {
-            (F::CurrentThread, Some((_, worker_threads_span))) => {
+            (F::CurrentThread | F::Local, Some((_, worker_threads_span))) => {
                 let msg = format!(
                     "The `worker_threads` option requires the `multi_thread` runtime flavor. Use `#[{}(flavor = \"multi_thread\")]`",
                     self.macro_name(),
                 );
                 return Err(syn::Error::new(worker_threads_span, msg));
             }
-            (F::CurrentThread, None) => None,
+            (F::CurrentThread | F::Local, None) => None,
             (F::Threaded, worker_threads) if self.rt_multi_thread_available => {
                 worker_threads.map(|(val, _span)| val)
             }
@@ -207,7 +224,7 @@ impl Configuration {
                 );
                 return Err(syn::Error::new(start_paused_span, msg));
             }
-            (F::CurrentThread, Some((start_paused, _))) => Some(start_paused),
+            (F::CurrentThread | F::Local, Some((start_paused, _))) => Some(start_paused),
             (_, None) => None,
         };
 
@@ -219,11 +236,12 @@ impl Configuration {
                 );
                 return Err(syn::Error::new(unhandled_panic_span, msg));
             }
-            (F::CurrentThread, Some((unhandled_panic, _))) => Some(unhandled_panic),
+            (F::CurrentThread | F::Local, Some((unhandled_panic, _))) => Some(unhandled_panic),
             (_, None) => None,
         };
 
         Ok(FinalConfig {
+            name: self.name.clone(),
             crate_name: self.crate_name.clone(),
             flavor,
             worker_threads,
@@ -290,6 +308,35 @@ fn parse_bool(bool: syn::Lit, span: Span, field: &str) -> Result<bool, syn::Erro
     }
 }
 
+fn contains_impl_trait(ty: &syn::Type) -> bool {
+    match ty {
+        syn::Type::ImplTrait(_) => true,
+        syn::Type::Array(t) => contains_impl_trait(&t.elem),
+        syn::Type::Ptr(t) => contains_impl_trait(&t.elem),
+        syn::Type::Reference(t) => contains_impl_trait(&t.elem),
+        syn::Type::Slice(t) => contains_impl_trait(&t.elem),
+        syn::Type::Tuple(t) => t.elems.iter().any(contains_impl_trait),
+        syn::Type::Paren(t) => contains_impl_trait(&t.elem),
+        syn::Type::Group(t) => contains_impl_trait(&t.elem),
+        syn::Type::Path(t) => match t.path.segments.last() {
+            Some(segment) => match &segment.arguments {
+                syn::PathArguments::AngleBracketed(args) => args.args.iter().any(|arg| match arg {
+                    syn::GenericArgument::Type(t) => contains_impl_trait(t),
+                    syn::GenericArgument::AssocType(t) => contains_impl_trait(&t.ty),
+                    _ => false,
+                }),
+                syn::PathArguments::Parenthesized(args) => {
+                    args.inputs.iter().any(contains_impl_trait)
+                        || matches!(&args.output, syn::ReturnType::Type(_, t) if contains_impl_trait(t))
+                }
+                syn::PathArguments::None => false,
+            },
+            None => false,
+        },
+        _ => false,
+    }
+}
+
 fn build_config(
     input: &ItemFn,
     args: AttributeArgs,
@@ -340,9 +387,12 @@ fn build_config(
                         config
                             .set_unhandled_panic(lit.clone(), syn::spanned::Spanned::span(lit))?;
                     }
+                    "name" => {
+                        config.set_name(lit.clone(), syn::spanned::Spanned::span(lit))?;
+                    }
                     name => {
                         let msg = format!(
-                            "Unknown attribute {name} is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`, `unhandled_panic`",
+                            "Unknown attribute {name} is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`, `unhandled_panic`, `name`.",
                         );
                         return Err(syn::Error::new_spanned(namevalue, msg));
                     }
@@ -365,11 +415,12 @@ fn build_config(
                             "Set the runtime flavor with #[{macro_name}(flavor = \"current_thread\")]."
                         )
                     }
-                    "flavor" | "worker_threads" | "start_paused" | "crate" | "unhandled_panic" => {
+                    "flavor" | "worker_threads" | "start_paused" | "crate" | "unhandled_panic"
+                    | "name" => {
                         format!("The `{name}` attribute requires an argument.")
                     }
                     name => {
-                        format!("Unknown attribute {name} is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`, `unhandled_panic`.")
+                        format!("Unknown attribute {name} is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`, `unhandled_panic`, `name`.")
                     }
                 };
                 return Err(syn::Error::new_spanned(path, msg));
@@ -405,16 +456,32 @@ fn parse_knobs(mut input: ItemFn, is_test: bool, config: FinalConfig) -> TokenSt
     let crate_path = config
         .crate_name
         .map(ToTokens::into_token_stream)
-        .unwrap_or_else(|| Ident::new("tokio", last_stmt_start_span).into_token_stream());
+        .unwrap_or_else(|| {
+            Ident::new("tokio", Span::call_site().located_at(last_stmt_start_span))
+                .into_token_stream()
+        });
+
+    let use_builder = quote_spanned! {Span::call_site().located_at(last_stmt_start_span)=>
+        use #crate_path::runtime::Builder;
+    };
 
     let mut rt = match config.flavor {
-        RuntimeFlavor::CurrentThread => quote_spanned! {last_stmt_start_span=>
-            #crate_path::runtime::Builder::new_current_thread()
-        },
+        RuntimeFlavor::CurrentThread | RuntimeFlavor::Local => {
+            quote_spanned! {last_stmt_start_span=>
+                Builder::new_current_thread()
+            }
+        }
         RuntimeFlavor::Threaded => quote_spanned! {last_stmt_start_span=>
-            #crate_path::runtime::Builder::new_multi_thread()
+            Builder::new_multi_thread()
         },
     };
+
+    let build = if let RuntimeFlavor::Local = config.flavor {
+        quote_spanned! {last_stmt_start_span=> build_local(Default::default())}
+    } else {
+        quote_spanned! {last_stmt_start_span=> build()}
+    };
+
     if let Some(v) = config.worker_threads {
         rt = quote_spanned! {last_stmt_start_span=> #rt.worker_threads(#v) };
     }
@@ -425,6 +492,9 @@ fn parse_knobs(mut input: ItemFn, is_test: bool, config: FinalConfig) -> TokenSt
         let unhandled_panic = v.into_tokens(&crate_path);
         rt = quote_spanned! {last_stmt_start_span=> #rt.unhandled_panic(#unhandled_panic) };
     }
+    if let Some(v) = config.name {
+        rt = quote_spanned! {last_stmt_start_span=> #rt.name(#v) };
+    }
 
     let generated_attrs = if is_test {
         quote! {
@@ -437,14 +507,18 @@ fn parse_knobs(mut input: ItemFn, is_test: bool, config: FinalConfig) -> TokenSt
     let body_ident = quote! { body };
     // This explicit `return` is intentional. See tokio-rs/tokio#4636
     let last_block = quote_spanned! {last_stmt_end_span=>
-        #[allow(clippy::expect_used, clippy::diverging_sub_expression, clippy::needless_return)]
+
+        #[allow(clippy::expect_used, clippy::diverging_sub_expression, clippy::needless_return, clippy::unwrap_in_result)]
         {
+            #use_builder
+
             return #rt
                 .enable_all()
-                .build()
+                .#build
                 .expect("Failed building the Runtime")
                 .block_on(#body_ident);
         }
+
     };
 
     let body = input.body();
@@ -458,22 +532,42 @@ fn parse_knobs(mut input: ItemFn, is_test: bool, config: FinalConfig) -> TokenSt
     //
     // We don't do this for the main function as it should only be used once so
     // there will be no benefit.
+    let output_type = match &input.sig.output {
+        // For functions with no return value syn doesn't print anything,
+        // but that doesn't work as `Output` for our boxed `Future`, so
+        // default to `()` (the same type as the function output).
+        syn::ReturnType::Default => quote! { () },
+        syn::ReturnType::Type(_, ret_type) => quote! { #ret_type },
+    };
+
     let body = if is_test {
-        let output_type = match &input.sig.output {
-            // For functions with no return value syn doesn't print anything,
-            // but that doesn't work as `Output` for our boxed `Future`, so
-            // default to `()` (the same type as the function output).
-            syn::ReturnType::Default => quote! { () },
-            syn::ReturnType::Type(_, ret_type) => quote! { #ret_type },
-        };
         quote! {
             let body = async #body;
             #crate_path::pin!(body);
             let body: ::core::pin::Pin<&mut dyn ::core::future::Future<Output = #output_type>> = body;
         }
     } else {
+        // force typecheck without runtime overhead
+        let check_block = match &input.sig.output {
+            syn::ReturnType::Type(_, t)
+                if matches!(**t, syn::Type::Never(_)) || contains_impl_trait(t) =>
+            {
+                quote! {}
+            }
+            _ => quote! {
+                if false {
+                    let _: &dyn ::core::future::Future<Output = #output_type> = &body;
+                }
+            },
+        };
+
         quote! {
             let body = async #body;
+            // Compile-time assertion that the future's output matches the return type.
+            let body = {
+                #check_block
+                body
+            };
         }
     };
 

tokio-macros/src/lib.rs

@@ -12,11 +12,6 @@
 
 //! Macros for use with Tokio
 
-// This `extern` is required for older `rustc` versions but newer `rustc`
-// versions warn about the unused `extern crate`.
-#[allow(unused_extern_crates)]
-extern crate proc_macro;
-
 mod entry;
 mod select;
 
@@ -46,7 +41,12 @@ use proc_macro::TokenStream;
 /// Awaiting on other futures from the function provided here will not
 /// perform as fast as those spawned as workers.
 ///
-/// # Multi-threaded runtime
+/// # Runtime flavors
+///
+/// The macro can be configured with a `flavor` parameter to select
+/// different runtime configurations.
+///
+/// ## Multi-threaded
 ///
 /// To use the multi-threaded runtime, the macro can be configured using
 ///
@@ -61,23 +61,56 @@ use proc_macro::TokenStream;
 /// Note: The multi-threaded runtime requires the `rt-multi-thread` feature
 /// flag.
 ///
-/// # Current thread runtime
+/// ## Current-thread
 ///
 /// To use the single-threaded runtime known as the `current_thread` runtime,
 /// the macro can be configured using
 ///
-/// ```
+/// ```rust
 /// #[tokio::main(flavor = "current_thread")]
 /// # async fn main() {}
 /// ```
 ///
-/// ## Function arguments:
+/// ## Local
 ///
-/// Arguments are allowed for any functions aside from `main` which is special
+/// To use the [local runtime], the macro can be configured using
 ///
-/// ## Usage
+/// ```rust
+/// #[tokio::main(flavor = "local")]
+/// # async fn main() {}
+/// ```
 ///
-/// ### Using the multi-thread runtime
+/// # Function arguments
+///
+/// Arguments are allowed for any functions, aside from `main` which is special.
+///
+/// # Usage
+///
+/// ## Set the name of the runtime
+///
+/// ```rust
+/// #[tokio::main(name = "my-runtime")]
+/// async fn main() {
+///     println!("Hello world");
+/// }
+/// ```
+///
+/// Equivalent code not using `#[tokio::main]`
+///
+/// ```rust
+/// fn main() {
+///     tokio::runtime::Builder::new_multi_thread()
+///         .enable_all()
+///         .name("my-runtime")
+///         .build()
+///         .unwrap()
+///         .block_on(async {
+///             println!("Hello world");
+///         })
+/// }
+/// ```
+///
+/// ## Using the multi-threaded runtime
 ///
 /// ```rust
 /// #[tokio::main]
@@ -100,7 +133,7 @@ use proc_macro::TokenStream;
 /// }
 /// ```
 ///
-/// ### Using current thread runtime
+/// ## Using the current-thread runtime
 ///
 /// The basic scheduler is single-threaded.
 ///
@@ -125,7 +158,34 @@ use proc_macro::TokenStream;
 /// }
 /// ```
 ///
-/// ### Set number of worker threads
+/// ## Using the local runtime
+///
+/// The [local runtime] is similar to the current-thread runtime but
+/// supports [`task::spawn_local`](../tokio/task/fn.spawn_local.html).
+///
+/// ```rust
+/// #[tokio::main(flavor = "local")]
+/// async fn main() {
+///     println!("Hello world");
+/// }
+/// ```
+///
+/// Equivalent code not using `#[tokio::main]`
+///
+/// ```rust
+/// fn main() {
+///     tokio::runtime::Builder::new_current_thread()
+///         .enable_all()
+///         .build_local(tokio::runtime::LocalOptions::default())
+///         .unwrap()
+///         .block_on(async {
+///             println!("Hello world");
+///         })
+/// }
+/// ```
+///
+///
+/// ## Set number of worker threads
 ///
 /// ```rust
 /// #[tokio::main(worker_threads = 2)]
@@ -149,7 +209,7 @@ use proc_macro::TokenStream;
 /// }
 /// ```
 ///
-/// ### Configure the runtime to start with time paused
+/// ## Configure the runtime to start with time paused
 ///
 /// ```rust
 /// #[tokio::main(flavor = "current_thread", start_paused = true)]
@@ -175,7 +235,7 @@ use proc_macro::TokenStream;
 ///
 /// Note that `start_paused` requires the `test-util` feature to be enabled.
 ///
-/// ### Rename package
+/// ## Rename package
 ///
 /// ```rust
 /// use tokio as tokio1;
@@ -202,7 +262,7 @@ use proc_macro::TokenStream;
 /// }
 /// ```
 ///
-/// ### Configure unhandled panic behavior
+/// ## Configure unhandled panic behavior
 ///
 /// Available options are `shutdown_runtime` and `ignore`. For more details, see
 /// [`Builder::unhandled_panic`].
@@ -228,7 +288,7 @@ use proc_macro::TokenStream;
 /// fn main() {
 ///     tokio::runtime::Builder::new_current_thread()
 ///         .enable_all()
-///         .unhandled_panic(UnhandledPanic::ShutdownRuntime)
+///         .unhandled_panic(tokio::runtime::UnhandledPanic::ShutdownRuntime)
 ///         .build()
 ///         .unwrap()
 ///         .block_on(async {
@@ -247,6 +307,7 @@ use proc_macro::TokenStream;
 ///
 /// [`Builder::unhandled_panic`]: ../tokio/runtime/struct.Builder.html#method.unhandled_panic
 /// [unstable]: ../tokio/index.html#unstable-features
+/// [local runtime]: ../tokio/runtime/struct.LocalRuntime.html
 #[proc_macro_attribute]
 pub fn main(args: TokenStream, item: TokenStream) -> TokenStream {
     entry::main(args.into(), item.into(), true).into()
@@ -358,6 +419,31 @@ pub fn main_rt(args: TokenStream, item: TokenStream) -> TokenStream {
 ///
 /// ## Usage
 ///
+/// ### Set the name of the runtime
+///
+/// ```no_run
+/// #[tokio::test(name = "my-test-runtime")]
+/// async fn my_test() {
+///     assert!(true);
+/// }
+/// ```
+///
+/// Equivalent code not using `#[tokio::test]`
+///
+/// ```no_run
+/// #[test]
+/// fn my_test() {
+///     tokio::runtime::Builder::new_current_thread()
+///         .enable_all()
+///         .name("my-test-runtime")
+///         .build()
+///         .unwrap()
+///         .block_on(async {
+///             assert!(true);
+///         })
+/// }
+/// ```
+///
 /// ### Using the multi-thread runtime
 ///
 /// ```no_run
@@ -484,7 +570,7 @@ pub fn main_rt(args: TokenStream, item: TokenStream) -> TokenStream {
 ///         panic!("This panic will shutdown the runtime.");
 ///     }).await;
 /// }
-/// # #[cfg(not(tokio_unstable))]
+///
 /// # fn main() { }
 /// ```
 ///
@@ -505,7 +591,7 @@ pub fn main_rt(args: TokenStream, item: TokenStream) -> TokenStream {
 ///             }).await;
 ///         })
 /// }
-/// # #[cfg(not(tokio_unstable))]
+///
 /// # fn main() { }
 /// ```
 ///

tokio-stream/CHANGELOG.md

@@ -1,3 +1,25 @@
+# 0.1.18 (January 4th, 2026)
+
+### Added
+
+- stream: add `ChunksTimeout::into_remainder` ([#7715])
+- stream: add examples to wrapper types ([#7024])
+- sync: implement `Stream::size_hint` for `ReceiverStream` and `UnboundedReceiverStream` ([#7492])
+
+### Fixed
+
+- stream: work around the rustc bug in `StreamExt::collect` ([#7754])
+
+### Documented
+
+- stream: improve the docs of `TcpListenerStream` ([#7578])
+
+[#7024]: https://github.com/tokio-rs/tokio/pull/7024
+[#7492]: https://github.com/tokio-rs/tokio/pull/7492
+[#7578]: https://github.com/tokio-rs/tokio/pull/7578
+[#7715]: https://github.com/tokio-rs/tokio/pull/7715
+[#7754]: https://github.com/tokio-rs/tokio/pull/7754
+
 # 0.1.17 (December 6th, 2024)
 
 - deps: fix dev-dependency on tokio-test ([#6931], [#7019])

tokio-stream/Cargo.toml

@@ -1,12 +1,12 @@
 [package]
 name = "tokio-stream"
 # When releasing to crates.io:
-# - Remove path dependencies
+# - Remove path dependencies (if any)
 # - Update CHANGELOG.md.
 # - Create "tokio-stream-0.1.x" git tag.
-version = "0.1.17"
+version = "0.1.18"
 edition = "2021"
-rust-version = "1.70"
+rust-version = "1.71"
 authors = ["Tokio Contributors <[email protected]>"]
 license = "MIT"
 repository = "https://github.com/tokio-rs/tokio"
@@ -38,14 +38,14 @@ signal = ["tokio/signal"]
 [dependencies]
 futures-core = { version = "0.3.0" }
 pin-project-lite = "0.2.11"
-tokio = { version = "1.15.0", path = "../tokio", features = ["sync"] }
-tokio-util = { version = "0.7.0", path = "../tokio-util", optional = true }
+tokio = { version = "1.38.0", features = ["sync"] }
+tokio-util = { version = "0.7.0", optional = true }
 
 [dev-dependencies]
-tokio = { version = "1.2.0", path = "../tokio", features = ["full", "test-util"] }
+tokio = { version = "1.38.0", features = ["full", "test-util"] }
 async-stream = "0.3"
 parking_lot = "0.12.0"
-tokio-test = { version = "0.4", path = "../tokio-test" }
+tokio-test = "0.4"
 futures = { version = "0.3", default-features = false }
 
 [package.metadata.docs.rs]

tokio-stream/src/empty.rs

@@ -26,12 +26,12 @@ unsafe impl<T> Sync for Empty<T> {}
 /// ```
 /// use tokio_stream::{self as stream, StreamExt};
 ///
-/// #[tokio::main]
-/// async fn main() {
-///     let mut none = stream::empty::<i32>();
+/// # #[tokio::main(flavor = "current_thread")]
+/// # async fn main() {
+/// let mut none = stream::empty::<i32>();
 ///
-///     assert_eq!(None, none.next().await);
-/// }
+/// assert_eq!(None, none.next().await);
+/// # }
 /// ```
 pub const fn empty<T>() -> Empty<T> {
     Empty(PhantomData)

tokio-stream/src/lib.rs

@@ -34,14 +34,14 @@
 //! ```rust
 //! use tokio_stream::{self as stream, StreamExt};
 //!
-//! #[tokio::main]
-//! async fn main() {
-//!     let mut stream = stream::iter(vec![0, 1, 2]);
+//! # #[tokio::main(flavor = "current_thread")]
+//! # async fn main() {
+//! let mut stream = stream::iter(vec![0, 1, 2]);
 //!
-//!     while let Some(value) = stream.next().await {
-//!         println!("Got {}", value);
-//!     }
+//! while let Some(value) = stream.next().await {
+//!     println!("Got {}", value);
 //! }
+//! # }
 //! ```
 //!
 //! # Returning a Stream from a function

tokio-stream/src/once.rs

@@ -22,16 +22,16 @@ impl<I> Unpin for Once<I> {}
 /// ```
 /// use tokio_stream::{self as stream, StreamExt};
 ///
-/// #[tokio::main]
-/// async fn main() {
-///     // one is the loneliest number
-///     let mut one = stream::once(1);
+/// # #[tokio::main(flavor = "current_thread")]
+/// # async fn main() {
+/// // one is the loneliest number
+/// let mut one = stream::once(1);
 ///
-///     assert_eq!(Some(1), one.next().await);
+/// assert_eq!(Some(1), one.next().await);
 ///
-///     // just one, that's all we get
-///     assert_eq!(None, one.next().await);
-/// }
+/// // just one, that's all we get
+/// assert_eq!(None, one.next().await);
+/// # }
 /// ```
 pub fn once<T>(value: T) -> Once<T> {
     Once {

tokio-stream/src/pending.rs

@@ -17,7 +17,7 @@ unsafe impl<T> Sync for Pending<T> {}
 ///
 /// The returned stream is never ready. Attempting to call
 /// [`next()`](crate::StreamExt::next) will never complete. Use
-/// [`stream::empty()`](super::empty()) to obtain a stream that is is
+/// [`stream::empty()`](super::empty()) to obtain a stream that is
 /// immediately empty but returns no values.
 ///
 /// # Examples

tokio-stream/src/stream_close.rs

@@ -17,20 +17,20 @@ pin_project! {
     /// ```
     /// use tokio_stream::{StreamExt, StreamMap, StreamNotifyClose};
     ///
-    /// #[tokio::main]
-    /// async fn main() {
-    ///     let mut map = StreamMap::new();
-    ///     let stream = StreamNotifyClose::new(tokio_stream::iter(vec![0, 1]));
-    ///     let stream2 = StreamNotifyClose::new(tokio_stream::iter(vec![0, 1]));
-    ///     map.insert(0, stream);
-    ///     map.insert(1, stream2);
-    ///     while let Some((key, val)) = map.next().await {
-    ///         match val {
-    ///             Some(val) => println!("got {val:?} from stream {key:?}"),
-    ///             None => println!("stream {key:?} closed"),
-    ///         }
+    /// # #[tokio::main(flavor = "current_thread")]
+    /// # async fn main() {
+    /// let mut map = StreamMap::new();
+    /// let stream = StreamNotifyClose::new(tokio_stream::iter(vec![0, 1]));
+    /// let stream2 = StreamNotifyClose::new(tokio_stream::iter(vec![0, 1]));
+    /// map.insert(0, stream);
+    /// map.insert(1, stream2);
+    /// while let Some((key, val)) = map.next().await {
+    ///     match val {
+    ///         Some(val) => println!("got {val:?} from stream {key:?}"),
+    ///         None => println!("stream {key:?} closed"),
     ///     }
     /// }
+    /// # }
     /// ```
     #[must_use = "streams do nothing unless polled"]
     pub struct StreamNotifyClose<S> {
@@ -83,7 +83,7 @@ where
     #[inline]
     fn size_hint(&self) -> (usize, Option<usize>) {
         if let Some(inner) = &self.inner {
-            // We always return +1 because when there's stream there's atleast one more item.
+            // We always return +1 because when there's a stream there's at least one more item.
             let (l, u) = inner.size_hint();
             (l.saturating_add(1), u.and_then(|u| u.checked_add(1)))
         } else {

tokio-stream/src/stream_ext.rs

@@ -129,7 +129,7 @@ pub trait StreamExt: Stream {
     /// # Examples
     ///
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
     /// use tokio_stream::{self as stream, StreamExt};
     ///
@@ -171,8 +171,9 @@ pub trait StreamExt: Stream {
     /// # Examples
     ///
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
+    ///
     /// use tokio_stream::{self as stream, StreamExt};
     ///
     /// let mut stream = stream::iter(vec![Ok(1), Ok(2), Err("nope")]);
@@ -203,7 +204,7 @@ pub trait StreamExt: Stream {
     /// # Examples
     ///
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
     /// use tokio_stream::{self as stream, StreamExt};
     ///
@@ -239,7 +240,7 @@ pub trait StreamExt: Stream {
     /// # Examples
     ///
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
     /// use tokio_stream::{self as stream, StreamExt};
     ///
@@ -283,7 +284,7 @@ pub trait StreamExt: Stream {
     /// # Examples
     ///
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
     /// use tokio_stream::{self as stream, StreamExt};
     ///
@@ -418,7 +419,7 @@ pub trait StreamExt: Stream {
     /// # Examples
     ///
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
     /// use tokio_stream::{self as stream, StreamExt};
     ///
@@ -454,7 +455,7 @@ pub trait StreamExt: Stream {
     ///
     /// # Examples
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
     /// use tokio_stream::{self as stream, StreamExt};
     ///
@@ -514,7 +515,10 @@ pub trait StreamExt: Stream {
     ///     }
     /// }
     ///
+    /// # /*
     /// #[tokio::main]
+    /// # */
+    /// # #[tokio::main(flavor = "current_thread")]
     /// async fn main() {
     ///     let mut stream = Alternate { state: 0 };
     ///
@@ -551,7 +555,7 @@ pub trait StreamExt: Stream {
     /// # Examples
     ///
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
     /// use tokio_stream::{self as stream, StreamExt};
     ///
@@ -580,7 +584,7 @@ pub trait StreamExt: Stream {
     /// # Examples
     ///
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
     /// use tokio_stream::{self as stream, StreamExt};
     ///
@@ -606,7 +610,7 @@ pub trait StreamExt: Stream {
     /// # Examples
     ///
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
     /// use tokio_stream::{self as stream, StreamExt};
     ///
@@ -637,7 +641,7 @@ pub trait StreamExt: Stream {
     /// # Examples
     ///
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
     /// use tokio_stream::{self as stream, StreamExt};
     /// let mut stream = stream::iter(vec![1,2,3,4,1]).skip_while(|x| *x < 3);
@@ -680,7 +684,7 @@ pub trait StreamExt: Stream {
     /// Basic usage:
     ///
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
     /// use tokio_stream::{self as stream, StreamExt};
     ///
@@ -695,7 +699,7 @@ pub trait StreamExt: Stream {
     /// Stopping at the first `false`:
     ///
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
     /// use tokio_stream::{self as stream, StreamExt};
     ///
@@ -739,7 +743,7 @@ pub trait StreamExt: Stream {
     /// Basic usage:
     ///
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
     /// use tokio_stream::{self as stream, StreamExt};
     ///
@@ -754,7 +758,7 @@ pub trait StreamExt: Stream {
     /// Stopping at the first `true`:
     ///
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
     /// use tokio_stream::{self as stream, StreamExt};
     ///
@@ -787,21 +791,21 @@ pub trait StreamExt: Stream {
     /// ```
     /// use tokio_stream::{self as stream, StreamExt};
     ///
-    /// #[tokio::main]
-    /// async fn main() {
-    ///     let one = stream::iter(vec![1, 2, 3]);
-    ///     let two = stream::iter(vec![4, 5, 6]);
+    /// # #[tokio::main(flavor = "current_thread")]
+    /// # async fn main() {
+    /// let one = stream::iter(vec![1, 2, 3]);
+    /// let two = stream::iter(vec![4, 5, 6]);
     ///
-    ///     let mut stream = one.chain(two);
+    /// let mut stream = one.chain(two);
     ///
-    ///     assert_eq!(stream.next().await, Some(1));
-    ///     assert_eq!(stream.next().await, Some(2));
-    ///     assert_eq!(stream.next().await, Some(3));
-    ///     assert_eq!(stream.next().await, Some(4));
-    ///     assert_eq!(stream.next().await, Some(5));
-    ///     assert_eq!(stream.next().await, Some(6));
-    ///     assert_eq!(stream.next().await, None);
-    /// }
+    /// assert_eq!(stream.next().await, Some(1));
+    /// assert_eq!(stream.next().await, Some(2));
+    /// assert_eq!(stream.next().await, Some(3));
+    /// assert_eq!(stream.next().await, Some(4));
+    /// assert_eq!(stream.next().await, Some(5));
+    /// assert_eq!(stream.next().await, Some(6));
+    /// assert_eq!(stream.next().await, None);
+    /// # }
     /// ```
     fn chain<U>(self, other: U) -> Chain<Self, U>
     where
@@ -823,7 +827,7 @@ pub trait StreamExt: Stream {
     /// # Examples
     /// Basic usage:
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
     /// use tokio_stream::{self as stream, *};
     ///
@@ -874,16 +878,16 @@ pub trait StreamExt: Stream {
     /// ```
     /// use tokio_stream::{self as stream, StreamExt};
     ///
-    /// #[tokio::main]
-    /// async fn main() {
-    ///     let doubled: Vec<i32> =
-    ///         stream::iter(vec![1, 2, 3])
-    ///             .map(|x| x * 2)
-    ///             .collect()
-    ///             .await;
+    /// # #[tokio::main(flavor = "current_thread")]
+    /// # async fn main() {
+    /// let doubled: Vec<i32> =
+    ///     stream::iter(vec![1, 2, 3])
+    ///         .map(|x| x * 2)
+    ///         .collect()
+    ///         .await;
     ///
-    ///     assert_eq!(vec![2, 4, 6], doubled);
-    /// }
+    /// assert_eq!(vec![2, 4, 6], doubled);
+    /// # }
     /// ```
     ///
     /// Collecting a stream of `Result` values
@@ -891,28 +895,28 @@ pub trait StreamExt: Stream {
     /// ```
     /// use tokio_stream::{self as stream, StreamExt};
     ///
-    /// #[tokio::main]
-    /// async fn main() {
-    ///     // A stream containing only `Ok` values will be collected
-    ///     let values: Result<Vec<i32>, &str> =
-    ///         stream::iter(vec![Ok(1), Ok(2), Ok(3)])
-    ///             .collect()
-    ///             .await;
+    /// # #[tokio::main(flavor = "current_thread")]
+    /// # async fn main() {
+    /// // A stream containing only `Ok` values will be collected
+    /// let values: Result<Vec<i32>, &str> =
+    ///     stream::iter(vec![Ok(1), Ok(2), Ok(3)])
+    ///         .collect()
+    ///         .await;
     ///
-    ///     assert_eq!(Ok(vec![1, 2, 3]), values);
+    /// assert_eq!(Ok(vec![1, 2, 3]), values);
     ///
-    ///     // A stream containing `Err` values will return the first error.
-    ///     let results = vec![Ok(1), Err("no"), Ok(2), Ok(3), Err("nein")];
+    /// // A stream containing `Err` values will return the first error.
+    /// let results = vec![Ok(1), Err("no"), Ok(2), Ok(3), Err("nein")];
     ///
-    ///     let values: Result<Vec<i32>, &str> =
-    ///         stream::iter(results)
-    ///             .collect()
-    ///             .await;
+    /// let values: Result<Vec<i32>, &str> =
+    ///     stream::iter(results)
+    ///         .collect()
+    ///         .await;
     ///
-    ///     assert_eq!(Err("no"), values);
-    /// }
+    /// assert_eq!(Err("no"), values);
+    /// # }
     /// ```
-    fn collect<T>(self) -> Collect<Self, T>
+    fn collect<T>(self) -> Collect<Self, T, T::InternalCollection>
     where
         T: FromStream<Self::Item>,
         Self: Sized,
@@ -945,7 +949,7 @@ pub trait StreamExt: Stream {
     /// Suppose we have a stream `int_stream` that yields 3 numbers (1, 2, 3):
     ///
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
     /// use tokio_stream::{self as stream, StreamExt};
     /// use std::time::Duration;
@@ -1031,7 +1035,7 @@ pub trait StreamExt: Stream {
     /// Suppose we have a stream `int_stream` that yields 3 numbers (1, 2, 3):
     ///
     /// ```
-    /// # #[tokio::main]
+    /// # #[tokio::main(flavor = "current_thread")]
     /// # async fn main() {
     /// use tokio_stream::{self as stream, StreamExt};
     /// use std::time::Duration;

tokio-stream/src/stream_ext/chain.rs

@@ -3,6 +3,7 @@ use crate::Stream;
 
 use core::pin::Pin;
 use core::task::{ready, Context, Poll};
+use futures_core::FusedStream;
 use pin_project_lite::pin_project;
 
 pin_project! {
@@ -48,3 +49,13 @@ where
         super::merge_size_hints(self.a.size_hint(), self.b.size_hint())
     }
 }
+
+impl<T, U> FusedStream for Chain<T, U>
+where
+    T: Stream,
+    U: FusedStream<Item = T::Item>,
+{
+    fn is_terminated(&self) -> bool {
+        self.a.is_terminated() && self.b.is_terminated()
+    }
+}

tokio-stream/src/stream_ext/chunks_timeout.rs

@@ -33,6 +33,12 @@ impl<S: Stream> ChunksTimeout<S> {
             cap: max_size,
         }
     }
+
+    /// Consumes the [`ChunksTimeout`] and then returns all buffered items.
+    pub fn into_remainder(mut self: Pin<&mut Self>) -> Vec<S::Item> {
+        let me = self.as_mut().project();
+        std::mem::take(me.items)
+    }
 }
 
 impl<S: Stream> Stream for ChunksTimeout<S> {

tokio-stream/src/stream_ext/collect.rs

@@ -1,25 +1,25 @@
 use crate::Stream;
 
 use core::future::Future;
-use core::marker::PhantomPinned;
+use core::marker::{PhantomData, PhantomPinned};
 use core::mem;
 use core::pin::Pin;
 use core::task::{ready, Context, Poll};
 use pin_project_lite::pin_project;
+use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, LinkedList, VecDeque};
+use std::hash::Hash;
 
 // Do not export this struct until `FromStream` can be unsealed.
 pin_project! {
     /// Future returned by the [`collect`](super::StreamExt::collect) method.
     #[must_use = "futures do nothing unless you `.await` or poll them"]
     #[derive(Debug)]
-    pub struct Collect<T, U>
-    where
-        T: Stream,
-        U: FromStream<T::Item>,
+    pub struct Collect<T, U, C>
     {
         #[pin]
         stream: T,
-        collection: U::InternalCollection,
+        collection: C,
+        _output: PhantomData<U>,
         // Make this future `!Unpin` for compatibility with async trait methods.
         #[pin]
         _pin: PhantomPinned,
@@ -38,24 +38,25 @@ pin_project! {
 /// enhancements to the Rust language.
 pub trait FromStream<T>: sealed::FromStreamPriv<T> {}
 
-impl<T, U> Collect<T, U>
+impl<T, U> Collect<T, U, U::InternalCollection>
 where
     T: Stream,
     U: FromStream<T::Item>,
 {
-    pub(super) fn new(stream: T) -> Collect<T, U> {
+    pub(super) fn new(stream: T) -> Collect<T, U, U::InternalCollection> {
         let (lower, upper) = stream.size_hint();
         let collection = U::initialize(sealed::Internal, lower, upper);
 
         Collect {
             stream,
             collection,
+            _output: PhantomData,
             _pin: PhantomPinned,
         }
     }
 }
 
-impl<T, U> Future for Collect<T, U>
+impl<T, U> Future for Collect<T, U, U::InternalCollection>
 where
     T: Stream,
     U: FromStream<T::Item>,
@@ -136,6 +137,139 @@ impl<T> sealed::FromStreamPriv<T> for Vec<T> {
     }
 }
 
+impl<T> FromStream<T> for VecDeque<T> {}
+
+impl<T> sealed::FromStreamPriv<T> for VecDeque<T> {
+    type InternalCollection = VecDeque<T>;
+
+    fn initialize(_: sealed::Internal, lower: usize, _upper: Option<usize>) -> VecDeque<T> {
+        VecDeque::with_capacity(lower)
+    }
+
+    fn extend(_: sealed::Internal, collection: &mut VecDeque<T>, item: T) -> bool {
+        collection.push_back(item);
+        true
+    }
+
+    fn finalize(_: sealed::Internal, collection: &mut VecDeque<T>) -> VecDeque<T> {
+        mem::take(collection)
+    }
+}
+
+impl<T> FromStream<T> for LinkedList<T> {}
+
+impl<T> sealed::FromStreamPriv<T> for LinkedList<T> {
+    type InternalCollection = LinkedList<T>;
+
+    fn initialize(_: sealed::Internal, _lower: usize, _upper: Option<usize>) -> LinkedList<T> {
+        LinkedList::new()
+    }
+
+    fn extend(_: sealed::Internal, collection: &mut LinkedList<T>, item: T) -> bool {
+        collection.push_back(item);
+        true
+    }
+
+    fn finalize(_: sealed::Internal, collection: &mut LinkedList<T>) -> LinkedList<T> {
+        mem::take(collection)
+    }
+}
+
+impl<T: Ord> FromStream<T> for BTreeSet<T> {}
+
+impl<T: Ord> sealed::FromStreamPriv<T> for BTreeSet<T> {
+    type InternalCollection = BTreeSet<T>;
+
+    fn initialize(_: sealed::Internal, _lower: usize, _upper: Option<usize>) -> BTreeSet<T> {
+        BTreeSet::new()
+    }
+
+    fn extend(_: sealed::Internal, collection: &mut BTreeSet<T>, item: T) -> bool {
+        collection.insert(item);
+        true
+    }
+
+    fn finalize(_: sealed::Internal, collection: &mut BTreeSet<T>) -> BTreeSet<T> {
+        mem::take(collection)
+    }
+}
+
+impl<K: Ord, V> FromStream<(K, V)> for BTreeMap<K, V> {}
+
+impl<K: Ord, V> sealed::FromStreamPriv<(K, V)> for BTreeMap<K, V> {
+    type InternalCollection = BTreeMap<K, V>;
+
+    fn initialize(_: sealed::Internal, _lower: usize, _upper: Option<usize>) -> BTreeMap<K, V> {
+        BTreeMap::new()
+    }
+
+    fn extend(_: sealed::Internal, collection: &mut BTreeMap<K, V>, (key, value): (K, V)) -> bool {
+        collection.insert(key, value);
+        true
+    }
+
+    fn finalize(_: sealed::Internal, collection: &mut BTreeMap<K, V>) -> BTreeMap<K, V> {
+        mem::take(collection)
+    }
+}
+
+impl<T: Eq + Hash> FromStream<T> for HashSet<T> {}
+
+impl<T: Eq + Hash> sealed::FromStreamPriv<T> for HashSet<T> {
+    type InternalCollection = HashSet<T>;
+
+    fn initialize(_: sealed::Internal, lower: usize, _upper: Option<usize>) -> HashSet<T> {
+        HashSet::with_capacity(lower)
+    }
+
+    fn extend(_: sealed::Internal, collection: &mut HashSet<T>, item: T) -> bool {
+        collection.insert(item);
+        true
+    }
+
+    fn finalize(_: sealed::Internal, collection: &mut HashSet<T>) -> HashSet<T> {
+        mem::take(collection)
+    }
+}
+
+impl<K: Eq + Hash, V> FromStream<(K, V)> for HashMap<K, V> {}
+
+impl<K: Eq + Hash, V> sealed::FromStreamPriv<(K, V)> for HashMap<K, V> {
+    type InternalCollection = HashMap<K, V>;
+
+    fn initialize(_: sealed::Internal, lower: usize, _upper: Option<usize>) -> HashMap<K, V> {
+        HashMap::with_capacity(lower)
+    }
+
+    fn extend(_: sealed::Internal, collection: &mut HashMap<K, V>, (key, value): (K, V)) -> bool {
+        collection.insert(key, value);
+        true
+    }
+
+    fn finalize(_: sealed::Internal, collection: &mut HashMap<K, V>) -> HashMap<K, V> {
+        mem::take(collection)
+    }
+}
+
+impl<T: Ord> FromStream<T> for BinaryHeap<T> {}
+
+impl<T: Ord> sealed::FromStreamPriv<T> for BinaryHeap<T> {
+    type InternalCollection = BinaryHeap<T>;
+
+    fn initialize(_: sealed::Internal, lower: usize, _upper: Option<usize>) -> BinaryHeap<T> {
+        BinaryHeap::with_capacity(lower)
+    }
+
+    fn extend(_: sealed::Internal, collection: &mut BinaryHeap<T>, item: T) -> bool {
+        collection.push(item);
+        true
+    }
+
+    fn finalize(_: sealed::Internal, collection: &mut BinaryHeap<T>) -> BinaryHeap<T> {
+        mem::take(collection)
+    }
+}
+
 impl<T> FromStream<T> for Box<[T]> {}
 
 impl<T> sealed::FromStreamPriv<T> for Box<[T]> {

tokio-stream/src/stream_ext/filter.rs

@@ -3,6 +3,7 @@ use crate::Stream;
 use core::fmt;
 use core::pin::Pin;
 use core::task::{ready, Context, Poll};
+use futures_core::FusedStream;
 use pin_project_lite::pin_project;
 
 pin_project! {
@@ -56,3 +57,13 @@ where
         (0, self.stream.size_hint().1) // can't know a lower bound, due to the predicate
     }
 }
+
+impl<St, F> FusedStream for Filter<St, F>
+where
+    St: FusedStream,
+    F: FnMut(&St::Item) -> bool,
+{
+    fn is_terminated(&self) -> bool {
+        self.stream.is_terminated()
+    }
+}

tokio-stream/src/stream_ext/filter_map.rs

@@ -3,6 +3,7 @@ use crate::Stream;
 use core::fmt;
 use core::pin::Pin;
 use core::task::{ready, Context, Poll};
+use futures_core::FusedStream;
 use pin_project_lite::pin_project;
 
 pin_project! {
@@ -56,3 +57,13 @@ where
         (0, self.stream.size_hint().1) // can't know a lower bound, due to the predicate
     }
 }
+
+impl<St, F, T> FusedStream for FilterMap<St, F>
+where
+    St: FusedStream,
+    F: FnMut(St::Item) -> Option<T>,
+{
+    fn is_terminated(&self) -> bool {
+        self.stream.is_terminated()
+    }
+}

tokio-stream/src/stream_ext/fuse.rs

@@ -1,5 +1,6 @@
 use crate::Stream;
 
+use futures_core::FusedStream;
 use pin_project_lite::pin_project;
 use std::pin::Pin;
 use std::task::{ready, Context, Poll};
@@ -51,3 +52,12 @@ where
         }
     }
 }
+
+impl<T> FusedStream for Fuse<T>
+where
+    T: Stream,
+{
+    fn is_terminated(&self) -> bool {
+        self.stream.is_none()
+    }
+}

tokio-stream/src/stream_ext/map.rs

@@ -3,6 +3,7 @@ use crate::Stream;
 use core::fmt;
 use core::pin::Pin;
 use core::task::{Context, Poll};
+use futures_core::FusedStream;
 use pin_project_lite::pin_project;
 
 pin_project! {
@@ -49,3 +50,13 @@ where
         self.stream.size_hint()
     }
 }
+
+impl<St, F, T> FusedStream for Map<St, F>
+where
+    St: FusedStream,
+    F: FnMut(St::Item) -> T,
+{
+    fn is_terminated(&self) -> bool {
+        self.stream.is_terminated()
+    }
+}

tokio-stream/src/stream_ext/merge.rs

@@ -3,6 +3,7 @@ use crate::Stream;
 
 use core::pin::Pin;
 use core::task::{Context, Poll};
+use futures_core::FusedStream;
 use pin_project_lite::pin_project;
 
 pin_project! {
@@ -57,6 +58,16 @@ where
     }
 }
 
+impl<T, U> FusedStream for Merge<T, U>
+where
+    T: Stream,
+    U: Stream<Item = T::Item>,
+{
+    fn is_terminated(&self) -> bool {
+        self.a.is_terminated() && self.b.is_terminated()
+    }
+}
+
 fn poll_next<T, U>(
     first: Pin<&mut T>,
     second: Pin<&mut U>,

tokio-stream/src/stream_ext/skip.rs

@@ -3,6 +3,7 @@ use crate::Stream;
 use core::fmt;
 use core::pin::Pin;
 use core::task::{ready, Context, Poll};
+use futures_core::FusedStream;
 use pin_project_lite::pin_project;
 
 pin_project! {
@@ -61,3 +62,12 @@ where
         (lower, upper)
     }
 }
+
+impl<St> FusedStream for Skip<St>
+where
+    St: FusedStream,
+{
+    fn is_terminated(&self) -> bool {
+        self.stream.is_terminated()
+    }
+}

tokio-stream/src/stream_ext/skip_while.rs

@@ -3,6 +3,7 @@ use crate::Stream;
 use core::fmt;
 use core::pin::Pin;
 use core::task::{ready, Context, Poll};
+use futures_core::FusedStream;
 use pin_project_lite::pin_project;
 
 pin_project! {
@@ -71,3 +72,13 @@ where
         (lower, upper)
     }
 }
+
+impl<St, F> FusedStream for SkipWhile<St, F>
+where
+    St: FusedStream,
+    F: FnMut(&St::Item) -> bool,
+{
+    fn is_terminated(&self) -> bool {
+        self.stream.is_terminated()
+    }
+}

tokio-stream/src/stream_ext/take.rs

@@ -4,6 +4,7 @@ use core::cmp;
 use core::fmt;
 use core::pin::Pin;
 use core::task::{Context, Poll};
+use futures_core::FusedStream;
 use pin_project_lite::pin_project;
 
 pin_project! {
@@ -74,3 +75,12 @@ where
         (lower, upper)
     }
 }
+
+impl<St> FusedStream for Take<St>
+where
+    St: Stream,
+{
+    fn is_terminated(&self) -> bool {
+        self.remaining == 0
+    }
+}

tokio-stream/src/stream_ext/take_while.rs

@@ -3,6 +3,7 @@ use crate::Stream;
 use core::fmt;
 use core::pin::Pin;
 use core::task::{Context, Poll};
+use futures_core::FusedStream;
 use pin_project_lite::pin_project;
 
 pin_project! {
@@ -77,3 +78,13 @@ where
         (0, upper)
     }
 }
+
+impl<St, F> FusedStream for TakeWhile<St, F>
+where
+    St: Stream,
+    F: FnMut(&St::Item) -> bool,
+{
+    fn is_terminated(&self) -> bool {
+        self.done
+    }
+}

tokio-stream/src/stream_ext/then.rs

@@ -4,6 +4,7 @@ use core::fmt;
 use core::future::Future;
 use core::pin::Pin;
 use core::task::{Context, Poll};
+use futures_core::FusedStream;
 use pin_project_lite::pin_project;
 
 pin_project! {
@@ -81,3 +82,14 @@ where
         (lower, upper)
     }
 }
+
+impl<St, F, Fut> FusedStream for Then<St, Fut, F>
+where
+    St: FusedStream,
+    Fut: Future,
+    F: FnMut(St::Item) -> Fut,
+{
+    fn is_terminated(&self) -> bool {
+        self.future.is_none() && self.stream.is_terminated()
+    }
+}

tokio-stream/src/stream_map.rs

@@ -65,57 +65,57 @@ use std::task::{ready, Context, Poll};
 /// use tokio::sync::mpsc;
 /// use std::pin::Pin;
 ///
-/// #[tokio::main]
-/// async fn main() {
-///     let (tx1, mut rx1) = mpsc::channel::<usize>(10);
-///     let (tx2, mut rx2) = mpsc::channel::<usize>(10);
+/// # #[tokio::main(flavor = "current_thread")]
+/// # async fn main() {
+/// let (tx1, mut rx1) = mpsc::channel::<usize>(10);
+/// let (tx2, mut rx2) = mpsc::channel::<usize>(10);
 ///
-///     // Convert the channels to a `Stream`.
-///     let rx1 = Box::pin(async_stream::stream! {
-///           while let Some(item) = rx1.recv().await {
-///               yield item;
-///           }
-///     }) as Pin<Box<dyn Stream<Item = usize> + Send>>;
-///
-///     let rx2 = Box::pin(async_stream::stream! {
-///           while let Some(item) = rx2.recv().await {
-///               yield item;
-///           }
-///     }) as Pin<Box<dyn Stream<Item = usize> + Send>>;
-///
-///     tokio::spawn(async move {
-///         tx1.send(1).await.unwrap();
-///
-///         // This value will never be received. The send may or may not return
-///         // `Err` depending on if the remote end closed first or not.
-///         let _ = tx1.send(2).await;
-///     });
-///
-///     tokio::spawn(async move {
-///         tx2.send(3).await.unwrap();
-///         let _ = tx2.send(4).await;
-///     });
-///
-///     let mut map = StreamMap::new();
-///
-///     // Insert both streams
-///     map.insert("one", rx1);
-///     map.insert("two", rx2);
-///
-///     // Read twice
-///     for _ in 0..2 {
-///         let (key, val) = map.next().await.unwrap();
-///
-///         if key == "one" {
-///             assert_eq!(val, 1);
-///         } else {
-///             assert_eq!(val, 3);
-///         }
-///
-///         // Remove the stream to prevent reading the next value
-///         map.remove(key);
+/// // Convert the channels to a `Stream`.
+/// let rx1 = Box::pin(async_stream::stream! {
+///     while let Some(item) = rx1.recv().await {
+///         yield item;
 ///     }
+/// }) as Pin<Box<dyn Stream<Item = usize> + Send>>;
+///
+/// let rx2 = Box::pin(async_stream::stream! {
+///     while let Some(item) = rx2.recv().await {
+///         yield item;
+///     }
+/// }) as Pin<Box<dyn Stream<Item = usize> + Send>>;
+///
+/// tokio::spawn(async move {
+///     tx1.send(1).await.unwrap();
+///
+///     // This value will never be received. The send may or may not return
+///     // `Err` depending on if the remote end closed first or not.
+///     let _ = tx1.send(2).await;
+/// });
+///
+/// tokio::spawn(async move {
+///     tx2.send(3).await.unwrap();
+///     let _ = tx2.send(4).await;
+/// });
+///
+/// let mut map = StreamMap::new();
+///
+/// // Insert both streams
+/// map.insert("one", rx1);
+/// map.insert("two", rx2);
+///
+/// // Read twice
+/// for _ in 0..2 {
+///     let (key, val) = map.next().await.unwrap();
+///
+///     if key == "one" {
+///         assert_eq!(val, 1);
+///     } else {
+///         assert_eq!(val, 3);
+///     }
+///
+///     // Remove the stream to prevent reading the next value
+///     map.remove(key);
 /// }
+/// # }
 /// ```
 ///
 /// This example models a read-only client to a chat system with channels. The
@@ -185,20 +185,20 @@ use std::task::{ready, Context, Poll};
 /// ```
 /// use tokio_stream::{StreamExt, StreamMap, StreamNotifyClose};
 ///
-/// #[tokio::main]
-/// async fn main() {
-///     let mut map = StreamMap::new();
-///     let stream = StreamNotifyClose::new(tokio_stream::iter(vec![0, 1]));
-///     let stream2 = StreamNotifyClose::new(tokio_stream::iter(vec![0, 1]));
-///     map.insert(0, stream);
-///     map.insert(1, stream2);
-///     while let Some((key, val)) = map.next().await {
-///         match val {
-///             Some(val) => println!("got {val:?} from stream {key:?}"),
-///             None => println!("stream {key:?} closed"),
-///         }
+/// # #[tokio::main(flavor = "current_thread")]
+/// # async fn main() {
+/// let mut map = StreamMap::new();
+/// let stream = StreamNotifyClose::new(tokio_stream::iter(vec![0, 1]));
+/// let stream2 = StreamNotifyClose::new(tokio_stream::iter(vec![0, 1]));
+/// map.insert(0, stream);
+/// map.insert(1, stream2);
+/// while let Some((key, val)) = map.next().await {
+///     match val {
+///         Some(val) => println!("got {val:?} from stream {key:?}"),
+///         None => println!("stream {key:?} closed"),
 ///     }
 /// }
+/// # }
 /// ```
 
 #[derive(Debug)]
@@ -579,9 +579,11 @@ where
     /// # Cancel safety
     ///
     /// This method is cancel safe. If `next_many` is used as the event in a
-    /// [`tokio::select!`](tokio::select) statement and some other branch
-    /// completes first, it is guaranteed that no items were received on any of
-    /// the underlying streams.
+    /// [`tokio::select!`] statement and some other branch completes first,
+    /// it is guaranteed that no items were received on any of the underlying
+    /// streams.
+    ///
+    /// [`tokio::select!`]: https://docs.rs/tokio/latest/tokio/macro.select.html
     pub async fn next_many(&mut self, buffer: &mut Vec<(K, V::Item)>, limit: usize) -> usize {
         poll_fn(|cx| self.poll_next_many(cx, buffer, limit)).await
     }
@@ -734,22 +736,15 @@ mod rand {
         #[cfg(not(loom))]
         pub(crate) mod rand {
             use std::collections::hash_map::RandomState;
-            use std::hash::{BuildHasher, Hash, Hasher};
+            use std::hash::BuildHasher;
             use std::sync::atomic::AtomicU32;
             use std::sync::atomic::Ordering::Relaxed;
 
             static COUNTER: AtomicU32 = AtomicU32::new(1);
 
             pub(crate) fn seed() -> u64 {
-                let rand_state = RandomState::new();
-
-                let mut hasher = rand_state.build_hasher();
-
                 // Hash some unique-ish data to generate some new state
-                COUNTER.fetch_add(1, Relaxed).hash(&mut hasher);
-
-                // Get the seed
-                hasher.finish()
+                RandomState::new().hash_one(COUNTER.fetch_add(1, Relaxed))
             }
         }
 

tokio-stream/src/wrappers.rs

@@ -22,9 +22,9 @@ cfg_sync! {
 }
 
 cfg_signal! {
-    #[cfg(unix)]
+    #[cfg(all(unix, not(loom)))]
     mod signal_unix;
-    #[cfg(unix)]
+    #[cfg(all(unix, not(loom)))]
     pub use signal_unix::SignalStream;
 
     #[cfg(any(windows, docsrs))]
@@ -39,12 +39,14 @@ cfg_time! {
 }
 
 cfg_net! {
+    #[cfg(not(loom))]
     mod tcp_listener;
+    #[cfg(not(loom))]
     pub use tcp_listener::TcpListenerStream;
 
-    #[cfg(unix)]
+    #[cfg(all(unix, not(loom)))]
     mod unix_listener;
-    #[cfg(unix)]
+    #[cfg(all(unix, not(loom)))]
     pub use unix_listener::UnixListenerStream;
 }
 
@@ -57,6 +59,8 @@ cfg_io_util! {
 }
 
 cfg_fs! {
+    #[cfg(not(loom))]
     mod read_dir;
+    #[cfg(not(loom))]
     pub use read_dir::ReadDirStream;
 }

tokio-stream/src/wrappers/broadcast.rs

@@ -53,7 +53,7 @@ pub enum BroadcastStreamRecvError {
 impl fmt::Display for BroadcastStreamRecvError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
-            BroadcastStreamRecvError::Lagged(amt) => write!(f, "channel lagged by {}", amt),
+            BroadcastStreamRecvError::Lagged(amt) => write!(f, "channel lagged by {amt}"),
         }
     }
 }

tokio-stream/src/wrappers/interval.rs

@@ -1,4 +1,5 @@
 use crate::Stream;
+use futures_core::stream::FusedStream;
 use std::pin::Pin;
 use std::task::{Context, Poll};
 use tokio::time::{Instant, Interval};
@@ -57,6 +58,12 @@ impl Stream for IntervalStream {
     }
 }
 
+impl FusedStream for IntervalStream {
+    fn is_terminated(&self) -> bool {
+        false
+    }
+}
+
 impl AsRef<Interval> for IntervalStream {
     fn as_ref(&self) -> &Interval {
         &self.inner

tokio-stream/src/wrappers/mpsc_bounded.rs

@@ -67,6 +67,25 @@ impl<T> Stream for ReceiverStream<T> {
     fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
         self.inner.poll_recv(cx)
     }
+
+    /// Returns the bounds of the stream based on the underlying receiver.
+    ///
+    /// For open channels, it returns `(receiver.len(), None)`.
+    ///
+    /// For closed channels, it returns `(receiver.len(), Some(used_capacity))`
+    /// where `used_capacity` is calculated as `receiver.max_capacity() -
+    /// receiver.capacity()`. This accounts for any [`Permit`] that is still
+    /// able to send a message.
+    ///
+    /// [`Permit`]: struct@tokio::sync::mpsc::Permit
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        if self.inner.is_closed() {
+            let used_capacity = self.inner.max_capacity() - self.inner.capacity();
+            (self.inner.len(), Some(used_capacity))
+        } else {
+            (self.inner.len(), None)
+        }
+    }
 }
 
 impl<T> AsRef<Receiver<T>> for ReceiverStream<T> {

tokio-stream/src/wrappers/mpsc_unbounded.rs

@@ -61,6 +61,20 @@ impl<T> Stream for UnboundedReceiverStream<T> {
     fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
         self.inner.poll_recv(cx)
     }
+
+    /// Returns the bounds of the stream based on the underlying receiver.
+    ///
+    /// For open channels, it returns `(receiver.len(), None)`.
+    ///
+    /// For closed channels, it returns `(receiver.len(), receiver.len())`.
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        if self.inner.is_closed() {
+            let len = self.inner.len();
+            (len, Some(len))
+        } else {
+            (self.inner.len(), None)
+        }
+    }
 }
 
 impl<T> AsRef<UnboundedReceiver<T>> for UnboundedReceiverStream<T> {

tokio-stream/src/wrappers/tcp_listener.rs

@@ -11,6 +11,8 @@ use tokio::net::{TcpListener, TcpStream};
 /// Accept connections from both IPv4 and IPv6 listeners in the same loop:
 ///
 /// ```no_run
+/// # #[cfg(not(target_family = "wasm"))]
+/// # {
 /// use std::net::{Ipv4Addr, Ipv6Addr};
 ///
 /// use tokio::net::TcpListener;
@@ -18,12 +20,12 @@ use tokio::net::{TcpListener, TcpStream};
 ///
 /// # #[tokio::main(flavor = "current_thread")]
 /// # async fn main() -> std::io::Result<()> {
-/// let ipv4_listener = TcpListener::bind((Ipv6Addr::LOCALHOST, 8080)).await?;
-/// let ipv6_listener = TcpListener::bind((Ipv4Addr::LOCALHOST, 8080)).await?;
+/// let ipv4_listener = TcpListener::bind((Ipv4Addr::LOCALHOST, 8080)).await?;
+/// let ipv6_listener = TcpListener::bind((Ipv6Addr::LOCALHOST, 8080)).await?;
 /// let ipv4_connections = TcpListenerStream::new(ipv4_listener);
 /// let ipv6_connections = TcpListenerStream::new(ipv6_listener);
 ///
-/// let mut connections = ipv4_connections.chain(ipv6_connections);
+/// let mut connections = ipv4_connections.merge(ipv6_connections);
 /// while let Some(tcp_stream) = connections.next().await {
 ///     let stream = tcp_stream?;
 ///     let peer_addr = stream.peer_addr()?;
@@ -31,6 +33,7 @@ use tokio::net::{TcpListener, TcpStream};
 /// }
 /// # Ok(())
 /// # }
+/// # }
 /// ```
 ///
 /// [`TcpListener`]: struct@tokio::net::TcpListener

tokio-stream/src/wrappers/watch.rs

@@ -17,7 +17,7 @@ use tokio::sync::watch::error::RecvError;
 /// # Examples
 ///
 /// ```
-/// # #[tokio::main]
+/// # #[tokio::main(flavor = "current_thread")]
 /// # async fn main() {
 /// use tokio_stream::{StreamExt, wrappers::WatchStream};
 /// use tokio::sync::watch;
@@ -33,7 +33,7 @@ use tokio::sync::watch::error::RecvError;
 /// ```
 ///
 /// ```
-/// # #[tokio::main]
+/// # #[tokio::main(flavor = "current_thread")]
 /// # async fn main() {
 /// use tokio_stream::{StreamExt, wrappers::WatchStream};
 /// use tokio::sync::watch;
@@ -51,7 +51,7 @@ use tokio::sync::watch::error::RecvError;
 /// Example with [`WatchStream<T>::from_changes`]:
 ///
 /// ```
-/// # #[tokio::main]
+/// # #[tokio::main(flavor = "current_thread")]
 /// # async fn main() {
 /// use futures::future::FutureExt;
 /// use tokio::sync::watch;

tokio-stream/tests/mpsc_bounded_stream.rs

@@ -0,0 +1,109 @@
+use futures::{Stream, StreamExt};
+use tokio::sync::mpsc;
+use tokio_stream::wrappers::ReceiverStream;
+
+#[tokio::test]
+async fn size_hint_stream_open() {
+    let (tx, rx) = mpsc::channel(4);
+
+    tx.send(1).await.unwrap();
+    tx.send(2).await.unwrap();
+
+    let mut stream = ReceiverStream::new(rx);
+
+    assert_eq!(stream.size_hint(), (2, None));
+    stream.next().await;
+    assert_eq!(stream.size_hint(), (1, None));
+    stream.next().await;
+    assert_eq!(stream.size_hint(), (0, None));
+}
+
+#[tokio::test]
+async fn size_hint_stream_closed() {
+    let (tx, rx) = mpsc::channel(4);
+
+    tx.send(1).await.unwrap();
+    tx.send(2).await.unwrap();
+
+    let mut stream = ReceiverStream::new(rx);
+    stream.close();
+
+    assert_eq!(stream.size_hint(), (2, Some(2)));
+    stream.next().await;
+    assert_eq!(stream.size_hint(), (1, Some(1)));
+    stream.next().await;
+    assert_eq!(stream.size_hint(), (0, Some(0)));
+}
+
+#[tokio::test]
+async fn size_hint_sender_dropped() {
+    let (tx, rx) = mpsc::channel(4);
+
+    tx.send(1).await.unwrap();
+    tx.send(2).await.unwrap();
+
+    let mut stream = ReceiverStream::new(rx);
+    drop(tx);
+
+    assert_eq!(stream.size_hint(), (2, Some(2)));
+    stream.next().await;
+    assert_eq!(stream.size_hint(), (1, Some(1)));
+    stream.next().await;
+    assert_eq!(stream.size_hint(), (0, Some(0)));
+}
+
+#[test]
+fn size_hint_stream_instantly_closed() {
+    let (_tx, rx) = mpsc::channel::<i32>(4);
+
+    let mut stream = ReceiverStream::new(rx);
+    stream.close();
+
+    assert_eq!(stream.size_hint(), (0, Some(0)));
+}
+
+#[tokio::test]
+async fn size_hint_stream_closed_permits_send() {
+    let (tx, rx) = mpsc::channel(4);
+
+    tx.send(1).await.unwrap();
+    let permit1 = tx.reserve().await.unwrap();
+    let permit2 = tx.reserve().await.unwrap();
+
+    let mut stream = ReceiverStream::new(rx);
+    stream.close();
+
+    assert_eq!(stream.size_hint(), (1, Some(3)));
+    permit1.send(2);
+    assert_eq!(stream.size_hint(), (2, Some(3)));
+    stream.next().await;
+    assert_eq!(stream.size_hint(), (1, Some(2)));
+    stream.next().await;
+    assert_eq!(stream.size_hint(), (0, Some(1)));
+    permit2.send(3);
+    assert_eq!(stream.size_hint(), (1, Some(1)));
+    stream.next().await;
+    assert_eq!(stream.size_hint(), (0, Some(0)));
+    assert_eq!(stream.next().await, None);
+}
+
+#[tokio::test]
+async fn size_hint_stream_closed_permits_drop() {
+    let (tx, rx) = mpsc::channel(4);
+
+    tx.send(1).await.unwrap();
+    let permit1 = tx.reserve().await.unwrap();
+    let permit2 = tx.reserve().await.unwrap();
+
+    let mut stream = ReceiverStream::new(rx);
+    stream.close();
+
+    assert_eq!(stream.size_hint(), (1, Some(3)));
+    drop(permit1);
+    assert_eq!(stream.size_hint(), (1, Some(2)));
+    stream.next().await;
+    assert_eq!(stream.size_hint(), (0, Some(1)));
+    drop(permit2);
+    assert_eq!(stream.size_hint(), (0, Some(0)));
+    assert_eq!(stream.next().await, None);
+}

tokio-stream/tests/mpsc_unbounded_stream.rs

@@ -0,0 +1,63 @@
+use futures::{Stream, StreamExt};
+use tokio::sync::mpsc;
+use tokio_stream::wrappers::UnboundedReceiverStream;
+
+#[tokio::test]
+async fn size_hint_stream_open() {
+    let (tx, rx) = mpsc::unbounded_channel();
+
+    tx.send(1).unwrap();
+    tx.send(2).unwrap();
+
+    let mut stream = UnboundedReceiverStream::new(rx);
+
+    assert_eq!(stream.size_hint(), (2, None));
+    stream.next().await;
+    assert_eq!(stream.size_hint(), (1, None));
+    stream.next().await;
+    assert_eq!(stream.size_hint(), (0, None));
+}
+
+#[tokio::test]
+async fn size_hint_stream_closed() {
+    let (tx, rx) = mpsc::unbounded_channel();
+
+    tx.send(1).unwrap();
+    tx.send(2).unwrap();
+
+    let mut stream = UnboundedReceiverStream::new(rx);
+    stream.close();
+
+    assert_eq!(stream.size_hint(), (2, Some(2)));
+    stream.next().await;
+    assert_eq!(stream.size_hint(), (1, Some(1)));
+    stream.next().await;
+    assert_eq!(stream.size_hint(), (0, Some(0)));
+}
+
+#[tokio::test]
+async fn size_hint_sender_dropped() {
+    let (tx, rx) = mpsc::unbounded_channel();
+
+    tx.send(1).unwrap();
+    tx.send(2).unwrap();
+
+    let mut stream = UnboundedReceiverStream::new(rx);
+    drop(tx);
+
+    assert_eq!(stream.size_hint(), (2, Some(2)));
+    stream.next().await;
+    assert_eq!(stream.size_hint(), (1, Some(1)));
+    stream.next().await;
+    assert_eq!(stream.size_hint(), (0, Some(0)));
+}
+
+#[test]
+fn size_hint_stream_instantly_closed() {
+    let (_tx, rx) = mpsc::unbounded_channel::<i32>();
+
+    let mut stream = UnboundedReceiverStream::new(rx);
+    stream.close();
+
+    assert_eq!(stream.size_hint(), (0, Some(0)));
+}

tokio-stream/tests/stream_chunks_timeout.rs

@@ -0,0 +1,30 @@
+#![warn(rust_2018_idioms)]
+
+use futures::FutureExt;
+use std::error::Error;
+use tokio::time;
+use tokio::time::Duration;
+use tokio_stream::{self as stream, StreamExt};
+use tokio_test::assert_pending;
+use tokio_test::task;
+
+#[tokio::test(start_paused = true)]
+async fn stream_chunks_remainder() -> Result<(), Box<dyn Error>> {
+    let stream1 =
+        stream::iter([5]).then(move |n| time::sleep(Duration::from_secs(1)).map(move |_| n));
+
+    let inner = stream::iter([1, 2, 3, 4]).chain(stream1);
+    tokio::pin!(inner);
+
+    let chunked = (&mut inner).chunks_timeout(10, Duration::from_millis(20));
+
+    let mut chunked = task::spawn(chunked);
+    assert_pending!(chunked.poll_next());
+
+    let remainder = chunked.enter(|_, stream| stream.into_remainder());
+
+    assert_eq!(remainder, vec![1, 2, 3, 4]);
+    time::advance(Duration::from_secs(2)).await;
+    assert_eq!(inner.next().await, Some(5));
+    Ok(())
+}

tokio-stream/tests/stream_collect.rs

@@ -1,3 +1,5 @@
+use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, LinkedList, VecDeque};
+
 use tokio_stream::{self as stream, StreamExt};
 use tokio_test::{assert_pending, assert_ready, assert_ready_err, assert_ready_ok, task};
 
@@ -61,6 +63,155 @@ async fn collect_vec_items() {
     assert_eq!(vec![1, 2], coll);
 }
 
+#[tokio::test]
+async fn collect_vecdeque_items() {
+    let (tx, rx) = mpsc::unbounded_channel_stream();
+    let mut fut = task::spawn(rx.collect::<VecDeque<i32>>());
+
+    assert_pending!(fut.poll());
+
+    let xs = [1, 2, 42, 3];
+    for x in xs {
+        tx.send(x).unwrap();
+        assert!(fut.is_woken());
+        assert_pending!(fut.poll());
+    }
+
+    drop(tx);
+    assert!(fut.is_woken());
+    let coll = assert_ready!(fut.poll());
+
+    assert_eq!(coll, VecDeque::from(xs));
+    assert_eq!(coll.into_iter().collect::<Vec<_>>(), xs);
+}
+
+#[tokio::test]
+async fn collect_linkedlist_items() {
+    let (tx, rx) = mpsc::unbounded_channel_stream();
+    let mut fut = task::spawn(rx.collect::<LinkedList<i32>>());
+
+    assert_pending!(fut.poll());
+
+    let xs = [1, 2, 42, 3];
+    for x in xs {
+        tx.send(x).unwrap();
+        assert!(fut.is_woken());
+        assert_pending!(fut.poll());
+    }
+
+    drop(tx);
+    assert!(fut.is_woken());
+    let coll = assert_ready!(fut.poll());
+
+    assert_eq!(coll, LinkedList::from(xs));
+    assert_eq!(coll.into_iter().collect::<Vec<_>>(), xs);
+}
+
+#[tokio::test]
+async fn collect_btreeset_items() {
+    let (tx, rx) = mpsc::unbounded_channel_stream();
+    let mut fut = task::spawn(rx.collect::<BTreeSet<i32>>());
+
+    assert_pending!(fut.poll());
+
+    tx.send(2).unwrap();
+    assert!(fut.is_woken());
+    assert_pending!(fut.poll());
+
+    tx.send(1).unwrap();
+    assert!(fut.is_woken());
+    assert_pending!(fut.poll());
+
+    drop(tx);
+    assert!(fut.is_woken());
+    let coll = assert_ready!(fut.poll());
+    assert_eq!(BTreeSet::from([1, 2]), coll);
+}
+
+#[tokio::test]
+async fn collect_btreemap_items() {
+    let (tx, rx) = mpsc::unbounded_channel_stream();
+    let mut fut = task::spawn(rx.collect::<BTreeMap<i32, i32>>());
+
+    assert_pending!(fut.poll());
+
+    tx.send((3, 4)).unwrap();
+    assert!(fut.is_woken());
+    assert_pending!(fut.poll());
+
+    tx.send((1, 2)).unwrap();
+    assert!(fut.is_woken());
+    assert_pending!(fut.poll());
+
+    drop(tx);
+    assert!(fut.is_woken());
+    let coll = assert_ready!(fut.poll());
+    assert_eq!(BTreeMap::from([(1, 2), (3, 4)]), coll);
+}
+
+#[tokio::test]
+async fn collect_hashset_items() {
+    let (tx, rx) = mpsc::unbounded_channel_stream();
+    let mut fut = task::spawn(rx.collect::<HashSet<i32>>());
+
+    assert_pending!(fut.poll());
+
+    tx.send(1).unwrap();
+    assert!(fut.is_woken());
+    assert_pending!(fut.poll());
+
+    tx.send(2).unwrap();
+    assert!(fut.is_woken());
+    assert_pending!(fut.poll());
+
+    drop(tx);
+    assert!(fut.is_woken());
+    let coll = assert_ready!(fut.poll());
+    assert_eq!(HashSet::from([1, 2]), coll);
+}
+
+#[tokio::test]
+async fn collect_hashmap_items() {
+    let (tx, rx) = mpsc::unbounded_channel_stream();
+    let mut fut = task::spawn(rx.collect::<HashMap<i32, i32>>());
+
+    assert_pending!(fut.poll());
+
+    tx.send((1, 2)).unwrap();
+    assert!(fut.is_woken());
+    assert_pending!(fut.poll());
+
+    tx.send((3, 4)).unwrap();
+    assert!(fut.is_woken());
+    assert_pending!(fut.poll());
+
+    drop(tx);
+    assert!(fut.is_woken());
+    let coll = assert_ready!(fut.poll());
+    assert_eq!(HashMap::from([(1, 2), (3, 4)]), coll);
+}
+
+#[tokio::test]
+async fn collect_binaryheap_items() {
+    let (tx, rx) = mpsc::unbounded_channel_stream();
+    let mut fut = task::spawn(rx.collect::<BinaryHeap<i32>>());
+
+    assert_pending!(fut.poll());
+
+    tx.send(2).unwrap();
+    assert!(fut.is_woken());
+    assert_pending!(fut.poll());
+
+    tx.send(1).unwrap();
+    assert!(fut.is_woken());
+    assert_pending!(fut.poll());
+
+    drop(tx);
+    assert!(fut.is_woken());
+    let coll = assert_ready!(fut.poll());
+    assert_eq!(vec![1, 2], coll.into_sorted_vec());
+}
+
 #[tokio::test]
 async fn collect_string_items() {
     let (tx, rx) = mpsc::unbounded_channel_stream();

tokio-stream/tests/stream_fuse.rs

@@ -1,3 +1,4 @@
+use futures_core::FusedStream;
 use tokio_stream::{Stream, StreamExt};
 
 use std::pin::Pin;
@@ -37,14 +38,32 @@ async fn basic_usage() {
     // however, once it is fused
     let mut stream = stream.fuse();
 
+    assert!(!stream.is_terminated());
     assert_eq!(stream.size_hint(), (0, None));
     assert_eq!(stream.next().await, Some(4));
 
+    assert!(!stream.is_terminated());
     assert_eq!(stream.size_hint(), (0, None));
     assert_eq!(stream.next().await, None);
 
+    assert!(stream.is_terminated());
+
     // it will always return `None` after the first time.
     assert_eq!(stream.size_hint(), (0, Some(0)));
     assert_eq!(stream.next().await, None);
     assert_eq!(stream.size_hint(), (0, Some(0)));
+
+    assert!(stream.is_terminated());
+}
+
+#[tokio::test]
+#[cfg(feature = "time")]
+async fn interval_stream_is_never_terminated() {
+    use futures_core::stream::FusedStream;
+    use tokio_stream::wrappers::IntervalStream;
+
+    let interval = tokio::time::interval(std::time::Duration::from_millis(1));
+    let stream = IntervalStream::new(interval);
+
+    assert!(!stream.is_terminated());
 }

tokio-stream/tests/stream_fused.rs

@@ -0,0 +1,188 @@
+use futures_core::FusedStream;
+use tokio_stream::StreamExt;
+
+// Helper: a fused base stream built from a vec
+fn fused_iter<T>(items: Vec<T>) -> impl FusedStream<Item = T> {
+    tokio_stream::iter(items).fuse()
+}
+
+// ── map ──────────────────────────────────────────────────────────────────────
+
+#[tokio::test]
+async fn map_not_terminated_before_done() {
+    let stream = fused_iter(vec![1, 2]).map(|x| x * 2);
+    assert!(!stream.is_terminated());
+}
+
+#[tokio::test]
+async fn map_terminated_after_inner_done() {
+    let mut stream = fused_iter(vec![1]).map(|x| x * 2);
+    assert_eq!(stream.next().await, Some(2));
+    assert_eq!(stream.next().await, None);
+    assert!(stream.is_terminated());
+}
+
+// ── filter ───────────────────────────────────────────────────────────────────
+
+#[tokio::test]
+async fn filter_not_terminated_before_done() {
+    let stream = fused_iter(vec![1, 2]).filter(|x| *x > 0);
+    assert!(!stream.is_terminated());
+}
+
+#[tokio::test]
+async fn filter_terminated_after_inner_done() {
+    let mut stream = fused_iter(vec![1]).filter(|x| *x > 0);
+    assert_eq!(stream.next().await, Some(1));
+    assert_eq!(stream.next().await, None);
+    assert!(stream.is_terminated());
+}
+
+// ── filter_map ───────────────────────────────────────────────────────────────
+
+#[tokio::test]
+async fn filter_map_not_terminated_before_done() {
+    let stream = fused_iter(vec![1, 2]).filter_map(Some);
+    assert!(!stream.is_terminated());
+}
+
+#[tokio::test]
+async fn filter_map_terminated_after_inner_done() {
+    let mut stream = fused_iter(vec![1]).filter_map(|x| Some(x * 10));
+    assert_eq!(stream.next().await, Some(10));
+    assert_eq!(stream.next().await, None);
+    assert!(stream.is_terminated());
+}
+
+// ── skip ─────────────────────────────────────────────────────────────────────
+
+#[tokio::test]
+async fn skip_not_terminated_before_done() {
+    let stream = fused_iter(vec![1, 2, 3]).skip(1);
+    assert!(!stream.is_terminated());
+}
+
+#[tokio::test]
+async fn skip_terminated_after_inner_done() {
+    let mut stream = fused_iter(vec![1, 2]).skip(1);
+    assert_eq!(stream.next().await, Some(2));
+    assert_eq!(stream.next().await, None);
+    assert!(stream.is_terminated());
+}
+
+// ── skip_while ───────────────────────────────────────────────────────────────
+
+#[tokio::test]
+async fn skip_while_not_terminated_before_done() {
+    let stream = fused_iter(vec![1, 2, 3]).skip_while(|x| *x < 2);
+    assert!(!stream.is_terminated());
+}
+
+#[tokio::test]
+async fn skip_while_terminated_after_inner_done() {
+    let mut stream = fused_iter(vec![1, 2]).skip_while(|x| *x < 2);
+    assert_eq!(stream.next().await, Some(2));
+    assert_eq!(stream.next().await, None);
+    assert!(stream.is_terminated());
+}
+
+// ── take ─────────────────────────────────────────────────────────────────────
+
+#[tokio::test]
+async fn take_not_terminated_before_limit() {
+    let stream = tokio_stream::iter(vec![1, 2, 3]).take(2);
+    assert!(!stream.is_terminated());
+}
+
+#[tokio::test]
+async fn take_terminated_when_remaining_zero() {
+    let mut stream = tokio_stream::iter(vec![1, 2]).take(2);
+    assert_eq!(stream.next().await, Some(1));
+    assert!(!stream.is_terminated());
+    assert_eq!(stream.next().await, Some(2));
+    // remaining hits 0 after getting the second item
+    assert!(stream.is_terminated());
+    assert_eq!(stream.next().await, None);
+}
+
+#[tokio::test]
+async fn take_zero_is_immediately_terminated() {
+    let stream = tokio_stream::iter(vec![1, 2]).take(0);
+    assert!(stream.is_terminated());
+}
+
+// ── take_while ───────────────────────────────────────────────────────────────
+
+#[tokio::test]
+async fn take_while_not_terminated_before_predicate_fails() {
+    let stream = tokio_stream::iter(vec![1, 2, 3]).take_while(|x| *x < 10);
+    assert!(!stream.is_terminated());
+}
+
+#[tokio::test]
+async fn take_while_terminated_after_predicate_fails() {
+    let mut stream = tokio_stream::iter(vec![1, 5, 2]).take_while(|x| *x < 3);
+    assert_eq!(stream.next().await, Some(1));
+    assert!(!stream.is_terminated());
+    // predicate fails on 5 → done flag set
+    assert_eq!(stream.next().await, None);
+    assert!(stream.is_terminated());
+}
+
+// ── then ─────────────────────────────────────────────────────────────────────
+
+#[tokio::test]
+async fn then_not_terminated_before_done() {
+    let stream = fused_iter(vec![1, 2]).then(|x| async move { x * 2 });
+    tokio::pin!(stream);
+    assert!(!stream.is_terminated());
+}
+
+#[tokio::test]
+async fn then_terminated_after_inner_done_and_no_pending_future() {
+    let stream = fused_iter(vec![1]).then(|x| async move { x * 2 });
+    tokio::pin!(stream);
+    assert_eq!(stream.next().await, Some(2));
+    assert_eq!(stream.next().await, None);
+    // inner stream done AND no in-flight future
+    assert!(stream.is_terminated());
+}
+
+// ── chain ────────────────────────────────────────────────────────────────────
+
+#[tokio::test]
+async fn chain_not_terminated_while_either_has_items() {
+    let stream = fused_iter(vec![1]).chain(fused_iter(vec![2]));
+    assert!(!stream.is_terminated());
+}
+
+#[tokio::test]
+async fn chain_terminated_only_after_both_done() {
+    let mut stream = fused_iter(vec![1]).chain(fused_iter(vec![2]));
+    assert_eq!(stream.next().await, Some(1));
+    assert!(!stream.is_terminated()); // b still has items
+    assert_eq!(stream.next().await, Some(2));
+    assert_eq!(stream.next().await, None);
+    assert!(stream.is_terminated()); // both done now
+}
+
+// ── merge ────────────────────────────────────────────────────────────────────
+
+#[tokio::test]
+async fn merge_not_terminated_while_either_has_items() {
+    let stream = fused_iter(vec![1]).merge(fused_iter(vec![2]));
+    assert!(!stream.is_terminated());
+}
+
+#[tokio::test]
+async fn merge_terminated_only_after_both_done() {
+    let mut stream = fused_iter(vec![1]).merge(fused_iter(vec![2]));
+    // drain both
+    let mut collected = vec![];
+    while let Some(x) = stream.next().await {
+        collected.push(x);
+    }
+    assert_eq!(stream.next().await, None);
+    assert!(stream.is_terminated());
+    assert_eq!(collected.len(), 2);
+}

tokio-stream/tests/watch.rs

@@ -12,7 +12,7 @@ async fn watch_stream_message_not_twice() {
 
     let mut counter = 0;
     let mut stream = WatchStream::new(rx).map(move |payload| {
-        println!("{}", payload);
+        println!("{payload}");
         if payload == "goodbye" {
             counter += 1;
         }

tokio-test/CHANGELOG.md

@@ -1,3 +1,21 @@
+# 0.4.5 (January 4th, 2026)
+
+### Added
+
+- test: add `io::Builder::name` for better panic messages ([#7212])
+
+### Fixed
+
+- test: make `Spawn` forward `size_hint` ([#6607])
+
+### Changed
+
+- test: remove unused `async-stream` and `bytes` dependencies ([#7214])
+
+[#6607]: https://github.com/tokio-rs/tokio/pull/6607
+[#7212]: https://github.com/tokio-rs/tokio/pull/7212
+[#7214]: https://github.com/tokio-rs/tokio/pull/7214
+
 # 0.4.4 (March 14, 2024)
 
 - task: mark `Spawn` as `#[must_use]` ([#6371])