chore: prepare Tokio v1.43.3

Signed-off-by: ADD-SP <[email protected]>

.cargo/audit.toml

@@ -1,8 +0,0 @@
-# See https://github.com/rustsec/rustsec/blob/59e1d2ad0b9cbc6892c26de233d4925074b4b97b/cargo-audit/audit.toml.example for example.
-
-[advisories]
-ignore = [
-    # We depend on nix 0.22 only via mio-aio, a dev-dependency.
-    # https://github.com/tokio-rs/tokio/pull/4255#issuecomment-974786349
-    "RUSTSEC-2021-0119",
-]

.cargo/config

@@ -1,2 +0,0 @@
-# [build]
-# rustflags = ["--cfg", "tokio_unstable"]

.circleci/config.yml

@@ -1,8 +1,8 @@
-version: 2.1        
+version: 2.1
 jobs:
   test-arm:
     machine:
-      image: ubuntu-2004:202101-01
+      image: default
     resource_class: arm.medium
     environment:
       # Change to pin rust version

.cirrus.yml

@@ -1,10 +1,10 @@
 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-12-4
+  image_family: freebsd-14-2
 env:
   RUST_STABLE: stable
-  RUST_NIGHTLY: nightly-2022-10-25
+  RUST_NIGHTLY: nightly-2024-05-05
   RUSTFLAGS: -D warnings
 
 # Test FreeBSD in a full VM on cirrus-ci.com.  Test the i686 target too, in the
@@ -14,7 +14,7 @@ env:
 task:
   name: FreeBSD 64-bit
   setup_script:
-    - pkg install -y bash curl
+    - 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
@@ -31,7 +31,7 @@ task:
     RUSTFLAGS: --cfg docsrs --cfg tokio_unstable
     RUSTDOCFLAGS: --cfg docsrs --cfg tokio_unstable -Dwarnings
   setup_script:
-    - pkg install -y bash curl
+    - 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
@@ -45,7 +45,7 @@ task:
 task:
   name: FreeBSD 32-bit
   setup_script:
-    - pkg install -y bash curl
+    - 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

.clippy.toml

@@ -1 +0,0 @@
-msrv = "1.49"

.github/buildomat/README.md

@@ -0,0 +1,20 @@
+# Buildomat illumos CI
+
+This directory contains CI configurations for the [illumos] operating system.
+Tokio's illumos CI jobs are run using [Buildomat], a CI system developed by
+Oxide Computer, which supports illumos. See [the Buildomat README] for more
+details.
+
+## illumos-Specific CI Failures
+
+If your pull request's CI build fails on illumos, and you aren't able to easily
+reproduce the failure on other operating systems, don't worry! The
+[tokio-rs/illumos] team is responsible for maintaining Tokio's illumos support,
+and can be called on to assist contributors with illumos-specific issues. Please
+feel free to tag @tokio-rs/illumos to ask for help resolving build failures on
+illumos.
+
+[illumos]: https://www.illumos.org/
+[Buildomat]: https://github.com/oxidecomputer/buildomat
+[the Buildomat README]: https://github.com/oxidecomputer/buildomat
+[tokio-rs/illumos]: https://github.com/orgs/tokio-rs/teams/illumos

.github/buildomat/config.toml

@@ -0,0 +1,8 @@
+# Repository-level Buildomat configuration.
+# See: https://github.com/oxidecomputer/buildomat#per-repository-configuration
+
+# Enable buildomat. This one should be self-explanatory.
+enable = true
+# Allow CI runs for PRs from users outside the `tokio-rs` organization. Our
+# buildomat jobs don't touch any secrets/keys, so this should be fine.
+org_only = false

.github/labeler.yml

@@ -1,8 +1,28 @@
 
-R-loom:
+R-loom-sync:
 - tokio/src/sync/*
 - tokio/src/sync/**/*
-- tokio-util/src/sync/*
-- tokio-util/src/sync/**/*
-- tokio/src/runtime/*
-- tokio/src/runtime/**/*
+
+R-loom-time-driver:
+- 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/**
+
+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/**
+
+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/**

.github/workflows/audit.yml

@@ -13,18 +13,12 @@ permissions:
   contents: read
 
 jobs:
-  security-audit:
+  cargo-deny:
     permissions:
-      checks: write  # for rustsec/audit-check to create check
-      contents: read  # for actions/checkout to fetch code
-      issues: write  # for rustsec/audit-check to create issues
+      checks: write
+      contents: read
+      issues: write
     runs-on: ubuntu-latest
-    if: "!contains(github.event.head_commit.message, 'ci skip')"
     steps:
-      - uses: actions/checkout@v3
-
-      - name: Audit Check
-        # https://github.com/rustsec/audit-check/issues/2
-        uses: rustsec/audit-check@master
-        with:
-          token: ${{ secrets.GITHUB_TOKEN }}
+    - uses: actions/checkout@v4
+    - uses: EmbarkStudios/cargo-deny-action@v2

.github/workflows/labeler.yml

@@ -4,6 +4,10 @@ on:
 
 # See .github/labeler.yml file
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.sha }}
+  cancel-in-progress: true
+
 permissions:
   contents: read
 

.github/workflows/loom.yml

@@ -7,8 +7,14 @@ on:
 
 name: Loom
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.sha }}
+  cancel-in-progress: true
+
 env:
-  RUSTFLAGS: -Dwarnings
+  RUSTFLAGS: -Dwarnings --cfg loom --cfg tokio_unstable -C debug_assertions
+  LOOM_MAX_PREEMPTIONS: 2
+  LOOM_MAX_BRANCHES: 10000
   RUST_BACKTRACE: 1
   # Change to specific Rust release to pin
   rust_stable: stable
@@ -17,32 +23,100 @@ permissions:
   contents: read
 
 jobs:
-  loom:
-    name: loom
+  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') || (github.base_ref == null))
+    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
+      - 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 sync::tests
+        working-directory: tokio
+
+  loom-time-driver:
+    name: loom time driver
+    # 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-time-driver') || (github.base_ref == null))
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - 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
+        working-directory: tokio
+
+  loom-current-thread:
+    name: loom current-thread scheduler
+    # 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-current-thread') || (github.base_ref == null))
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - 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_current_thread
+        working-directory: tokio
+
+  loom-multi-thread:
+    name: loom multi-thread scheduler
+    # 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') || (github.base_ref == null))
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        scope:
-          - --skip loom_pool
-          - loom_pool::group_a
-          - loom_pool::group_b
-          - loom_pool::group_c
-          - loom_pool::group_d
-          - time::driver
+        include:
+          - scope: loom_multi_thread::group_a
+          - scope: loom_multi_thread::group_b
+          - scope: loom_multi_thread::group_c
+          - scope: loom_multi_thread::group_d
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - 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
+        run: cargo test --lib --release --features full -- $SCOPE
+        working-directory: tokio
+        env:
+          SCOPE: ${{ matrix.scope }}
+
+  loom-multi-thread-alt:
+    name: loom ALT multi-thread scheduler
+    # 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))
+    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
+      - 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 -- $SCOPE
         working-directory: tokio
         env:
-          RUSTFLAGS: --cfg loom --cfg tokio_unstable -Dwarnings
-          LOOM_MAX_PREEMPTIONS: 2
-          LOOM_MAX_BRANCHES: 10000
           SCOPE: ${{ matrix.scope }}

.github/workflows/pr-audit.yml

@@ -8,21 +8,16 @@ on:
     paths:
       - '**/Cargo.toml'
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.sha }}
+  cancel-in-progress: true
+
 permissions:
   contents: read
 
 jobs:
-  security-audit:
+  cargo-deny:
     runs-on: ubuntu-latest
-    if: "!contains(github.event.head_commit.message, 'ci skip')"
     steps:
-      - uses: actions/checkout@v3
-
-      - name: Install cargo-audit
-        run: cargo install cargo-audit
-
-      - name: Generate lockfile
-        run: cargo generate-lockfile
-
-      - name: Audit dependencies
-        run: cargo audit
+    - uses: actions/checkout@v4
+    - uses: EmbarkStudios/cargo-deny-action@v2

.github/workflows/stress-test.yml

@@ -5,11 +5,15 @@ on:
     branches:
       - master
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.sha }}
+  cancel-in-progress: true
+
 env:
   RUSTFLAGS: -Dwarnings
   RUST_BACKTRACE: 1
   # Change to specific Rust release to pin
-  rust_stable: stable
+  rust_stable: 1.82
 
 permissions:
   contents: read
@@ -23,19 +27,19 @@ jobs:
         stress-test:
           - simple_echo_tcp
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Install Rust ${{ env.rust_stable }}
         uses: dtolnay/rust-toolchain@master
         with:
             toolchain: ${{ env.rust_stable }}
-      - uses: Swatinem/rust-cache@v2
       - name: Install Valgrind
         uses: taiki-e/install-action@valgrind
 
+      - uses: Swatinem/rust-cache@v2
       # Compiles each of the stress test examples.
       - name: Compile stress test examples
         run: cargo build -p stress-test --release --example ${{ matrix.stress-test }}
 
       # Runs each of the examples using Valgrind. Detects leaks and displays them.
       - name: Run valgrind
-        run: valgrind --error-exitcode=1 --leak-check=full --show-leak-kinds=all ./target/release/examples/${{ matrix.stress-test }}
+        run: valgrind --error-exitcode=1 --leak-check=full --show-leak-kinds=all --fair-sched=yes ./target/release/examples/${{ matrix.stress-test }}

.gitignore

@@ -2,3 +2,4 @@ target
 Cargo.lock
 
 .cargo/config.toml
+.cargo/config

CONTRIBUTING.md

@@ -131,8 +131,11 @@ cargo check --all-features
 cargo test --all-features
 ```
 
-Clippy must be run using the MSRV, so Tokio can avoid having to `#[allow]` new
-lints whose fixes would be incompatible with the current MSRV:
+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:
@@ -146,23 +149,31 @@ When updating this, also update:
 -->
 
 ```
-cargo +1.49.0 clippy --all --tests --all-features
+cargo +1.77 clippy --all --tests --all-features
 ```
 
-When building documentation normally, the markers that list the features
-required for various parts of Tokio are missing. To build the documentation
-correctly, use this command:
+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" RUSTFLAGS="--cfg docsrs" cargo +nightly doc --all-features
+RUSTDOCFLAGS="--cfg docsrs --cfg tokio_unstable" RUSTFLAGS="--cfg docsrs --cfg tokio_unstable" cargo +nightly doc --all-features [--open]
 ```
 
-To build documentation including Tokio's unstable features, it is necessary to
-pass `--cfg tokio_unstable` to both RustDoc *and* rustc. To build the
-documentation for unstable features, use this command:
+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
 
 ```
-RUSTDOCFLAGS="--cfg docsrs --cfg tokio_unstable" RUSTFLAGS="--cfg docsrs --cfg tokio_unstable" cargo +nightly doc --all-features
+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
@@ -170,10 +181,10 @@ command below instead:
 
 ```
 # Mac or Linux
-rustfmt --check --edition 2018 $(git ls-files '*.rs')
+rustfmt --check --edition 2021 $(git ls-files '*.rs')
 
 # Powershell
-Get-ChildItem . -Filter "*.rs" -Recurse | foreach { rustfmt --check --edition 2018 $_.FullName }
+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.
@@ -181,24 +192,58 @@ it, `rustfmt` will update your files locally instead.
 You can run loom tests with
 ```
 cd tokio # tokio crate in workspace
-LOOM_MAX_PREEMPTIONS=1 RUSTFLAGS="--cfg loom" \
+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-tag-raw-pointers" \
-    cargo +nightly miri test --features full --lib
+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 and documentation tests
-(Tokio avoids unit tests as much as possible).
+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
 
@@ -213,10 +258,10 @@ integration tests in the crate and follow the style.
 
 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 
+To get started with fuzz testing you'll need to install
 [cargo-fuzz](https://github.com/rust-fuzz/cargo-fuzz).
 
-`cargo install cargo-fuzz`
+`cargo install --locked cargo-fuzz`
 
 To list the available fuzzing harnesses you can run;
 
@@ -224,7 +269,7 @@ To list the available fuzzing harnesses you can run;
 $ cd tokio
 $ cargo fuzz list
 fuzz_linked_list
-````
+```
 
 Running a fuzz test is as simple as;
 
@@ -310,6 +355,29 @@ example would explicitly use `Timeout::new`. For example:
 /// # }
 ```
 
+### 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
@@ -333,14 +401,16 @@ A good commit message should describe what changed and why.
     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
-  * be prefixed with the name of the sub crate being changed (without the `tokio-`
-    prefix) and start with an imperative verb. If modifying `tokio` proper,
-    omit the crate prefix.
+  * 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:
 
-  * timer: introduce `Timeout` and deprecate `Deadline`
-  * export `Encoder`, `Decoder`, `Framed*` from tokio_codec
+  * 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).
@@ -357,7 +427,7 @@ A good commit message should describe what changed and why.
 Sample complete commit message:
 
 ```txt
-subcrate: explain the commit in one line
+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
@@ -658,3 +728,7 @@ When releasing a new version of a crate, follow these steps:
    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

@@ -1,5 +1,5 @@
 [workspace]
-
+resolver = "2"
 members = [
   "tokio",
   "tokio-macros",
@@ -14,3 +14,19 @@ members = [
   "tests-build",
   "tests-integration",
 ]
+
+[workspace.metadata.spellcheck]
+config = "spellcheck.toml"
+
+[workspace.lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = [
+  'cfg(fuzzing)',
+  'cfg(loom)',
+  'cfg(mio_unsupported_force_poll_poll)',
+  'cfg(tokio_allow_from_blocking_fd)',
+  'cfg(tokio_internal_mt_counters)',
+  'cfg(tokio_no_parking_lot)',
+  'cfg(tokio_no_tuning_tests)',
+  'cfg(tokio_taskdump)',
+  'cfg(tokio_unstable)',
+] }

LICENSE

@@ -1,25 +1,21 @@
-Copyright (c) 2023 Tokio Contributors
+MIT License
 
-Permission is hereby granted, free of charge, to any
-person obtaining a copy of this software and associated
-documentation files (the "Software"), to deal in the
-Software without restriction, including without
-limitation the rights to use, copy, modify, merge,
-publish, distribute, sublicense, and/or sell copies of
-the Software, and to permit persons to whom the Software
-is furnished to do so, subject to the following
-conditions:
+Copyright (c) Tokio Contributors
 
-The above copyright notice and this permission notice
-shall be included in all copies or substantial portions
-of the Software.
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
 
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
-ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
-TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
-PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
-SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
-OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
-IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-DEALINGS IN THE SOFTWARE.
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -56,7 +56,7 @@ Make sure you activated the full features of the tokio crate on Cargo.toml:
 
 ```toml
 [dependencies]
-tokio = { version = "1.25.0", features = ["full"] }
+tokio = { version = "1.43.3", features = ["full"] }
 ```
 Then, on your main.rs:
 
@@ -78,7 +78,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
             loop {
                 let n = match socket.read(&mut buf).await {
                     // socket closed
-                    Ok(n) if n == 0 => return,
+                    Ok(0) => return,
                     Ok(n) => n,
                     Err(e) => {
                         eprintln!("failed to read from socket; err = {:?}", e);
@@ -132,6 +132,8 @@ project.
 In addition to the crates in this repository, the Tokio project also maintains
 several other libraries, including:
 
+* [`axum`]: A web application framework that focuses on ergonomics and modularity.
+
 * [`hyper`]: A fast and correct HTTP/1.1 and HTTP/2 implementation for Rust.
 
 * [`tonic`]: A gRPC over HTTP/2 implementation focused on high performance, interoperability, and flexibility.
@@ -142,21 +144,18 @@ several other libraries, including:
 
 * [`tracing`] (formerly `tokio-trace`): A framework for application-level tracing and async-aware diagnostics.
 
-* [`rdbc`]: A Rust database connectivity library for MySQL, Postgres and SQLite.
-
-* [`mio`]: A low-level, cross-platform abstraction over OS I/O APIs that powers
-  `tokio`.
+* [`mio`]: A low-level, cross-platform abstraction over OS I/O APIs that powers `tokio`.
 
 * [`bytes`]: Utilities for working with bytes, including efficient byte buffers.
 
-* [`loom`]: A testing tool for concurrent Rust code
+* [`loom`]: A testing tool for concurrent Rust code.
 
+[`axum`]: https://github.com/tokio-rs/axum
 [`warp`]: https://github.com/seanmonstar/warp
 [`hyper`]: https://github.com/hyperium/hyper
 [`tonic`]: https://github.com/hyperium/tonic
 [`tower`]: https://github.com/tower-rs/tower
 [`loom`]: https://github.com/tokio-rs/loom
-[`rdbc`]: https://github.com/tokio-rs/rdbc
 [`tracing`]: https://github.com/tokio-rs/tracing
 [`mio`]: https://github.com/tokio-rs/mio
 [`bytes`]: https://github.com/tokio-rs/bytes
@@ -187,7 +186,22 @@ 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 1.49.0.
+released at least six months ago. The current MSRV is 1.70.
+
+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
+ * 1.30 to 1.38 - Rust 1.63
+ * 1.27 to 1.29 - Rust 1.56
+ * 1.17 to 1.26 - Rust 1.49
+ * 1.15 to 1.16 - Rust 1.46
+ * 1.0 to 1.14 - Rust 1.45
+
+Note that although we try to avoid the situation where a dependency transitively
+increases the MSRV of Tokio, we do not guarantee that this does not happen.
+However, every minor release will have some set of versions of dependencies that
+works with the MSRV of that minor release.
 
 ## Release schedule
 
@@ -202,20 +216,29 @@ 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:
 
- * `1.18.x` - LTS release until June 2023
- * `1.20.x` - LTS release until September 2023.
+ * `1.36.x` - LTS release until March 2025. (MSRV 1.63)
+ * `1.38.x` - LTS release until July 2025. (MSRV 1.63)
 
 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 `1.18.x` patch release, you
+example, to specify that you wish to use the newest `1.32.x` patch release, you
 can use the following dependency specification:
 ```text
-tokio = { version = "~1.18", features = [...] }
+tokio = { version = "~1.32", features = [...] }
 ```
 
+### Previous LTS releases
+
+ * `1.8.x` - LTS release until February 2022.
+ * `1.14.x` - LTS release until June 2022.
+ * `1.18.x` - LTS release until June 2023.
+ * `1.20.x` - LTS release until September 2023.
+ * `1.25.x` - LTS release until March 2024.
+ * `1.32.x` - LTS release until September 2024.
+
 ## License
 
 This project is licensed under the [MIT license].

benches/Cargo.toml

@@ -2,17 +2,21 @@
 name = "benches"
 version = "0.0.0"
 publish = false
-edition = "2018"
+edition = "2021"
+license = "MIT"
+
+[features]
+test-util = ["tokio/test-util"]
 
 [dependencies]
 tokio = { version = "1.5.0", path = "../tokio", features = ["full"] }
-bencher = "0.1.5"
+criterion = "0.5.1"
 rand = "0.8"
 rand_chacha = "0.3"
 
 [dev-dependencies]
 tokio-util = { version = "0.7.0", path = "../tokio-util", features = ["full"] }
-tokio-stream = { path = "../tokio-stream" }
+tokio-stream = { version = "0.1", path = "../tokio-stream" }
 
 [target.'cfg(unix)'.dependencies]
 libc = "0.2.42"
@@ -22,6 +26,11 @@ name = "spawn"
 path = "spawn.rs"
 harness = false
 
+[[bench]]
+name = "sync_broadcast"
+path = "sync_broadcast.rs"
+harness = false
+
 [[bench]]
 name = "sync_mpsc"
 path = "sync_mpsc.rs"
@@ -37,11 +46,20 @@ name = "sync_watch"
 path = "sync_watch.rs"
 harness = false
 
+[[bench]]
+name = "rt_current_thread"
+path = "rt_current_thread.rs"
+harness = false
+
 [[bench]]
 name = "rt_multi_threaded"
 path = "rt_multi_threaded.rs"
 harness = false
 
+[[bench]]
+name = "sync_notify"
+path = "sync_notify.rs"
+harness = false
 
 [[bench]]
 name = "sync_rwlock"
@@ -67,3 +85,13 @@ harness = false
 name = "copy"
 path = "copy.rs"
 harness = false
+
+[[bench]]
+name = "time_now"
+path = "time_now.rs"
+harness = false
+
+[[bench]]
+name = "time_timeout"
+path = "time_timeout.rs"
+harness = false

benches/copy.rs

@@ -1,4 +1,4 @@
-use bencher::{benchmark_group, benchmark_main, Bencher};
+use criterion::{criterion_group, criterion_main, Criterion};
 
 use rand::{Rng, SeedableRng};
 use rand_chacha::ChaCha20Rng;
@@ -29,7 +29,7 @@ const WRITE_SERVICE_PERIOD: Duration = Duration::from_millis(20);
 // because another writer claimed the buffer space
 const PROBABILITY_FLUSH_WAIT: f64 = 0.1;
 
-/// A slow writer that aims to simulate HDD behaviour under heavy load.
+/// A slow writer that aims to simulate HDD behavior under heavy load.
 ///
 /// There is a limited buffer, which is fully drained on the next write after
 /// a time limit is reached. Flush waits for the time limit to be reached
@@ -64,7 +64,7 @@ impl SlowHddWriter {
     ) -> std::task::Poll<Result<(), std::io::Error>> {
         // If we hit a service interval, the buffer can be cleared
         let res = self.service_intervals.poll_tick(cx).map(|_| Ok(()));
-        if let Poll::Ready(_) = res {
+        if res.is_ready() {
             self.buffer_used = 0;
         }
         res
@@ -123,7 +123,7 @@ impl AsyncWrite for SlowHddWriter {
         cx: &mut std::task::Context<'_>,
         bufs: &[std::io::IoSlice<'_>],
     ) -> std::task::Poll<Result<usize, std::io::Error>> {
-        let writeable = bufs.into_iter().fold(0, |acc, buf| acc + buf.len());
+        let writeable = bufs.iter().fold(0, |acc, buf| acc + buf.len());
         self.write_bytes(cx, writeable)
     }
 
@@ -174,65 +174,77 @@ fn rt() -> tokio::runtime::Runtime {
         .unwrap()
 }
 
-fn copy_mem_to_mem(b: &mut Bencher) {
+fn copy_mem_to_mem(c: &mut Criterion) {
     let rt = rt();
 
-    b.iter(|| {
-        let task = || async {
-            let mut source = repeat(0).take(SOURCE_SIZE);
-            let mut dest = Vec::new();
-            copy(&mut source, &mut dest).await.unwrap();
-        };
+    c.bench_function("copy_mem_to_mem", |b| {
+        b.iter(|| {
+            let task = || async {
+                let mut source = repeat(0).take(SOURCE_SIZE);
+                let mut dest = Vec::new();
+                copy(&mut source, &mut dest).await.unwrap();
+            };
 
-        rt.block_on(task());
-    })
+            rt.block_on(task());
+        })
+    });
 }
 
-fn copy_mem_to_slow_hdd(b: &mut Bencher) {
+fn copy_mem_to_slow_hdd(c: &mut Criterion) {
     let rt = rt();
 
-    b.iter(|| {
-        let task = || async {
-            let mut source = repeat(0).take(SOURCE_SIZE);
-            let mut dest = SlowHddWriter::new(WRITE_SERVICE_PERIOD, WRITE_BUFFER);
-            copy(&mut source, &mut dest).await.unwrap();
-        };
+    c.bench_function("copy_mem_to_slow_hdd", |b| {
+        b.iter(|| {
+            let task = || async {
+                let mut source = repeat(0).take(SOURCE_SIZE);
+                let mut dest = SlowHddWriter::new(WRITE_SERVICE_PERIOD, WRITE_BUFFER);
+                copy(&mut source, &mut dest).await.unwrap();
+            };
 
-        rt.block_on(task());
-    })
+            rt.block_on(task());
+        })
+    });
 }
 
-fn copy_chunk_to_mem(b: &mut Bencher) {
+fn copy_chunk_to_mem(c: &mut Criterion) {
     let rt = rt();
-    b.iter(|| {
-        let task = || async {
-            let mut source = ChunkReader::new(CHUNK_SIZE, READ_SERVICE_PERIOD).take(SOURCE_SIZE);
-            let mut dest = Vec::new();
-            copy(&mut source, &mut dest).await.unwrap();
-        };
 
-        rt.block_on(task());
-    })
+    c.bench_function("copy_chunk_to_mem", |b| {
+        b.iter(|| {
+            let task = || async {
+                let mut source =
+                    ChunkReader::new(CHUNK_SIZE, READ_SERVICE_PERIOD).take(SOURCE_SIZE);
+                let mut dest = Vec::new();
+                copy(&mut source, &mut dest).await.unwrap();
+            };
+
+            rt.block_on(task());
+        })
+    });
 }
 
-fn copy_chunk_to_slow_hdd(b: &mut Bencher) {
+fn copy_chunk_to_slow_hdd(c: &mut Criterion) {
     let rt = rt();
-    b.iter(|| {
-        let task = || async {
-            let mut source = ChunkReader::new(CHUNK_SIZE, READ_SERVICE_PERIOD).take(SOURCE_SIZE);
-            let mut dest = SlowHddWriter::new(WRITE_SERVICE_PERIOD, WRITE_BUFFER);
-            copy(&mut source, &mut dest).await.unwrap();
-        };
 
-        rt.block_on(task());
-    })
+    c.bench_function("copy_chunk_to_slow_hdd", |b| {
+        b.iter(|| {
+            let task = || async {
+                let mut source =
+                    ChunkReader::new(CHUNK_SIZE, READ_SERVICE_PERIOD).take(SOURCE_SIZE);
+                let mut dest = SlowHddWriter::new(WRITE_SERVICE_PERIOD, WRITE_BUFFER);
+                copy(&mut source, &mut dest).await.unwrap();
+            };
+
+            rt.block_on(task());
+        })
+    });
 }
 
-benchmark_group!(
+criterion_group!(
     copy_bench,
     copy_mem_to_mem,
     copy_mem_to_slow_hdd,
     copy_chunk_to_mem,
     copy_chunk_to_slow_hdd,
 );
-benchmark_main!(copy_bench);
+criterion_main!(copy_bench);

benches/fs.rs

@@ -6,7 +6,7 @@ use tokio::fs::File;
 use tokio::io::AsyncReadExt;
 use tokio_util::codec::{BytesCodec, FramedRead /*FramedWrite*/};
 
-use bencher::{benchmark_group, benchmark_main, Bencher};
+use criterion::{criterion_group, criterion_main, Criterion};
 
 use std::fs::File as StdFile;
 use std::io::Read as StdRead;
@@ -23,81 +23,90 @@ const BLOCK_COUNT: usize = 1_000;
 const BUFFER_SIZE: usize = 4096;
 const DEV_ZERO: &str = "/dev/zero";
 
-fn async_read_codec(b: &mut Bencher) {
+fn async_read_codec(c: &mut Criterion) {
     let rt = rt();
 
-    b.iter(|| {
-        let task = || async {
-            let file = File::open(DEV_ZERO).await.unwrap();
-            let mut input_stream = FramedRead::with_capacity(file, BytesCodec::new(), BUFFER_SIZE);
+    c.bench_function("async_read_codec", |b| {
+        b.iter(|| {
+            let task = || async {
+                let file = File::open(DEV_ZERO).await.unwrap();
+                let mut input_stream =
+                    FramedRead::with_capacity(file, BytesCodec::new(), BUFFER_SIZE);
 
-            for _i in 0..BLOCK_COUNT {
-                let _bytes = input_stream.next().await.unwrap();
-            }
-        };
-
-        rt.block_on(task());
-    });
-}
-
-fn async_read_buf(b: &mut Bencher) {
-    let rt = rt();
-
-    b.iter(|| {
-        let task = || async {
-            let mut file = File::open(DEV_ZERO).await.unwrap();
-            let mut buffer = [0u8; BUFFER_SIZE];
-
-            for _i in 0..BLOCK_COUNT {
-                let count = file.read(&mut buffer).await.unwrap();
-                if count == 0 {
-                    break;
+                for _i in 0..BLOCK_COUNT {
+                    let _bytes = input_stream.next().await.unwrap();
                 }
-            }
-        };
+            };
 
-        rt.block_on(task());
+            rt.block_on(task());
+        })
     });
 }
 
-fn async_read_std_file(b: &mut Bencher) {
+fn async_read_buf(c: &mut Criterion) {
     let rt = rt();
 
-    let task = || async {
-        let mut file = tokio::task::block_in_place(|| Box::pin(StdFile::open(DEV_ZERO).unwrap()));
+    c.bench_function("async_read_buf", |b| {
+        b.iter(|| {
+            let task = || async {
+                let mut file = File::open(DEV_ZERO).await.unwrap();
+                let mut buffer = [0u8; BUFFER_SIZE];
 
-        for _i in 0..BLOCK_COUNT {
+                for _i in 0..BLOCK_COUNT {
+                    let count = file.read(&mut buffer).await.unwrap();
+                    if count == 0 {
+                        break;
+                    }
+                }
+            };
+
+            rt.block_on(task());
+        });
+    });
+}
+
+fn async_read_std_file(c: &mut Criterion) {
+    let rt = rt();
+
+    c.bench_function("async_read_std_file", |b| {
+        b.iter(|| {
+            let task = || async {
+                let mut file =
+                    tokio::task::block_in_place(|| Box::pin(StdFile::open(DEV_ZERO).unwrap()));
+
+                for _i in 0..BLOCK_COUNT {
+                    let mut buffer = [0u8; BUFFER_SIZE];
+                    let mut file_ref = file.as_mut();
+
+                    tokio::task::block_in_place(move || {
+                        file_ref.read_exact(&mut buffer).unwrap();
+                    });
+                }
+            };
+
+            rt.block_on(task());
+        });
+    });
+}
+
+fn sync_read(c: &mut Criterion) {
+    c.bench_function("sync_read", |b| {
+        b.iter(|| {
+            let mut file = StdFile::open(DEV_ZERO).unwrap();
             let mut buffer = [0u8; BUFFER_SIZE];
-            let mut file_ref = file.as_mut();
 
-            tokio::task::block_in_place(move || {
-                file_ref.read_exact(&mut buffer).unwrap();
-            });
-        }
-    };
-
-    b.iter(|| {
-        rt.block_on(task());
+            for _i in 0..BLOCK_COUNT {
+                file.read_exact(&mut buffer).unwrap();
+            }
+        })
     });
 }
 
-fn sync_read(b: &mut Bencher) {
-    b.iter(|| {
-        let mut file = StdFile::open(DEV_ZERO).unwrap();
-        let mut buffer = [0u8; BUFFER_SIZE];
-
-        for _i in 0..BLOCK_COUNT {
-            file.read_exact(&mut buffer).unwrap();
-        }
-    });
-}
-
-benchmark_group!(
+criterion_group!(
     file,
     async_read_std_file,
     async_read_buf,
     async_read_codec,
     sync_read
 );
-
-benchmark_main!(file);
+criterion_main!(file);

benches/rt_current_thread.rs

@@ -0,0 +1,89 @@
+//! Benchmark implementation details of the threaded scheduler. These benches are
+//! intended to be used as a form of regression testing and not as a general
+//! purpose benchmark demonstrating real-world performance.
+
+use tokio::runtime::{self, Runtime};
+
+use criterion::{criterion_group, criterion_main, Criterion};
+
+const NUM_SPAWN: usize = 1_000;
+
+fn rt_curr_spawn_many_local(c: &mut Criterion) {
+    let rt = rt();
+    let mut handles = Vec::with_capacity(NUM_SPAWN);
+
+    c.bench_function("spawn_many_local", |b| {
+        b.iter(|| {
+            rt.block_on(async {
+                for _ in 0..NUM_SPAWN {
+                    handles.push(tokio::spawn(async move {}));
+                }
+
+                for handle in handles.drain(..) {
+                    handle.await.unwrap();
+                }
+            });
+        })
+    });
+}
+
+fn rt_curr_spawn_many_remote_idle(c: &mut Criterion) {
+    let rt = rt();
+    let rt_handle = rt.handle();
+    let mut handles = Vec::with_capacity(NUM_SPAWN);
+
+    c.bench_function("spawn_many_remote_idle", |b| {
+        b.iter(|| {
+            for _ in 0..NUM_SPAWN {
+                handles.push(rt_handle.spawn(async {}));
+            }
+
+            rt.block_on(async {
+                for handle in handles.drain(..) {
+                    handle.await.unwrap();
+                }
+            });
+        })
+    });
+}
+
+fn rt_curr_spawn_many_remote_busy(c: &mut Criterion) {
+    let rt = rt();
+    let rt_handle = rt.handle();
+    let mut handles = Vec::with_capacity(NUM_SPAWN);
+
+    rt.spawn(async {
+        fn iter() {
+            tokio::spawn(async { iter() });
+        }
+
+        iter()
+    });
+
+    c.bench_function("spawn_many_remote_busy", |b| {
+        b.iter(|| {
+            for _ in 0..NUM_SPAWN {
+                handles.push(rt_handle.spawn(async {}));
+            }
+
+            rt.block_on(async {
+                for handle in handles.drain(..) {
+                    handle.await.unwrap();
+                }
+            });
+        })
+    });
+}
+
+fn rt() -> Runtime {
+    runtime::Builder::new_current_thread().build().unwrap()
+}
+
+criterion_group!(
+    rt_curr_scheduler,
+    rt_curr_spawn_many_local,
+    rt_curr_spawn_many_remote_idle,
+    rt_curr_spawn_many_remote_busy
+);
+
+criterion_main!(rt_curr_scheduler);

benches/rt_multi_threaded.rs

@@ -5,67 +5,173 @@
 use tokio::runtime::{self, Runtime};
 use tokio::sync::oneshot;
 
-use bencher::{benchmark_group, benchmark_main, Bencher};
-use std::sync::atomic::AtomicUsize;
 use std::sync::atomic::Ordering::Relaxed;
+use std::sync::atomic::{AtomicBool, AtomicUsize};
 use std::sync::{mpsc, Arc};
+use std::time::{Duration, Instant};
 
-fn spawn_many(b: &mut Bencher) {
-    const NUM_SPAWN: usize = 10_000;
+use criterion::{criterion_group, criterion_main, Criterion};
 
+const NUM_WORKERS: usize = 4;
+const NUM_SPAWN: usize = 10_000;
+const STALL_DUR: Duration = Duration::from_micros(10);
+
+fn rt_multi_spawn_many_local(c: &mut Criterion) {
     let rt = rt();
 
     let (tx, rx) = mpsc::sync_channel(1000);
     let rem = Arc::new(AtomicUsize::new(0));
 
-    b.iter(|| {
-        rem.store(NUM_SPAWN, Relaxed);
+    c.bench_function("spawn_many_local", |b| {
+        b.iter(|| {
+            rem.store(NUM_SPAWN, Relaxed);
 
-        rt.block_on(async {
-            for _ in 0..NUM_SPAWN {
-                let tx = tx.clone();
-                let rem = rem.clone();
+            rt.block_on(async {
+                for _ in 0..NUM_SPAWN {
+                    let tx = tx.clone();
+                    let rem = rem.clone();
 
-                tokio::spawn(async move {
-                    if 1 == rem.fetch_sub(1, Relaxed) {
-                        tx.send(()).unwrap();
-                    }
-                });
-            }
+                    tokio::spawn(async move {
+                        if 1 == rem.fetch_sub(1, Relaxed) {
+                            tx.send(()).unwrap();
+                        }
+                    });
+                }
 
-            let _ = rx.recv().unwrap();
-        });
+                rx.recv().unwrap();
+            });
+        })
     });
 }
 
-fn yield_many(b: &mut Bencher) {
+fn rt_multi_spawn_many_remote_idle(c: &mut Criterion) {
+    let rt = rt();
+
+    let mut handles = Vec::with_capacity(NUM_SPAWN);
+
+    c.bench_function("spawn_many_remote_idle", |b| {
+        b.iter(|| {
+            for _ in 0..NUM_SPAWN {
+                handles.push(rt.spawn(async {}));
+            }
+
+            rt.block_on(async {
+                for handle in handles.drain(..) {
+                    handle.await.unwrap();
+                }
+            });
+        })
+    });
+}
+
+// The runtime is busy with tasks that consume CPU time and yield. Yielding is a
+// lower notification priority than spawning / regular notification.
+fn rt_multi_spawn_many_remote_busy1(c: &mut Criterion) {
+    let rt = rt();
+    let rt_handle = rt.handle();
+    let mut handles = Vec::with_capacity(NUM_SPAWN);
+    let flag = Arc::new(AtomicBool::new(true));
+
+    // Spawn some tasks to keep the runtimes busy
+    for _ in 0..(2 * NUM_WORKERS) {
+        let flag = flag.clone();
+        rt.spawn(async move {
+            while flag.load(Relaxed) {
+                tokio::task::yield_now().await;
+                stall();
+            }
+        });
+    }
+
+    c.bench_function("spawn_many_remote_busy1", |b| {
+        b.iter(|| {
+            for _ in 0..NUM_SPAWN {
+                handles.push(rt_handle.spawn(async {}));
+            }
+
+            rt.block_on(async {
+                for handle in handles.drain(..) {
+                    handle.await.unwrap();
+                }
+            });
+        })
+    });
+
+    flag.store(false, Relaxed);
+}
+
+// The runtime is busy with tasks that consume CPU time and spawn new high-CPU
+// tasks. Spawning goes via a higher notification priority than yielding.
+fn rt_multi_spawn_many_remote_busy2(c: &mut Criterion) {
+    const NUM_SPAWN: usize = 1_000;
+
+    let rt = rt();
+    let rt_handle = rt.handle();
+    let mut handles = Vec::with_capacity(NUM_SPAWN);
+    let flag = Arc::new(AtomicBool::new(true));
+
+    // Spawn some tasks to keep the runtimes busy
+    for _ in 0..(NUM_WORKERS) {
+        let flag = flag.clone();
+        fn iter(flag: Arc<AtomicBool>) {
+            tokio::spawn(async {
+                if flag.load(Relaxed) {
+                    stall();
+                    iter(flag);
+                }
+            });
+        }
+        rt.spawn(async {
+            iter(flag);
+        });
+    }
+
+    c.bench_function("spawn_many_remote_busy2", |b| {
+        b.iter(|| {
+            for _ in 0..NUM_SPAWN {
+                handles.push(rt_handle.spawn(async {}));
+            }
+
+            rt.block_on(async {
+                for handle in handles.drain(..) {
+                    handle.await.unwrap();
+                }
+            });
+        })
+    });
+
+    flag.store(false, Relaxed);
+}
+
+fn rt_multi_yield_many(c: &mut Criterion) {
     const NUM_YIELD: usize = 1_000;
     const TASKS: usize = 200;
 
-    let rt = rt();
+    c.bench_function("yield_many", |b| {
+        let rt = rt();
+        let (tx, rx) = mpsc::sync_channel(TASKS);
 
-    let (tx, rx) = mpsc::sync_channel(TASKS);
+        b.iter(move || {
+            for _ in 0..TASKS {
+                let tx = tx.clone();
 
-    b.iter(move || {
-        for _ in 0..TASKS {
-            let tx = tx.clone();
+                rt.spawn(async move {
+                    for _ in 0..NUM_YIELD {
+                        tokio::task::yield_now().await;
+                    }
 
-            rt.spawn(async move {
-                for _ in 0..NUM_YIELD {
-                    tokio::task::yield_now().await;
-                }
+                    tx.send(()).unwrap();
+                });
+            }
 
-                tx.send(()).unwrap();
-            });
-        }
-
-        for _ in 0..TASKS {
-            let _ = rx.recv().unwrap();
-        }
+            for _ in 0..TASKS {
+                rx.recv().unwrap();
+            }
+        })
     });
 }
 
-fn ping_pong(b: &mut Bencher) {
+fn rt_multi_ping_pong(c: &mut Criterion) {
     const NUM_PINGS: usize = 1_000;
 
     let rt = rt();
@@ -73,46 +179,46 @@ fn ping_pong(b: &mut Bencher) {
     let (done_tx, done_rx) = mpsc::sync_channel(1000);
     let rem = Arc::new(AtomicUsize::new(0));
 
-    b.iter(|| {
-        let done_tx = done_tx.clone();
-        let rem = rem.clone();
-        rem.store(NUM_PINGS, Relaxed);
+    c.bench_function("ping_pong", |b| {
+        b.iter(|| {
+            let done_tx = done_tx.clone();
+            let rem = rem.clone();
+            rem.store(NUM_PINGS, Relaxed);
 
-        rt.block_on(async {
-            tokio::spawn(async move {
-                for _ in 0..NUM_PINGS {
-                    let rem = rem.clone();
-                    let done_tx = done_tx.clone();
-
-                    tokio::spawn(async move {
-                        let (tx1, rx1) = oneshot::channel();
-                        let (tx2, rx2) = oneshot::channel();
+            rt.block_on(async {
+                tokio::spawn(async move {
+                    for _ in 0..NUM_PINGS {
+                        let rem = rem.clone();
+                        let done_tx = done_tx.clone();
 
                         tokio::spawn(async move {
-                            rx1.await.unwrap();
-                            tx2.send(()).unwrap();
+                            let (tx1, rx1) = oneshot::channel();
+                            let (tx2, rx2) = oneshot::channel();
+
+                            tokio::spawn(async move {
+                                rx1.await.unwrap();
+                                tx2.send(()).unwrap();
+                            });
+
+                            tx1.send(()).unwrap();
+                            rx2.await.unwrap();
+
+                            if 1 == rem.fetch_sub(1, Relaxed) {
+                                done_tx.send(()).unwrap();
+                            }
                         });
+                    }
+                });
 
-                        tx1.send(()).unwrap();
-                        rx2.await.unwrap();
-
-                        if 1 == rem.fetch_sub(1, Relaxed) {
-                            done_tx.send(()).unwrap();
-                        }
-                    });
-                }
+                done_rx.recv().unwrap();
             });
-
-            done_rx.recv().unwrap();
-        });
+        })
     });
 }
 
-fn chained_spawn(b: &mut Bencher) {
+fn rt_multi_chained_spawn(c: &mut Criterion) {
     const ITER: usize = 1_000;
 
-    let rt = rt();
-
     fn iter(done_tx: mpsc::SyncSender<()>, n: usize) {
         if n == 0 {
             done_tx.send(()).unwrap();
@@ -123,29 +229,48 @@ fn chained_spawn(b: &mut Bencher) {
         }
     }
 
-    let (done_tx, done_rx) = mpsc::sync_channel(1000);
+    c.bench_function("chained_spawn", |b| {
+        let rt = rt();
+        let (done_tx, done_rx) = mpsc::sync_channel(1000);
 
-    b.iter(move || {
-        let done_tx = done_tx.clone();
+        b.iter(move || {
+            let done_tx = done_tx.clone();
 
-        rt.block_on(async {
-            tokio::spawn(async move {
-                iter(done_tx, ITER);
+            rt.block_on(async {
+                tokio::spawn(async move {
+                    iter(done_tx, ITER);
+                });
+
+                done_rx.recv().unwrap();
             });
-
-            done_rx.recv().unwrap();
-        });
+        })
     });
 }
 
 fn rt() -> Runtime {
     runtime::Builder::new_multi_thread()
-        .worker_threads(4)
+        .worker_threads(NUM_WORKERS)
         .enable_all()
         .build()
         .unwrap()
 }
 
-benchmark_group!(scheduler, spawn_many, ping_pong, yield_many, chained_spawn,);
+fn stall() {
+    let now = Instant::now();
+    while now.elapsed() < STALL_DUR {
+        std::thread::yield_now();
+    }
+}
 
-benchmark_main!(scheduler);
+criterion_group!(
+    rt_multi_scheduler,
+    rt_multi_spawn_many_local,
+    rt_multi_spawn_many_remote_idle,
+    rt_multi_spawn_many_remote_busy1,
+    rt_multi_spawn_many_remote_busy2,
+    rt_multi_ping_pong,
+    rt_multi_yield_many,
+    rt_multi_chained_spawn,
+);
+
+criterion_main!(rt_multi_scheduler);

benches/signal.rs

@@ -1,7 +1,7 @@
 //! Benchmark the delay in propagating OS signals to any listeners.
 #![cfg(unix)]
 
-use bencher::{benchmark_group, benchmark_main, Bencher};
+use criterion::{criterion_group, criterion_main, Criterion};
 use std::future::Future;
 use std::pin::Pin;
 use std::task::{Context, Poll};
@@ -41,7 +41,7 @@ pub fn send_signal(signal: libc::c_int) {
     }
 }
 
-fn many_signals(bench: &mut Bencher) {
+fn many_signals(c: &mut Criterion) {
     let num_signals = 10;
     let (tx, mut rx) = mpsc::channel(num_signals);
 
@@ -75,21 +75,23 @@ fn many_signals(bench: &mut Bencher) {
     // tasks have been polled at least once
     rt.block_on(Spinner::new());
 
-    bench.iter(|| {
-        rt.block_on(async {
-            send_signal(libc::SIGCHLD);
-            for _ in 0..num_signals {
-                rx.recv().await.expect("channel closed");
-            }
+    c.bench_function("many_signals", |b| {
+        b.iter(|| {
+            rt.block_on(async {
+                send_signal(libc::SIGCHLD);
+                for _ in 0..num_signals {
+                    rx.recv().await.expect("channel closed");
+                }
 
-            send_signal(libc::SIGIO);
-            for _ in 0..num_signals {
-                rx.recv().await.expect("channel closed");
-            }
-        });
+                send_signal(libc::SIGIO);
+                for _ in 0..num_signals {
+                    rx.recv().await.expect("channel closed");
+                }
+            });
+        })
     });
 }
 
-benchmark_group!(signal_group, many_signals,);
+criterion_group!(signal_group, many_signals);
 
-benchmark_main!(signal_group);
+criterion_main!(signal_group);

benches/spawn.rs

@@ -2,10 +2,7 @@
 //! This essentially measure the time to enqueue a task in the local and remote
 //! case.
 
-#[macro_use]
-extern crate bencher;
-
-use bencher::{black_box, Bencher};
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
 
 async fn work() -> usize {
     let val = 1 + 1;
@@ -13,67 +10,77 @@ async fn work() -> usize {
     black_box(val)
 }
 
-fn basic_scheduler_spawn(bench: &mut Bencher) {
+fn basic_scheduler_spawn(c: &mut Criterion) {
     let runtime = tokio::runtime::Builder::new_current_thread()
         .build()
         .unwrap();
-    bench.iter(|| {
-        runtime.block_on(async {
-            let h = tokio::spawn(work());
-            assert_eq!(h.await.unwrap(), 2);
-        });
+
+    c.bench_function("basic_scheduler_spawn", |b| {
+        b.iter(|| {
+            runtime.block_on(async {
+                let h = tokio::spawn(work());
+                assert_eq!(h.await.unwrap(), 2);
+            });
+        })
     });
 }
 
-fn basic_scheduler_spawn10(bench: &mut Bencher) {
+fn basic_scheduler_spawn10(c: &mut Criterion) {
     let runtime = tokio::runtime::Builder::new_current_thread()
         .build()
         .unwrap();
-    bench.iter(|| {
-        runtime.block_on(async {
-            let mut handles = Vec::with_capacity(10);
-            for _ in 0..10 {
-                handles.push(tokio::spawn(work()));
-            }
-            for handle in handles {
-                assert_eq!(handle.await.unwrap(), 2);
-            }
-        });
+
+    c.bench_function("basic_scheduler_spawn10", |b| {
+        b.iter(|| {
+            runtime.block_on(async {
+                let mut handles = Vec::with_capacity(10);
+                for _ in 0..10 {
+                    handles.push(tokio::spawn(work()));
+                }
+                for handle in handles {
+                    assert_eq!(handle.await.unwrap(), 2);
+                }
+            });
+        })
     });
 }
 
-fn threaded_scheduler_spawn(bench: &mut Bencher) {
+fn threaded_scheduler_spawn(c: &mut Criterion) {
     let runtime = tokio::runtime::Builder::new_multi_thread()
         .worker_threads(1)
         .build()
         .unwrap();
-    bench.iter(|| {
-        runtime.block_on(async {
-            let h = tokio::spawn(work());
-            assert_eq!(h.await.unwrap(), 2);
-        });
+    c.bench_function("threaded_scheduler_spawn", |b| {
+        b.iter(|| {
+            runtime.block_on(async {
+                let h = tokio::spawn(work());
+                assert_eq!(h.await.unwrap(), 2);
+            });
+        })
     });
 }
 
-fn threaded_scheduler_spawn10(bench: &mut Bencher) {
+fn threaded_scheduler_spawn10(c: &mut Criterion) {
     let runtime = tokio::runtime::Builder::new_multi_thread()
         .worker_threads(1)
         .build()
         .unwrap();
-    bench.iter(|| {
-        runtime.block_on(async {
-            let mut handles = Vec::with_capacity(10);
-            for _ in 0..10 {
-                handles.push(tokio::spawn(work()));
-            }
-            for handle in handles {
-                assert_eq!(handle.await.unwrap(), 2);
-            }
-        });
+    c.bench_function("threaded_scheduler_spawn10", |b| {
+        b.iter(|| {
+            runtime.block_on(async {
+                let mut handles = Vec::with_capacity(10);
+                for _ in 0..10 {
+                    handles.push(tokio::spawn(work()));
+                }
+                for handle in handles {
+                    assert_eq!(handle.await.unwrap(), 2);
+                }
+            });
+        })
     });
 }
 
-bencher::benchmark_group!(
+criterion_group!(
     spawn,
     basic_scheduler_spawn,
     basic_scheduler_spawn10,
@@ -81,4 +88,4 @@ bencher::benchmark_group!(
     threaded_scheduler_spawn10,
 );
 
-bencher::benchmark_main!(spawn);
+criterion_main!(spawn);

benches/sync_broadcast.rs

@@ -0,0 +1,82 @@
+use rand::{Rng, RngCore, SeedableRng};
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::sync::Arc;
+use tokio::sync::{broadcast, Notify};
+
+use criterion::measurement::WallTime;
+use criterion::{black_box, criterion_group, criterion_main, BenchmarkGroup, Criterion};
+
+fn rt() -> tokio::runtime::Runtime {
+    tokio::runtime::Builder::new_multi_thread()
+        .worker_threads(6)
+        .build()
+        .unwrap()
+}
+
+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>());
+    }
+    message
+        .as_bytes()
+        .iter()
+        .map(|&c| c as u32)
+        .fold(0, u32::wrapping_add)
+}
+
+fn contention_impl<const N_TASKS: usize>(g: &mut BenchmarkGroup<WallTime>) {
+    let rt = rt();
+
+    let (tx, _rx) = broadcast::channel::<usize>(1000);
+    let wg = Arc::new((AtomicUsize::new(0), Notify::new()));
+
+    for n in 0..N_TASKS {
+        let wg = wg.clone();
+        let mut rx = tx.subscribe();
+        let mut rng = rand::rngs::StdRng::seed_from_u64(n as u64);
+        rt.spawn(async move {
+            while (rx.recv().await).is_ok() {
+                let r = do_work(&mut rng);
+                let _ = black_box(r);
+                if wg.0.fetch_sub(1, Ordering::Relaxed) == 1 {
+                    wg.1.notify_one();
+                }
+            }
+        });
+    }
+
+    const N_ITERS: usize = 100;
+
+    g.bench_function(N_TASKS.to_string(), |b| {
+        b.iter(|| {
+            rt.block_on({
+                let wg = wg.clone();
+                let tx = tx.clone();
+                async move {
+                    for i in 0..N_ITERS {
+                        assert_eq!(wg.0.fetch_add(N_TASKS, Ordering::Relaxed), 0);
+                        tx.send(i).unwrap();
+                        while wg.0.load(Ordering::Relaxed) > 0 {
+                            wg.1.notified().await;
+                        }
+                    }
+                }
+            })
+        })
+    });
+}
+
+fn bench_contention(c: &mut Criterion) {
+    let mut group = c.benchmark_group("contention");
+    contention_impl::<10>(&mut group);
+    contention_impl::<100>(&mut group);
+    contention_impl::<500>(&mut group);
+    contention_impl::<1000>(&mut group);
+    group.finish();
+}
+
+criterion_group!(contention, bench_contention);
+
+criterion_main!(contention);

benches/sync_mpsc.rs

@@ -1,8 +1,23 @@
-use bencher::{black_box, Bencher};
 use tokio::sync::mpsc;
 
-type Medium = [usize; 64];
-type Large = [Medium; 64];
+use criterion::measurement::WallTime;
+use criterion::{black_box, criterion_group, criterion_main, BenchmarkGroup, Criterion};
+
+#[derive(Debug, Copy, Clone)]
+struct Medium(#[allow(dead_code)] [usize; 64]);
+impl Default for Medium {
+    fn default() -> Self {
+        Medium([0; 64])
+    }
+}
+
+#[derive(Debug, Copy, Clone)]
+struct Large(#[allow(dead_code)] [Medium; 64]);
+impl Default for Large {
+    fn default() -> Self {
+        Large([Medium::default(); 64])
+    }
+}
 
 fn rt() -> tokio::runtime::Runtime {
     tokio::runtime::Builder::new_multi_thread()
@@ -11,169 +26,306 @@ fn rt() -> tokio::runtime::Runtime {
         .unwrap()
 }
 
-fn create_1_medium(b: &mut Bencher) {
-    b.iter(|| {
-        black_box(&mpsc::channel::<Medium>(1));
-    });
-}
-
-fn create_100_medium(b: &mut Bencher) {
-    b.iter(|| {
-        black_box(&mpsc::channel::<Medium>(100));
-    });
-}
-
-fn create_100_000_medium(b: &mut Bencher) {
-    b.iter(|| {
-        black_box(&mpsc::channel::<Medium>(100_000));
-    });
-}
-
-fn send_medium(b: &mut Bencher) {
-    let rt = rt();
-
-    b.iter(|| {
-        let (tx, mut rx) = mpsc::channel::<Medium>(1000);
-
-        let _ = rt.block_on(tx.send([0; 64]));
-
-        rt.block_on(rx.recv()).unwrap();
-    });
-}
-
-fn send_large(b: &mut Bencher) {
-    let rt = rt();
-
-    b.iter(|| {
-        let (tx, mut rx) = mpsc::channel::<Large>(1000);
-
-        let _ = rt.block_on(tx.send([[0; 64]; 64]));
-
-        rt.block_on(rx.recv()).unwrap();
-    });
-}
-
-fn contention_bounded(b: &mut Bencher) {
-    let rt = rt();
-
-    b.iter(|| {
-        rt.block_on(async move {
-            let (tx, mut rx) = mpsc::channel::<usize>(1_000_000);
-
-            for _ in 0..5 {
-                let tx = tx.clone();
-                tokio::spawn(async move {
-                    for i in 0..1000 {
-                        tx.send(i).await.unwrap();
-                    }
-                });
-            }
-
-            for _ in 0..1_000 * 5 {
-                let _ = rx.recv().await;
-            }
+fn create_medium<const SIZE: usize>(g: &mut BenchmarkGroup<WallTime>) {
+    g.bench_function(SIZE.to_string(), |b| {
+        b.iter(|| {
+            black_box(&mpsc::channel::<Medium>(SIZE));
         })
     });
 }
 
-fn contention_bounded_full(b: &mut Bencher) {
+fn send_data<T: Default, const SIZE: usize>(g: &mut BenchmarkGroup<WallTime>, prefix: &str) {
     let rt = rt();
 
-    b.iter(|| {
-        rt.block_on(async move {
-            let (tx, mut rx) = mpsc::channel::<usize>(100);
+    g.bench_function(format!("{prefix}_{SIZE}"), |b| {
+        b.iter(|| {
+            let (tx, mut rx) = mpsc::channel::<T>(SIZE);
 
-            for _ in 0..5 {
-                let tx = tx.clone();
-                tokio::spawn(async move {
-                    for i in 0..1000 {
-                        tx.send(i).await.unwrap();
-                    }
-                });
-            }
+            let _ = rt.block_on(tx.send(T::default()));
 
-            for _ in 0..1_000 * 5 {
-                let _ = rx.recv().await;
-            }
+            rt.block_on(rx.recv()).unwrap();
         })
     });
 }
 
-fn contention_unbounded(b: &mut Bencher) {
+fn contention_bounded(g: &mut BenchmarkGroup<WallTime>) {
     let rt = rt();
 
-    b.iter(|| {
-        rt.block_on(async move {
-            let (tx, mut rx) = mpsc::unbounded_channel::<usize>();
+    g.bench_function("bounded", |b| {
+        b.iter(|| {
+            rt.block_on(async move {
+                let (tx, mut rx) = mpsc::channel::<usize>(1_000_000);
 
-            for _ in 0..5 {
-                let tx = tx.clone();
-                tokio::spawn(async move {
-                    for i in 0..1000 {
-                        tx.send(i).unwrap();
-                    }
-                });
-            }
+                for _ in 0..5 {
+                    let tx = tx.clone();
+                    tokio::spawn(async move {
+                        for i in 0..1000 {
+                            tx.send(i).await.unwrap();
+                        }
+                    });
+                }
 
-            for _ in 0..1_000 * 5 {
-                let _ = rx.recv().await;
-            }
+                for _ in 0..1_000 * 5 {
+                    let _ = rx.recv().await;
+                }
+            })
         })
     });
 }
 
-fn uncontented_bounded(b: &mut Bencher) {
+fn contention_bounded_recv_many(g: &mut BenchmarkGroup<WallTime>) {
     let rt = rt();
 
-    b.iter(|| {
-        rt.block_on(async move {
-            let (tx, mut rx) = mpsc::channel::<usize>(1_000_000);
+    g.bench_function("bounded_recv_many", |b| {
+        b.iter(|| {
+            rt.block_on(async move {
+                let (tx, mut rx) = mpsc::channel::<usize>(1_000_000);
 
-            for i in 0..5000 {
-                tx.send(i).await.unwrap();
-            }
+                for _ in 0..5 {
+                    let tx = tx.clone();
+                    tokio::spawn(async move {
+                        for i in 0..1000 {
+                            tx.send(i).await.unwrap();
+                        }
+                    });
+                }
 
-            for _ in 0..5_000 {
-                let _ = rx.recv().await;
-            }
+                let mut buffer = Vec::<usize>::with_capacity(5_000);
+                let mut total = 0;
+                while total < 1_000 * 5 {
+                    total += rx.recv_many(&mut buffer, 5_000).await;
+                }
+            })
         })
     });
 }
 
-fn uncontented_unbounded(b: &mut Bencher) {
+fn contention_bounded_full(g: &mut BenchmarkGroup<WallTime>) {
     let rt = rt();
 
-    b.iter(|| {
-        rt.block_on(async move {
-            let (tx, mut rx) = mpsc::unbounded_channel::<usize>();
+    g.bench_function("bounded_full", |b| {
+        b.iter(|| {
+            rt.block_on(async move {
+                let (tx, mut rx) = mpsc::channel::<usize>(100);
 
-            for i in 0..5000 {
-                tx.send(i).unwrap();
-            }
+                for _ in 0..5 {
+                    let tx = tx.clone();
+                    tokio::spawn(async move {
+                        for i in 0..1000 {
+                            tx.send(i).await.unwrap();
+                        }
+                    });
+                }
 
-            for _ in 0..5_000 {
-                let _ = rx.recv().await;
-            }
+                for _ in 0..1_000 * 5 {
+                    let _ = rx.recv().await;
+                }
+            })
         })
     });
 }
 
-bencher::benchmark_group!(
-    create,
-    create_1_medium,
-    create_100_medium,
-    create_100_000_medium
-);
+fn contention_bounded_full_recv_many(g: &mut BenchmarkGroup<WallTime>) {
+    let rt = rt();
 
-bencher::benchmark_group!(send, send_medium, send_large);
+    g.bench_function("bounded_full_recv_many", |b| {
+        b.iter(|| {
+            rt.block_on(async move {
+                let (tx, mut rx) = mpsc::channel::<usize>(100);
 
-bencher::benchmark_group!(
-    contention,
-    contention_bounded,
-    contention_bounded_full,
-    contention_unbounded,
-    uncontented_bounded,
-    uncontented_unbounded
-);
+                for _ in 0..5 {
+                    let tx = tx.clone();
+                    tokio::spawn(async move {
+                        for i in 0..1000 {
+                            tx.send(i).await.unwrap();
+                        }
+                    });
+                }
 
-bencher::benchmark_main!(create, send, contention);
+                let mut buffer = Vec::<usize>::with_capacity(5_000);
+                let mut total = 0;
+                while total < 1_000 * 5 {
+                    total += rx.recv_many(&mut buffer, 5_000).await;
+                }
+            })
+        })
+    });
+}
+
+fn contention_unbounded(g: &mut BenchmarkGroup<WallTime>) {
+    let rt = rt();
+
+    g.bench_function("unbounded", |b| {
+        b.iter(|| {
+            rt.block_on(async move {
+                let (tx, mut rx) = mpsc::unbounded_channel::<usize>();
+
+                for _ in 0..5 {
+                    let tx = tx.clone();
+                    tokio::spawn(async move {
+                        for i in 0..1000 {
+                            tx.send(i).unwrap();
+                        }
+                    });
+                }
+
+                for _ in 0..1_000 * 5 {
+                    let _ = rx.recv().await;
+                }
+            })
+        })
+    });
+}
+
+fn contention_unbounded_recv_many(g: &mut BenchmarkGroup<WallTime>) {
+    let rt = rt();
+
+    g.bench_function("unbounded_recv_many", |b| {
+        b.iter(|| {
+            rt.block_on(async move {
+                let (tx, mut rx) = mpsc::unbounded_channel::<usize>();
+
+                for _ in 0..5 {
+                    let tx = tx.clone();
+                    tokio::spawn(async move {
+                        for i in 0..1000 {
+                            tx.send(i).unwrap();
+                        }
+                    });
+                }
+
+                let mut buffer = Vec::<usize>::with_capacity(5_000);
+                let mut total = 0;
+                while total < 1_000 * 5 {
+                    total += rx.recv_many(&mut buffer, 5_000).await;
+                }
+            })
+        })
+    });
+}
+
+fn uncontented_bounded(g: &mut BenchmarkGroup<WallTime>) {
+    let rt = rt();
+
+    g.bench_function("bounded", |b| {
+        b.iter(|| {
+            rt.block_on(async move {
+                let (tx, mut rx) = mpsc::channel::<usize>(1_000_000);
+
+                for i in 0..5000 {
+                    tx.send(i).await.unwrap();
+                }
+
+                for _ in 0..5_000 {
+                    let _ = rx.recv().await;
+                }
+            })
+        })
+    });
+}
+
+fn uncontented_bounded_recv_many(g: &mut BenchmarkGroup<WallTime>) {
+    let rt = rt();
+
+    g.bench_function("bounded_recv_many", |b| {
+        b.iter(|| {
+            rt.block_on(async move {
+                let (tx, mut rx) = mpsc::channel::<usize>(1_000_000);
+
+                for i in 0..5000 {
+                    tx.send(i).await.unwrap();
+                }
+
+                let mut buffer = Vec::<usize>::with_capacity(5_000);
+                let mut total = 0;
+                while total < 1_000 * 5 {
+                    total += rx.recv_many(&mut buffer, 5_000).await;
+                }
+            })
+        })
+    });
+}
+
+fn uncontented_unbounded(g: &mut BenchmarkGroup<WallTime>) {
+    let rt = rt();
+
+    g.bench_function("unbounded", |b| {
+        b.iter(|| {
+            rt.block_on(async move {
+                let (tx, mut rx) = mpsc::unbounded_channel::<usize>();
+
+                for i in 0..5000 {
+                    tx.send(i).unwrap();
+                }
+
+                for _ in 0..5_000 {
+                    let _ = rx.recv().await;
+                }
+            })
+        })
+    });
+}
+
+fn uncontented_unbounded_recv_many(g: &mut BenchmarkGroup<WallTime>) {
+    let rt = rt();
+
+    g.bench_function("unbounded_recv_many", |b| {
+        b.iter(|| {
+            rt.block_on(async move {
+                let (tx, mut rx) = mpsc::unbounded_channel::<usize>();
+
+                for i in 0..5000 {
+                    tx.send(i).unwrap();
+                }
+
+                let mut buffer = Vec::<usize>::with_capacity(5_000);
+                let mut total = 0;
+                while total < 1_000 * 5 {
+                    total += rx.recv_many(&mut buffer, 5_000).await;
+                }
+            })
+        })
+    });
+}
+
+fn bench_create_medium(c: &mut Criterion) {
+    let mut group = c.benchmark_group("create_medium");
+    create_medium::<1>(&mut group);
+    create_medium::<100>(&mut group);
+    create_medium::<100_000>(&mut group);
+    group.finish();
+}
+
+fn bench_send(c: &mut Criterion) {
+    let mut group = c.benchmark_group("send");
+    send_data::<Medium, 1000>(&mut group, "medium");
+    send_data::<Large, 1000>(&mut group, "large");
+    group.finish();
+}
+
+fn bench_contention(c: &mut Criterion) {
+    let mut group = c.benchmark_group("contention");
+    contention_bounded(&mut group);
+    contention_bounded_recv_many(&mut group);
+    contention_bounded_full(&mut group);
+    contention_bounded_full_recv_many(&mut group);
+    contention_unbounded(&mut group);
+    contention_unbounded_recv_many(&mut group);
+    group.finish();
+}
+
+fn bench_uncontented(c: &mut Criterion) {
+    let mut group = c.benchmark_group("uncontented");
+    uncontented_bounded(&mut group);
+    uncontented_bounded_recv_many(&mut group);
+    uncontented_unbounded(&mut group);
+    uncontented_unbounded_recv_many(&mut group);
+    group.finish();
+}
+
+criterion_group!(create, bench_create_medium);
+criterion_group!(send, bench_send);
+criterion_group!(contention, bench_contention);
+criterion_group!(uncontented, bench_uncontented);
+
+criterion_main!(create, send, contention, uncontented);

benches/sync_mpsc_oneshot.rs

@@ -1,27 +1,28 @@
-use bencher::{benchmark_group, benchmark_main, Bencher};
 use tokio::{
     runtime::Runtime,
     sync::{mpsc, oneshot},
 };
 
-fn request_reply_current_thread(b: &mut Bencher) {
+use criterion::{criterion_group, criterion_main, Criterion};
+
+fn request_reply_current_thread(c: &mut Criterion) {
     let rt = tokio::runtime::Builder::new_current_thread()
         .build()
         .unwrap();
 
-    request_reply(b, rt);
+    request_reply(c, rt);
 }
 
-fn request_reply_multi_threaded(b: &mut Bencher) {
+fn request_reply_multi_threaded(c: &mut Criterion) {
     let rt = tokio::runtime::Builder::new_multi_thread()
         .worker_threads(1)
         .build()
         .unwrap();
 
-    request_reply(b, rt);
+    request_reply(c, rt);
 }
 
-fn request_reply(b: &mut Bencher, rt: Runtime) {
+fn request_reply(b: &mut Criterion, rt: Runtime) {
     let tx = rt.block_on(async move {
         let (tx, mut rx) = mpsc::channel::<oneshot::Sender<()>>(10);
         tokio::spawn(async move {
@@ -32,22 +33,24 @@ fn request_reply(b: &mut Bencher, rt: Runtime) {
         tx
     });
 
-    b.iter(|| {
-        let task_tx = tx.clone();
-        rt.block_on(async move {
-            for _ in 0..1_000 {
-                let (o_tx, o_rx) = oneshot::channel();
-                task_tx.send(o_tx).await.unwrap();
-                let _ = o_rx.await;
-            }
+    b.bench_function("request_reply", |b| {
+        b.iter(|| {
+            let task_tx = tx.clone();
+            rt.block_on(async move {
+                for _ in 0..1_000 {
+                    let (o_tx, o_rx) = oneshot::channel();
+                    task_tx.send(o_tx).await.unwrap();
+                    let _ = o_rx.await;
+                }
+            })
         })
     });
 }
 
-benchmark_group!(
+criterion_group!(
     sync_mpsc_oneshot_group,
     request_reply_current_thread,
     request_reply_multi_threaded,
 );
 
-benchmark_main!(sync_mpsc_oneshot_group);
+criterion_main!(sync_mpsc_oneshot_group);

benches/sync_notify.rs

@@ -0,0 +1,104 @@
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::sync::Arc;
+
+use tokio::sync::Notify;
+
+use criterion::measurement::WallTime;
+use criterion::{criterion_group, criterion_main, BenchmarkGroup, Criterion};
+
+fn rt() -> tokio::runtime::Runtime {
+    tokio::runtime::Builder::new_multi_thread()
+        .worker_threads(6)
+        .build()
+        .unwrap()
+}
+
+fn notify_waiters<const N_WAITERS: usize>(g: &mut BenchmarkGroup<WallTime>) {
+    let rt = rt();
+    let notify = Arc::new(Notify::new());
+    let counter = Arc::new(AtomicUsize::new(0));
+    for _ in 0..N_WAITERS {
+        rt.spawn({
+            let notify = notify.clone();
+            let counter = counter.clone();
+            async move {
+                loop {
+                    notify.notified().await;
+                    counter.fetch_add(1, Ordering::Relaxed);
+                }
+            }
+        });
+    }
+
+    const N_ITERS: usize = 500;
+    g.bench_function(N_WAITERS.to_string(), |b| {
+        b.iter(|| {
+            counter.store(0, Ordering::Relaxed);
+            loop {
+                notify.notify_waiters();
+                if counter.load(Ordering::Relaxed) >= N_ITERS {
+                    break;
+                }
+            }
+        })
+    });
+}
+
+fn notify_one<const N_WAITERS: usize>(g: &mut BenchmarkGroup<WallTime>) {
+    let rt = rt();
+    let notify = Arc::new(Notify::new());
+    let counter = Arc::new(AtomicUsize::new(0));
+    for _ in 0..N_WAITERS {
+        rt.spawn({
+            let notify = notify.clone();
+            let counter = counter.clone();
+            async move {
+                loop {
+                    notify.notified().await;
+                    counter.fetch_add(1, Ordering::Relaxed);
+                }
+            }
+        });
+    }
+
+    const N_ITERS: usize = 500;
+    g.bench_function(N_WAITERS.to_string(), |b| {
+        b.iter(|| {
+            counter.store(0, Ordering::Relaxed);
+            loop {
+                notify.notify_one();
+                if counter.load(Ordering::Relaxed) >= N_ITERS {
+                    break;
+                }
+            }
+        })
+    });
+}
+
+fn bench_notify_one(c: &mut Criterion) {
+    let mut group = c.benchmark_group("notify_one");
+    notify_one::<10>(&mut group);
+    notify_one::<50>(&mut group);
+    notify_one::<100>(&mut group);
+    notify_one::<200>(&mut group);
+    notify_one::<500>(&mut group);
+    group.finish();
+}
+
+fn bench_notify_waiters(c: &mut Criterion) {
+    let mut group = c.benchmark_group("notify_waiters");
+    notify_waiters::<10>(&mut group);
+    notify_waiters::<50>(&mut group);
+    notify_waiters::<100>(&mut group);
+    notify_waiters::<200>(&mut group);
+    notify_waiters::<500>(&mut group);
+    group.finish();
+}
+
+criterion_group!(
+    notify_waiters_simple,
+    bench_notify_one,
+    bench_notify_waiters
+);
+
+criterion_main!(notify_waiters_simple);

benches/sync_rwlock.rs

@@ -1,26 +1,30 @@
-use bencher::{black_box, Bencher};
 use std::sync::Arc;
 use tokio::{sync::RwLock, task};
 
-fn read_uncontended(b: &mut Bencher) {
+use criterion::measurement::WallTime;
+use criterion::{black_box, criterion_group, criterion_main, BenchmarkGroup, Criterion};
+
+fn read_uncontended(g: &mut BenchmarkGroup<WallTime>) {
     let rt = tokio::runtime::Builder::new_multi_thread()
         .worker_threads(6)
         .build()
         .unwrap();
 
     let lock = Arc::new(RwLock::new(()));
-    b.iter(|| {
-        let lock = lock.clone();
-        rt.block_on(async move {
-            for _ in 0..6 {
-                let read = lock.read().await;
-                let _read = black_box(read);
-            }
+    g.bench_function("read", |b| {
+        b.iter(|| {
+            let lock = lock.clone();
+            rt.block_on(async move {
+                for _ in 0..6 {
+                    let read = lock.read().await;
+                    let _read = black_box(read);
+                }
+            })
         })
     });
 }
 
-fn read_concurrent_uncontended_multi(b: &mut Bencher) {
+fn read_concurrent_uncontended_multi(g: &mut BenchmarkGroup<WallTime>) {
     let rt = tokio::runtime::Builder::new_multi_thread()
         .worker_threads(6)
         .build()
@@ -32,23 +36,25 @@ fn read_concurrent_uncontended_multi(b: &mut Bencher) {
     }
 
     let lock = Arc::new(RwLock::new(()));
-    b.iter(|| {
-        let lock = lock.clone();
-        rt.block_on(async move {
-            let j = tokio::try_join! {
-                task::spawn(task(lock.clone())),
-                task::spawn(task(lock.clone())),
-                task::spawn(task(lock.clone())),
-                task::spawn(task(lock.clone())),
-                task::spawn(task(lock.clone())),
-                task::spawn(task(lock.clone()))
-            };
-            j.unwrap();
+    g.bench_function("read_concurrent_multi", |b| {
+        b.iter(|| {
+            let lock = lock.clone();
+            rt.block_on(async move {
+                let j = tokio::try_join! {
+                    task::spawn(task(lock.clone())),
+                    task::spawn(task(lock.clone())),
+                    task::spawn(task(lock.clone())),
+                    task::spawn(task(lock.clone())),
+                    task::spawn(task(lock.clone())),
+                    task::spawn(task(lock.clone()))
+                };
+                j.unwrap();
+            })
         })
     });
 }
 
-fn read_concurrent_uncontended(b: &mut Bencher) {
+fn read_concurrent_uncontended(g: &mut BenchmarkGroup<WallTime>) {
     let rt = tokio::runtime::Builder::new_current_thread()
         .build()
         .unwrap();
@@ -59,22 +65,24 @@ fn read_concurrent_uncontended(b: &mut Bencher) {
     }
 
     let lock = Arc::new(RwLock::new(()));
-    b.iter(|| {
-        let lock = lock.clone();
-        rt.block_on(async move {
-            tokio::join! {
-                task(lock.clone()),
-                task(lock.clone()),
-                task(lock.clone()),
-                task(lock.clone()),
-                task(lock.clone()),
-                task(lock.clone())
-            };
+    g.bench_function("read_concurrent", |b| {
+        b.iter(|| {
+            let lock = lock.clone();
+            rt.block_on(async move {
+                tokio::join! {
+                    task(lock.clone()),
+                    task(lock.clone()),
+                    task(lock.clone()),
+                    task(lock.clone()),
+                    task(lock.clone()),
+                    task(lock.clone())
+                };
+            })
         })
     });
 }
 
-fn read_concurrent_contended_multi(b: &mut Bencher) {
+fn read_concurrent_contended_multi(g: &mut BenchmarkGroup<WallTime>) {
     let rt = tokio::runtime::Builder::new_multi_thread()
         .worker_threads(6)
         .build()
@@ -86,24 +94,26 @@ fn read_concurrent_contended_multi(b: &mut Bencher) {
     }
 
     let lock = Arc::new(RwLock::new(()));
-    b.iter(|| {
-        let lock = lock.clone();
-        rt.block_on(async move {
-            let write = lock.write().await;
-            let j = tokio::try_join! {
-                async move { drop(write); Ok(()) },
-                task::spawn(task(lock.clone())),
-                task::spawn(task(lock.clone())),
-                task::spawn(task(lock.clone())),
-                task::spawn(task(lock.clone())),
-                task::spawn(task(lock.clone())),
-            };
-            j.unwrap();
+    g.bench_function("read_concurrent_multi", |b| {
+        b.iter(|| {
+            let lock = lock.clone();
+            rt.block_on(async move {
+                let write = lock.write().await;
+                let j = tokio::try_join! {
+                    async move { drop(write); Ok(()) },
+                    task::spawn(task(lock.clone())),
+                    task::spawn(task(lock.clone())),
+                    task::spawn(task(lock.clone())),
+                    task::spawn(task(lock.clone())),
+                    task::spawn(task(lock.clone())),
+                };
+                j.unwrap();
+            })
         })
     });
 }
 
-fn read_concurrent_contended(b: &mut Bencher) {
+fn read_concurrent_contended(g: &mut BenchmarkGroup<WallTime>) {
     let rt = tokio::runtime::Builder::new_current_thread()
         .build()
         .unwrap();
@@ -114,29 +124,40 @@ fn read_concurrent_contended(b: &mut Bencher) {
     }
 
     let lock = Arc::new(RwLock::new(()));
-    b.iter(|| {
-        let lock = lock.clone();
-        rt.block_on(async move {
-            let write = lock.write().await;
-            tokio::join! {
-                async move { drop(write) },
-                task(lock.clone()),
-                task(lock.clone()),
-                task(lock.clone()),
-                task(lock.clone()),
-                task(lock.clone()),
-            };
+    g.bench_function("read_concurrent", |b| {
+        b.iter(|| {
+            let lock = lock.clone();
+            rt.block_on(async move {
+                let write = lock.write().await;
+                tokio::join! {
+                    async move { drop(write) },
+                    task(lock.clone()),
+                    task(lock.clone()),
+                    task(lock.clone()),
+                    task(lock.clone()),
+                    task(lock.clone()),
+                };
+            })
         })
     });
 }
 
-bencher::benchmark_group!(
-    sync_rwlock,
-    read_uncontended,
-    read_concurrent_uncontended,
-    read_concurrent_uncontended_multi,
-    read_concurrent_contended,
-    read_concurrent_contended_multi
-);
+fn bench_contention(c: &mut Criterion) {
+    let mut group = c.benchmark_group("contention");
+    read_concurrent_contended(&mut group);
+    read_concurrent_contended_multi(&mut group);
+    group.finish();
+}
 
-bencher::benchmark_main!(sync_rwlock);
+fn bench_uncontented(c: &mut Criterion) {
+    let mut group = c.benchmark_group("uncontented");
+    read_uncontended(&mut group);
+    read_concurrent_uncontended(&mut group);
+    read_concurrent_uncontended_multi(&mut group);
+    group.finish();
+}
+
+criterion_group!(contention, bench_contention);
+criterion_group!(uncontented, bench_uncontented);
+
+criterion_main!(contention, uncontented);

benches/sync_semaphore.rs

@@ -1,21 +1,36 @@
-use bencher::Bencher;
 use std::sync::Arc;
+use tokio::runtime::Runtime;
 use tokio::{sync::Semaphore, task};
 
-fn uncontended(b: &mut Bencher) {
-    let rt = tokio::runtime::Builder::new_multi_thread()
+use criterion::measurement::WallTime;
+use criterion::{criterion_group, criterion_main, BenchmarkGroup, Criterion};
+
+fn single_rt() -> Runtime {
+    tokio::runtime::Builder::new_current_thread()
+        .build()
+        .unwrap()
+}
+
+fn multi_rt() -> Runtime {
+    tokio::runtime::Builder::new_multi_thread()
         .worker_threads(6)
         .build()
-        .unwrap();
+        .unwrap()
+}
+
+fn uncontended(g: &mut BenchmarkGroup<WallTime>) {
+    let rt = multi_rt();
 
     let s = Arc::new(Semaphore::new(10));
-    b.iter(|| {
-        let s = s.clone();
-        rt.block_on(async move {
-            for _ in 0..6 {
-                let permit = s.acquire().await;
-                drop(permit);
-            }
+    g.bench_function("multi", |b| {
+        b.iter(|| {
+            let s = s.clone();
+            rt.block_on(async move {
+                for _ in 0..6 {
+                    let permit = s.acquire().await;
+                    drop(permit);
+                }
+            })
         })
     });
 }
@@ -25,101 +40,108 @@ async fn task(s: Arc<Semaphore>) {
     drop(permit);
 }
 
-fn uncontended_concurrent_multi(b: &mut Bencher) {
-    let rt = tokio::runtime::Builder::new_multi_thread()
-        .worker_threads(6)
-        .build()
-        .unwrap();
+fn uncontended_concurrent_multi(g: &mut BenchmarkGroup<WallTime>) {
+    let rt = multi_rt();
 
     let s = Arc::new(Semaphore::new(10));
-    b.iter(|| {
-        let s = s.clone();
-        rt.block_on(async move {
-            let j = tokio::try_join! {
-                task::spawn(task(s.clone())),
-                task::spawn(task(s.clone())),
-                task::spawn(task(s.clone())),
-                task::spawn(task(s.clone())),
-                task::spawn(task(s.clone())),
-                task::spawn(task(s.clone()))
-            };
-            j.unwrap();
+    g.bench_function("concurrent_multi", |b| {
+        b.iter(|| {
+            let s = s.clone();
+            rt.block_on(async move {
+                let j = tokio::try_join! {
+                    task::spawn(task(s.clone())),
+                    task::spawn(task(s.clone())),
+                    task::spawn(task(s.clone())),
+                    task::spawn(task(s.clone())),
+                    task::spawn(task(s.clone())),
+                    task::spawn(task(s.clone()))
+                };
+                j.unwrap();
+            })
         })
     });
 }
 
-fn uncontended_concurrent_single(b: &mut Bencher) {
-    let rt = tokio::runtime::Builder::new_current_thread()
-        .build()
-        .unwrap();
+fn uncontended_concurrent_single(g: &mut BenchmarkGroup<WallTime>) {
+    let rt = single_rt();
 
     let s = Arc::new(Semaphore::new(10));
-    b.iter(|| {
-        let s = s.clone();
-        rt.block_on(async move {
-            tokio::join! {
-                task(s.clone()),
-                task(s.clone()),
-                task(s.clone()),
-                task(s.clone()),
-                task(s.clone()),
-                task(s.clone())
-            };
+    g.bench_function("concurrent_single", |b| {
+        b.iter(|| {
+            let s = s.clone();
+            rt.block_on(async move {
+                tokio::join! {
+                    task(s.clone()),
+                    task(s.clone()),
+                    task(s.clone()),
+                    task(s.clone()),
+                    task(s.clone()),
+                    task(s.clone())
+                };
+            })
         })
     });
 }
 
-fn contended_concurrent_multi(b: &mut Bencher) {
-    let rt = tokio::runtime::Builder::new_multi_thread()
-        .worker_threads(6)
-        .build()
-        .unwrap();
+fn contended_concurrent_multi(g: &mut BenchmarkGroup<WallTime>) {
+    let rt = multi_rt();
 
     let s = Arc::new(Semaphore::new(5));
-    b.iter(|| {
-        let s = s.clone();
-        rt.block_on(async move {
-            let j = tokio::try_join! {
-                task::spawn(task(s.clone())),
-                task::spawn(task(s.clone())),
-                task::spawn(task(s.clone())),
-                task::spawn(task(s.clone())),
-                task::spawn(task(s.clone())),
-                task::spawn(task(s.clone()))
-            };
-            j.unwrap();
+    g.bench_function("concurrent_multi", |b| {
+        b.iter(|| {
+            let s = s.clone();
+            rt.block_on(async move {
+                let j = tokio::try_join! {
+                    task::spawn(task(s.clone())),
+                    task::spawn(task(s.clone())),
+                    task::spawn(task(s.clone())),
+                    task::spawn(task(s.clone())),
+                    task::spawn(task(s.clone())),
+                    task::spawn(task(s.clone()))
+                };
+                j.unwrap();
+            })
         })
     });
 }
 
-fn contended_concurrent_single(b: &mut Bencher) {
-    let rt = tokio::runtime::Builder::new_current_thread()
-        .build()
-        .unwrap();
+fn contended_concurrent_single(g: &mut BenchmarkGroup<WallTime>) {
+    let rt = single_rt();
 
     let s = Arc::new(Semaphore::new(5));
-    b.iter(|| {
-        let s = s.clone();
-        rt.block_on(async move {
-            tokio::join! {
-                task(s.clone()),
-                task(s.clone()),
-                task(s.clone()),
-                task(s.clone()),
-                task(s.clone()),
-                task(s.clone())
-            };
+    g.bench_function("concurrent_single", |b| {
+        b.iter(|| {
+            let s = s.clone();
+            rt.block_on(async move {
+                tokio::join! {
+                    task(s.clone()),
+                    task(s.clone()),
+                    task(s.clone()),
+                    task(s.clone()),
+                    task(s.clone()),
+                    task(s.clone())
+                };
+            })
         })
     });
 }
 
-bencher::benchmark_group!(
-    sync_semaphore,
-    uncontended,
-    uncontended_concurrent_multi,
-    uncontended_concurrent_single,
-    contended_concurrent_multi,
-    contended_concurrent_single
-);
+fn bench_contention(c: &mut Criterion) {
+    let mut group = c.benchmark_group("contention");
+    contended_concurrent_multi(&mut group);
+    contended_concurrent_single(&mut group);
+    group.finish();
+}
 
-bencher::benchmark_main!(sync_semaphore);
+fn bench_uncontented(c: &mut Criterion) {
+    let mut group = c.benchmark_group("uncontented");
+    uncontended(&mut group);
+    uncontended_concurrent_multi(&mut group);
+    uncontended_concurrent_single(&mut group);
+    group.finish();
+}
+
+criterion_group!(contention, bench_contention);
+criterion_group!(uncontented, bench_uncontented);
+
+criterion_main!(contention, uncontented);

benches/sync_watch.rs

@@ -1,9 +1,11 @@
-use bencher::{black_box, Bencher};
 use rand::prelude::*;
 use std::sync::atomic::{AtomicU64, Ordering};
 use std::sync::Arc;
 use tokio::sync::{watch, Notify};
 
+use criterion::measurement::WallTime;
+use criterion::{black_box, criterion_group, criterion_main, BenchmarkGroup, Criterion};
+
 fn rt() -> tokio::runtime::Runtime {
     tokio::runtime::Builder::new_multi_thread()
         .worker_threads(6)
@@ -24,16 +26,15 @@ fn do_work(rng: &mut impl RngCore) -> u32 {
         .fold(0, u32::wrapping_add)
 }
 
-fn contention_resubscribe(b: &mut Bencher) {
-    const NTASK: u64 = 1000;
-
+fn contention_resubscribe<const N_TASKS: usize>(g: &mut BenchmarkGroup<WallTime>) {
     let rt = rt();
-    let (snd, rcv) = watch::channel(0i32);
+    let (snd, _) = watch::channel(0i32);
+    let snd = Arc::new(snd);
     let wg = Arc::new((AtomicU64::new(0), Notify::new()));
-    for n in 0..NTASK {
-        let mut rcv = rcv.clone();
+    for n in 0..N_TASKS {
+        let mut rcv = snd.subscribe();
         let wg = wg.clone();
-        let mut rng = rand::rngs::StdRng::seed_from_u64(n);
+        let mut rng = rand::rngs::StdRng::seed_from_u64(n as u64);
         rt.spawn(async move {
             while rcv.changed().await.is_ok() {
                 let _ = *rcv.borrow(); // contend on rwlock
@@ -46,19 +47,39 @@ fn contention_resubscribe(b: &mut Bencher) {
         });
     }
 
-    b.iter(|| {
-        rt.block_on(async {
-            for _ in 0..100 {
-                assert_eq!(wg.0.fetch_add(NTASK, Ordering::Relaxed), 0);
-                let _ = snd.send(black_box(42));
-                while wg.0.load(Ordering::Acquire) > 0 {
-                    wg.1.notified().await;
+    const N_ITERS: usize = 100;
+    g.bench_function(N_TASKS.to_string(), |b| {
+        b.iter(|| {
+            rt.block_on({
+                let snd = snd.clone();
+                let wg = wg.clone();
+                async move {
+                    tokio::spawn(async move {
+                        for _ in 0..N_ITERS {
+                            assert_eq!(wg.0.fetch_add(N_TASKS as u64, Ordering::Relaxed), 0);
+                            let _ = snd.send(black_box(42));
+                            while wg.0.load(Ordering::Acquire) > 0 {
+                                wg.1.notified().await;
+                            }
+                        }
+                    })
+                    .await
+                    .unwrap();
                 }
-            }
-        });
+            });
+        })
     });
 }
 
-bencher::benchmark_group!(contention, contention_resubscribe);
+fn bench_contention_resubscribe(c: &mut Criterion) {
+    let mut group = c.benchmark_group("contention_resubscribe");
+    contention_resubscribe::<10>(&mut group);
+    contention_resubscribe::<100>(&mut group);
+    contention_resubscribe::<500>(&mut group);
+    contention_resubscribe::<1000>(&mut group);
+    group.finish();
+}
 
-bencher::benchmark_main!(contention);
+criterion_group!(contention, bench_contention_resubscribe);
+
+criterion_main!(contention);

benches/time_now.rs

@@ -0,0 +1,24 @@
+//! Benchmark spawning a task onto the basic and threaded Tokio executors.
+//! This essentially measure the time to enqueue a task in the local and remote
+//! case.
+
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
+
+fn time_now_current_thread(c: &mut Criterion) {
+    let rt = tokio::runtime::Builder::new_current_thread()
+        .enable_time()
+        .build()
+        .unwrap();
+
+    c.bench_function("time_now_current_thread", |b| {
+        b.iter(|| {
+            rt.block_on(async {
+                black_box(tokio::time::Instant::now());
+            })
+        })
+    });
+}
+
+criterion_group!(time_now, time_now_current_thread);
+
+criterion_main!(time_now);

benches/time_timeout.rs

@@ -0,0 +1,109 @@
+use std::time::{Duration, Instant};
+
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
+use tokio::{
+    runtime::Runtime,
+    time::{sleep, timeout},
+};
+
+// a very quick async task, but might timeout
+async fn quick_job() -> usize {
+    1
+}
+
+fn build_run_time(workers: usize) -> Runtime {
+    if workers == 1 {
+        tokio::runtime::Builder::new_current_thread()
+            .enable_all()
+            .build()
+            .unwrap()
+    } else {
+        tokio::runtime::Builder::new_multi_thread()
+            .enable_all()
+            .worker_threads(workers)
+            .build()
+            .unwrap()
+    }
+}
+
+fn single_thread_scheduler_timeout(c: &mut Criterion) {
+    do_timeout_test(c, 1, "single_thread_timeout");
+}
+
+fn multi_thread_scheduler_timeout(c: &mut Criterion) {
+    do_timeout_test(c, 8, "multi_thread_timeout-8");
+}
+
+fn do_timeout_test(c: &mut Criterion, workers: usize, name: &str) {
+    let runtime = build_run_time(workers);
+    c.bench_function(name, |b| {
+        b.iter_custom(|iters| {
+            let start = Instant::now();
+            runtime.block_on(async {
+                black_box(spawn_timeout_job(iters as usize, workers)).await;
+            });
+            start.elapsed()
+        })
+    });
+}
+
+async fn spawn_timeout_job(iters: usize, procs: usize) {
+    let mut handles = Vec::with_capacity(procs);
+    for _ in 0..procs {
+        handles.push(tokio::spawn(async move {
+            for _ in 0..iters / procs {
+                let h = timeout(Duration::from_secs(1), quick_job());
+                assert_eq!(black_box(h.await.unwrap()), 1);
+            }
+        }));
+    }
+    for handle in handles {
+        handle.await.unwrap();
+    }
+}
+
+fn single_thread_scheduler_sleep(c: &mut Criterion) {
+    do_sleep_test(c, 1, "single_thread_sleep");
+}
+
+fn multi_thread_scheduler_sleep(c: &mut Criterion) {
+    do_sleep_test(c, 8, "multi_thread_sleep-8");
+}
+
+fn do_sleep_test(c: &mut Criterion, workers: usize, name: &str) {
+    let runtime = build_run_time(workers);
+
+    c.bench_function(name, |b| {
+        b.iter_custom(|iters| {
+            let start = Instant::now();
+            runtime.block_on(async {
+                black_box(spawn_sleep_job(iters as usize, workers)).await;
+            });
+            start.elapsed()
+        })
+    });
+}
+
+async fn spawn_sleep_job(iters: usize, procs: usize) {
+    let mut handles = Vec::with_capacity(procs);
+    for _ in 0..procs {
+        handles.push(tokio::spawn(async move {
+            for _ in 0..iters / procs {
+                let _h = black_box(sleep(Duration::from_secs(1)));
+            }
+        }));
+    }
+    for handle in handles {
+        handle.await.unwrap();
+    }
+}
+
+criterion_group!(
+    timeout_benchmark,
+    single_thread_scheduler_timeout,
+    multi_thread_scheduler_timeout,
+    single_thread_scheduler_sleep,
+    multi_thread_scheduler_sleep
+);
+
+criterion_main!(timeout_benchmark);

bin/publish

@@ -1,121 +0,0 @@
-#!/usr/bin/env bash
-set -e
-USAGE="Publish a new release of a tokio crate
-
-USAGE:
-    $(basename "$0") [OPTIONS] [CRATE] [VERSION]
-
-OPTIONS:
-    -v, --verbose   Use verbose Cargo output
-    -d, --dry-run   Perform a dry run (do not publish or tag the release)
-    -h, --help      Show this help text and exit"
-
-DRY_RUN=""
-VERBOSE=""
-
-err() {
-    echo -e "\e[31m\e[1merror:\e[0m $@" 1>&2;
-}
-
-status() {
-    WIDTH=12
-    printf "\e[32m\e[1m%${WIDTH}s\e[0m %s\n" "$1" "$2"
-}
-
-verify() {
-    status "Verifying" "if $CRATE v$VERSION can be released"
-    ACTUAL=$(cargo pkgid | sed -n 's/.*#\(.*\)/\1/p')
-
-    if [ "$ACTUAL" != "$VERSION" ]; then
-        err "expected to release version $VERSION, but Cargo.toml contained $ACTUAL"
-        exit 1
-    fi
-
-    if git tag -l | grep -Fxq "$TAG" ; then
-        err "git tag \`$TAG\` already exists"
-        exit 1
-    fi
-
-    PATH_DEPS=$(grep -F "path = \"" Cargo.toml | sed -e 's/^/  /')
-    if [ -n "$PATH_DEPS" ]; then
-        err "crate \`$CRATE\` contained path dependencies:\n$PATH_DEPS"
-        echo "path dependencies must be removed prior to release"
-        exit 1
-    fi
-}
-
-release() {
-    status "Releasing" "$CRATE v$VERSION"
-    cargo package $VERBOSE
-    cargo publish $VERBOSE $DRY_RUN
-
-    status "Tagging" "$TAG"
-    if [ -n "$DRY_RUN" ]; then
-        echo "# git tag $TAG && git push --tags"
-    else
-        git tag "$TAG" && git push --tags
-    fi
-}
-
-while [[ $# -gt 0 ]]
-do
-
-case "$1" in
-    -h|--help)
-    echo "$USAGE"
-    exit 0
-    ;;
-    -v|--verbose)
-    VERBOSE="--verbose"
-    set +x
-    shift
-    ;;
-    -d|--dry-run)
-    DRY_RUN="--dry-run"
-    shift
-    ;;
-    -*)
-    err "unknown flag \"$1\""
-    echo "$USAGE"
-    exit 1
-    ;;
-    *) # crate or version
-    if [ -z "$CRATE" ]; then
-        CRATE="$1"
-    elif [ -z "$VERSION" ]; then
-        VERSION="$1"
-    else
-        err "unknown positional argument \"$1\""
-        echo "$USAGE"
-        exit 1
-    fi
-    shift
-    ;;
-esac
-done
-# set -- "${POSITIONAL[@]}"
-
-if [ -z "$VERSION" ]; then
-    err "no version specified!"
-    HELP=1
-fi
-
-if [ -n "$CRATE" ]; then
-    TAG="$CRATE-$VERSION"
-else
-    err "no crate specified!"
-    HELP=1
-fi
-
-if [ -n "$HELP" ]; then
-    echo "$USAGE"
-    exit 1
-fi
-
-if [ -d "$CRATE" ]; then
-    (cd "$CRATE" && verify && release )
-else
-    err "no such crate \"$CRATE\""
-    exit 1
-fi
-

bin/update-doc

@@ -1,118 +0,0 @@
-#!/usr/bin/env bash
-set -e
-USAGE="Update links to docs.rs in a tokio crate
-
-USAGE:
-    $(basename "$0") [OPTIONS] [CRATE] [VERSION]
-
-OPTIONS:
-    -d, --dry-run       Perform a dry run (do not modify any file)
-    -h, --help          Show this help text and exit"
-
-err() {
-    echo -e "\e[31m\e[1merror:\e[0m $@" 1>&2;
-}
-
-status() {
-    WIDTH=12
-    printf "\e[32m\e[1m%${WIDTH}s\e[0m %s\n" "$1" "$2"
-}
-
-c1grep() { grep "$@" || test $? = 1; }
-
-update_versions_in_doc() {
-    # Print what is being/would be done
-    if [ -n "$DRY_RUN" ]; then
-        local MSG="Would change:"
-    else
-        local MSG="Updating:"
-    fi
-    git grep -lr "docs.rs/$CRATE/" \
-        | xargs sed --quiet \
-            -E "s|docs.rs/$CRATE/[0-9.]+|docs.rs/$CRATE/$VERSION|gp" \
-        | sed -e "s/^/$MSG /"
-
-    # Apply changes if not in dry run
-    if [ -z "$DRY_RUN" ]; then
-        git grep -lr "docs.rs/$CRATE/" \
-            | xargs sed -i \
-                -E "s|docs.rs/$CRATE/[0-9.]+|docs.rs/$CRATE/$VERSION|g"
-    fi
-}
-
-update() {
-    update_versions_in_doc
-}
-
-show_outdated() {
-    OUTDATED=$(git grep -rn "docs.rs/$CRATE/" \
-        | c1grep -v "$VERSION" \
-        | sed -e 's/^/ - /')
-    if [[ -n "$OUTDATED" ]]; then
-        echo "Found the following links to docs.rs with an outdated version:"
-        echo "$OUTDATED"
-        echo
-    else
-        echo "Nothing to do."
-        exit 1
-    fi
-}
-
-while [[ $# -gt 0 ]]
-do
-
-case "$1" in
-    -h|--help)
-    echo "$USAGE"
-    exit 0
-    ;;
-    -d|--dry-run)
-    DRY_RUN="--dry-run"
-    shift
-    ;;
-    -*)
-    err "unknown flag \"$1\""
-    echo "$USAGE"
-    exit 1
-    ;;
-    *) # crate or version
-    if [ -z "$CRATE" ]; then
-        CRATE="$1"
-    elif [ -z "$VERSION" ]; then
-        VERSION="$1"
-    else
-        err "unknown positional argument \"$1\""
-        echo "$USAGE"
-        exit 1
-    fi
-    shift
-    ;;
-esac
-done
-# set -- "${POSITIONAL[@]}"
-
-if [ -z "$VERSION" ]; then
-    err "no version specified!"
-    HELP=1
-fi
-
-if [ -n "$CRATE" ]; then
-    TAG="$CRATE-$VERSION"
-else
-    err "no crate specified!"
-    HELP=1
-fi
-
-if [ -n "$HELP" ]; then
-    echo "$USAGE"
-    exit 1
-fi
-
-if [ -d "$CRATE" ]; then
-    # Does not cd in order to update everywhere
-    show_outdated && update
-else
-    err "no such crate \"$CRATE\""
-    exit 1
-fi
-

deny.toml

@@ -0,0 +1,21 @@
+# https://embarkstudios.github.io/cargo-deny/cli/init.html
+
+[graph]
+all-features = true
+
+[licenses]
+allow = [
+    "MIT",
+    "Apache-2.0",
+]
+exceptions = [
+    { allow = ["Unicode-3.0", "Unicode-DFS-2016"], crate = "unicode-ident" },
+]
+
+[bans]
+multiple-versions = "allow"
+wildcards = "deny"
+
+[sources]
+unknown-registry = "deny"
+unknown-git = "deny"

examples/Cargo.toml

@@ -2,7 +2,8 @@
 name = "examples"
 version = "0.0.0"
 publish = false
-edition = "2018"
+edition = "2021"
+license = "MIT"
 
 # If you copy one of the examples into a new project, you should be using
 # [dependencies] instead, and delete the **path**.
@@ -25,7 +26,7 @@ once_cell = "1.5.2"
 rand = "0.8.3"
 
 [target.'cfg(windows)'.dev-dependencies.windows-sys]
-version = "0.45"
+version = "0.52"
 
 [[example]]
 name = "chat"
@@ -90,3 +91,10 @@ path = "named-pipe-ready.rs"
 [[example]]
 name = "named-pipe-multi-client"
 path = "named-pipe-multi-client.rs"
+
+[[example]]
+name = "dump"
+path = "dump.rs"
+
+[lints]
+workspace = true

examples/chat.rs

@@ -193,7 +193,7 @@ async fn process(
     // A client has connected, let's let everyone know.
     {
         let mut state = state.lock().await;
-        let msg = format!("{} has joined the chat", username);
+        let msg = format!("{username} has joined the chat");
         tracing::info!("{}", msg);
         state.broadcast(addr, &msg).await;
     }
@@ -210,7 +210,7 @@ async fn process(
                 // broadcast this message to the other users.
                 Some(Ok(msg)) => {
                     let mut state = state.lock().await;
-                    let msg = format!("{}: {}", username, msg);
+                    let msg = format!("{username}: {msg}");
 
                     state.broadcast(addr, &msg).await;
                 }
@@ -234,7 +234,7 @@ async fn process(
         let mut state = state.lock().await;
         state.peers.remove(&addr);
 
-        let msg = format!("{} has left the chat", username);
+        let msg = format!("{username} has left the chat");
         tracing::info!("{}", msg);
         state.broadcast(addr, &msg).await;
     }

examples/connect.rs

@@ -77,7 +77,7 @@ mod tcp {
                 //BytesMut into Bytes
                 Ok(i) => future::ready(Some(i.freeze())),
                 Err(e) => {
-                    println!("failed to read from socket; error={}", e);
+                    println!("failed to read from socket; error={e}");
                     future::ready(None)
                 }
             })

examples/custom-executor-tokio-context.rs

@@ -23,7 +23,7 @@ fn main() {
 
     // Without the `HandleExt.wrap()` there would be a panic because there is
     // no timer running, since it would be referencing runtime r1.
-    let _ = rt1.block_on(rt2.wrap(async move {
+    rt1.block_on(rt2.wrap(async move {
         let listener = TcpListener::bind("0.0.0.0:0").await.unwrap();
         println!("addr: {:?}", listener.local_addr());
         tx.send(()).unwrap();

examples/dump.rs

@@ -0,0 +1,93 @@
+#![allow(unknown_lints, unexpected_cfgs)]
+
+//! This example demonstrates tokio's experimental task dumping functionality.
+//! This application deadlocks. Input CTRL+C to display traces of each task, or
+//! input CTRL+C twice within 1 second to quit.
+
+#[cfg(all(
+    tokio_unstable,
+    tokio_taskdump,
+    target_os = "linux",
+    any(target_arch = "aarch64", target_arch = "x86", target_arch = "x86_64")
+))]
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    use std::sync::Arc;
+    use tokio::sync::Barrier;
+
+    #[inline(never)]
+    async fn a(barrier: Arc<Barrier>) {
+        b(barrier).await
+    }
+
+    #[inline(never)]
+    async fn b(barrier: Arc<Barrier>) {
+        c(barrier).await
+    }
+
+    #[inline(never)]
+    async fn c(barrier: Arc<Barrier>) {
+        barrier.wait().await;
+    }
+
+    // Prints a task dump upon receipt of CTRL+C, or returns if CTRL+C is
+    // inputted twice within a second.
+    async fn dump_or_quit() {
+        use tokio::time::{timeout, Duration, Instant};
+        let handle = tokio::runtime::Handle::current();
+        let mut last_signal: Option<Instant> = None;
+        // wait for CTRL+C
+        while let Ok(_) = tokio::signal::ctrl_c().await {
+            // exit if a CTRL+C is inputted twice within 1 second
+            if let Some(time_since_last_signal) = last_signal.map(|i| i.elapsed()) {
+                if time_since_last_signal < Duration::from_secs(1) {
+                    return;
+                }
+            }
+            last_signal = Some(Instant::now());
+
+            // capture a dump, and print each trace
+            println!("{:-<80}", "");
+            if let Ok(dump) = timeout(Duration::from_secs(2), handle.dump()).await {
+                for task in dump.tasks().iter() {
+                    let id = task.id();
+                    let trace = task.trace();
+                    println!("TASK {id}:");
+                    println!("{trace}\n");
+                }
+            } else {
+                println!("Task dumping timed out. Use a native debugger (like gdb) to debug the deadlock.");
+            }
+            println!("{:-<80}", "");
+            println!("Input CTRL+C twice within 1 second to exit.");
+        }
+    }
+
+    println!("This program has a deadlock.");
+    println!("Input CTRL+C to print a task dump.");
+    println!("Input CTRL+C twice within 1 second to exit.");
+
+    // oops! this barrier waits for one more task than will ever come.
+    let barrier = Arc::new(Barrier::new(3));
+
+    let task_1 = tokio::spawn(a(barrier.clone()));
+    let task_2 = tokio::spawn(a(barrier));
+
+    tokio::select!(
+        _ = dump_or_quit() => {},
+        _ = task_1 => {},
+        _ = task_2 => {},
+    );
+
+    Ok(())
+}
+
+#[cfg(not(all(
+    tokio_unstable,
+    tokio_taskdump,
+    target_os = "linux",
+    any(target_arch = "aarch64", target_arch = "x86", target_arch = "x86_64")
+)))]
+fn main() {
+    println!("task dumps are not available")
+}

examples/echo-udp.rs

@@ -38,7 +38,7 @@ impl Server {
             if let Some((size, peer)) = to_send {
                 let amt = socket.send_to(&buf[..size], &peer).await?;
 
-                println!("Echoed {}/{} bytes to {}", amt, size, peer);
+                println!("Echoed {amt}/{size} bytes to {peer}");
             }
 
             // If we're here then `to_send` is `None`, so we take a look for the

examples/echo.rs

@@ -40,7 +40,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
     // connections. This TCP listener is bound to the address we determined
     // above and must be associated with an event loop.
     let listener = TcpListener::bind(&addr).await?;
-    println!("Listening on: {}", addr);
+    println!("Listening on: {addr}");
 
     loop {
         // Asynchronously wait for an inbound socket.

examples/print_each_packet.rs

@@ -75,7 +75,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     // to our event loop. After the socket's created we inform that we're ready
     // to go and start accepting connections.
     let listener = TcpListener::bind(&addr).await?;
-    println!("Listening on: {}", addr);
+    println!("Listening on: {addr}");
 
     loop {
         // Asynchronously wait for an inbound socket.
@@ -96,8 +96,8 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
             // The stream will return None once the client disconnects.
             while let Some(message) = framed.next().await {
                 match message {
-                    Ok(bytes) => println!("bytes: {:?}", bytes),
-                    Err(err) => println!("Socket closed with error: {:?}", err),
+                    Ok(bytes) => println!("bytes: {bytes:?}"),
+                    Err(err) => println!("Socket closed with error: {err:?}"),
                 }
             }
             println!("Socket received FIN packet and closed connection");

examples/proxy.rs

@@ -22,8 +22,7 @@
 
 #![warn(rust_2018_idioms)]
 
-use tokio::io;
-use tokio::io::AsyncWriteExt;
+use tokio::io::copy_bidirectional;
 use tokio::net::{TcpListener, TcpStream};
 
 use futures::FutureExt;
@@ -39,41 +38,24 @@ async fn main() -> Result<(), Box<dyn Error>> {
         .nth(2)
         .unwrap_or_else(|| "127.0.0.1:8080".to_string());
 
-    println!("Listening on: {}", listen_addr);
-    println!("Proxying to: {}", server_addr);
+    println!("Listening on: {listen_addr}");
+    println!("Proxying to: {server_addr}");
 
     let listener = TcpListener::bind(listen_addr).await?;
 
-    while let Ok((inbound, _)) = listener.accept().await {
-        let transfer = transfer(inbound, server_addr.clone()).map(|r| {
-            if let Err(e) = r {
-                println!("Failed to transfer; error={}", e);
-            }
-        });
+    while let Ok((mut inbound, _)) = listener.accept().await {
+        let mut outbound = TcpStream::connect(server_addr.clone()).await?;
 
-        tokio::spawn(transfer);
+        tokio::spawn(async move {
+            copy_bidirectional(&mut inbound, &mut outbound)
+                .map(|r| {
+                    if let Err(e) = r {
+                        println!("Failed to transfer; error={e}");
+                    }
+                })
+                .await
+        });
     }
 
     Ok(())
 }
-
-async fn transfer(mut inbound: TcpStream, proxy_addr: String) -> Result<(), Box<dyn Error>> {
-    let mut outbound = TcpStream::connect(proxy_addr).await?;
-
-    let (mut ri, mut wi) = inbound.split();
-    let (mut ro, mut wo) = outbound.split();
-
-    let client_to_server = async {
-        io::copy(&mut ri, &mut wo).await?;
-        wo.shutdown().await
-    };
-
-    let server_to_client = async {
-        io::copy(&mut ro, &mut wi).await?;
-        wi.shutdown().await
-    };
-
-    tokio::try_join!(client_to_server, server_to_client)?;
-
-    Ok(())
-}

examples/tinydb.rs

@@ -90,7 +90,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
         .unwrap_or_else(|| "127.0.0.1:8080".to_string());
 
     let listener = TcpListener::bind(&addr).await?;
-    println!("Listening on: {}", addr);
+    println!("Listening on: {addr}");
 
     // Create the shared state of this server that will be shared amongst all
     // clients. We populate the initial database and then create the `Database`
@@ -131,11 +131,11 @@ async fn main() -> Result<(), Box<dyn Error>> {
                                 let response = response.serialize();
 
                                 if let Err(e) = lines.send(response.as_str()).await {
-                                    println!("error on sending response; error = {:?}", e);
+                                    println!("error on sending response; error = {e:?}");
                                 }
                             }
                             Err(e) => {
-                                println!("error on decoding from socket; error = {:?}", e);
+                                println!("error on decoding from socket; error = {e:?}");
                             }
                         }
                     }
@@ -143,7 +143,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
                     // The connection will be closed at this point as `lines.next()` has returned `None`.
                 });
             }
-            Err(e) => println!("error accepting socket; error = {:?}", e),
+            Err(e) => println!("error accepting socket; error = {e:?}"),
         }
     }
 }
@@ -162,7 +162,7 @@ fn handle_request(line: &str, db: &Arc<Database>) -> Response {
                 value: value.clone(),
             },
             None => Response::Error {
-                msg: format!("no key {}", key),
+                msg: format!("no key {key}"),
             },
         },
         Request::Set { key, value } => {
@@ -203,7 +203,7 @@ impl Request {
                     value: value.to_string(),
                 })
             }
-            Some(cmd) => Err(format!("unknown command: {}", cmd)),
+            Some(cmd) => Err(format!("unknown command: {cmd}")),
             None => Err("empty input".into()),
         }
     }
@@ -212,13 +212,13 @@ impl Request {
 impl Response {
     fn serialize(&self) -> String {
         match *self {
-            Response::Value { ref key, ref value } => format!("{} = {}", key, value),
+            Response::Value { ref key, ref value } => format!("{key} = {value}"),
             Response::Set {
                 ref key,
                 ref value,
                 ref previous,
-            } => format!("set {} = `{}`, previous: {:?}", key, value, previous),
-            Response::Error { ref msg } => format!("error: {}", msg),
+            } => format!("set {key} = `{value}`, previous: {previous:?}"),
+            Response::Error { ref msg } => format!("error: {msg}"),
         }
     }
 }

examples/tinyhttp.rs

@@ -31,13 +31,13 @@ async fn main() -> Result<(), Box<dyn Error>> {
         .nth(1)
         .unwrap_or_else(|| "127.0.0.1:8080".to_string());
     let server = TcpListener::bind(&addr).await?;
-    println!("Listening on: {}", addr);
+    println!("Listening on: {addr}");
 
     loop {
         let (stream, _) = server.accept().await?;
         tokio::spawn(async move {
             if let Err(e) = process(stream).await {
-                println!("failed to process connection; error = {}", e);
+                println!("failed to process connection; error = {e}");
             }
         });
     }
@@ -159,7 +159,7 @@ impl Decoder for Http {
             let mut parsed_headers = [httparse::EMPTY_HEADER; 16];
             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);
+                let msg = format!("failed to parse http request: {e:?}");
                 io::Error::new(io::ErrorKind::Other, msg)
             })?;
 
@@ -180,8 +180,11 @@ 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))?;
+
             (
-                toslice(r.method.unwrap().as_bytes()),
+                method,
                 toslice(r.path.unwrap().as_bytes()),
                 r.version.unwrap(),
                 amt,
@@ -195,7 +198,7 @@ impl Decoder for Http {
         }
         let data = src.split_to(amt).freeze();
         let mut ret = Request::builder();
-        ret = ret.method(&data[method.0..method.1]);
+        ret = ret.method(method);
         let s = data.slice(path.0..path.1);
         let s = unsafe { String::from_utf8_unchecked(Vec::from(s.as_ref())) };
         ret = ret.uri(s);
@@ -256,11 +259,11 @@ mod date {
         unix_date: u64,
     }
 
-    thread_local!(static LAST: RefCell<LastRenderedNow> = RefCell::new(LastRenderedNow {
+    thread_local!(static LAST: RefCell<LastRenderedNow> = const { RefCell::new(LastRenderedNow {
         bytes: [0; 128],
         amt: 0,
         unix_date: 0,
-    }));
+    }) });
 
     impl fmt::Display for Now {
         fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {

examples/udp-codec.rs

@@ -46,7 +46,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
 
     // Run both futures simultaneously of `a` and `b` sending messages back and forth.
     match tokio::try_join!(a, b) {
-        Err(e) => println!("an error occurred; error = {:?}", e),
+        Err(e) => println!("an error occurred; error = {e:?}"),
         _ => println!("done!"),
     }
 

netlify.toml

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

spellcheck.dic

@@ -0,0 +1,300 @@
+298
+&
++
+<
+=
+>
+\
+~
+—
+0o777
+0s
+0xA
+0xD
+100ms
+100ns
+10ms
+10μs
+~12
+120s
+12.5%
+±1m
+±1ms
+1ms
+1s
+25%
+250ms
+2x
+~4
+443
+450ms
+50ms
+8MB
+ABI
+accessors
+adaptor
+adaptors
+Adaptors
+AIO
+ambient
+amongst
+api
+APIs
+async
+atomics
+awaitable
+backend
+backpressure
+backtrace
+backtraces
+backtracing
+binded
+bitfield
+bitfields
+Blockingly
+boolean
+broadcasted
+cancelled
+cancelling
+Cancelling
+CLI
+cloneable
+codebase
+codec
+codecs
+combinator
+combinators
+config
+Config
+connectionless
+coroutines
+cpu
+cpus
+Customizable
+datagram
+Datagram
+datagrams
+deallocate
+deallocated
+Deallocates
+debuginfo
+decrementing
+demangled
+dequeued
+dereferenced
+deregister
+deregistered
+deregistering
+deregisters
+Deregisters
+deregistration
+descriptor's
+destructor
+destructors
+destructure
+Destructures
+Dev
+dns
+DNS
+DoS
+dwOpenMode
+endian
+enqueue
+enqueued
+EntryInner
+enum
+eof
+Erlang's
+errored
+EWMA
+expirations
+fcntl
+fd
+fd's
+FIFOs
+filename
+filesystem
+filesystems
+fn
+fns
+FreeBSD
+frontend
+fs
+functionalities
+getters
+GID
+goroutines
+Growable
+gzip
+H2
+hashmaps
+HashMaps
+hashsets
+HdrHistogram
+ie
+Illumos
+impl
+implementers
+implementor
+implementors
+incrementing
+inlining
+interoperate
+invariants
+Invariants
+io
+IOCP
+iOS
+IOs
+io_uring
+IP
+IPv4
+IPv6
+iteratively
+Kotlin's
+latencies
+Lauck
+libc
+lifecycle
+lifo
+lookups
+macOS
+MacOS
+Marsaglia's
+metadata
+mio
+Mio
+mio's
+miri
+misconfigured
+mock's
+mpmc
+mpsc
+multi
+Multi
+multicast
+Multithreaded
+mut
+mutex
+Mutex
+Nagle
+nonblocking
+nondecreasing
+noop
+ntasks
+ok
+oneshot
+ORed
+os
+overweighing
+parker
+parsers
+peekable
+PGID
+PID
+plaintext
+poller
+POSIX
+proxied
+qos
+RAII
+reallocations
+recv's
+refactors
+refcount
+refcounting
+repo
+repr
+representable
+reqwest
+reregistering
+resize
+resized
+RMW
+runtime
+runtime's
+runtimes
+rwlock
+rx
+scalability
+scheduler's
+semver
+setpgid
+sharded
+signalled
+signalling
+SmallCrush
+Solaris
+spawner
+Splitter
+spmc
+spsc
+src
+stabilised
+startup
+stateful
+stderr
+stdin
+stdout
+stealable
+stealer
+stealers
+struct
+structs
+subfield
+suboptimal
+subprocess
+superset
+symlink
+symlinks
+sys
+syscall
+syscalls
+tcp
+TCP
+TestU01
+threadpool
+timestamp
+timestamps
+TLS
+TOCTOU
+TODO
+tokio
+Tokio
+tokio's
+Tokio's
+tuple
+Tuple
+tx
+udp
+UDP
+UID
+unhandled
+unix
+unlink
+unpark
+Unpark
+unparked
+unparking
+unparks
+Unparks
+unreceived
+unsafety
+unsets
+Unsets
+unsynchronized
+untrusted
+usecases
+Valgrind
+Varghese
+vec
+versa
+versioned
+versioning
+vtable
+waker
+wakers
+Wakers
+wakeup
+wakeups
+workstealing

spellcheck.toml

@@ -0,0 +1,13 @@
+dev_comments = false
+skip_readme = false
+
+[Hunspell]
+lang = "en_US"
+search_dirs = ["."]
+extra_dictionaries = ["spellcheck.dic"]
+skip_os_lookups = true
+use_builtin = true
+
+[Hunspell.quirks]
+allow_concatenation = true
+

stress-test/Cargo.toml

@@ -2,13 +2,14 @@
 name = "stress-test"
 version = "0.1.0"
 authors = ["Tokio Contributors <[email protected]>"]
-edition = "2018"
+edition = "2021"
+license = "MIT"
 publish = false
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-tokio = { path = "../tokio/", features = ["full"] }
+tokio = { version = "1.0.0", path = "../tokio/", features = ["full"] }
 
 [dev-dependencies]
 rand = "0.8"

stress-test/examples/simple_echo_tcp.rs

@@ -42,7 +42,7 @@ fn main() {
                 .write_all(one_mega_random_bytes.as_slice())
                 .await
                 .unwrap();
-            stream.read(&mut buff).await.unwrap();
+            let _ = stream.read(&mut buff).await.unwrap();
         }
         tx.send(()).unwrap();
     });

target-specs/README.md

@@ -0,0 +1,9 @@
+This is used for the `no-atomic-u64-test` ci check that verifies that Tokio
+works even if the `AtomicU64` type is missing.
+
+When increasing the nightly compiler version, you may need to regenerate this
+target using the following command:
+```
+rustc +nightly -Z unstable-options --print target-spec-json --target i686-unknown-linux-gnu | grep -v 'is-builtin' | sed 's/"max-atomic-width": 64/"max-atomic-width": 32/' > target-specs/i686-unknown-linux-gnu.json
+```
+

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

@@ -1,29 +1,35 @@
 {
   "arch": "x86",
   "cpu": "pentium4",
+  "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-f64:32:64-f80:32-n8:16:32-S128",
+  "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",
   "dynamic-linking": true,
   "env": "gnu",
   "has-rpath": true,
   "has-thread-local": true,
+  "linker-flavor": "gnu-cc",
   "llvm-target": "i686-unknown-linux-gnu",
   "max-atomic-width": 32,
+  "metadata": {
+    "description": null,
+    "host_tools": null,
+    "std": null,
+    "tier": null
+  },
   "os": "linux",
   "position-independent-executables": true,
   "pre-link-args": {
-    "gcc": [
+    "gnu-cc": [
+      "-m32"
+    ],
+    "gnu-lld-cc": [
       "-m32"
     ]
   },
   "relro-level": "full",
   "stack-probes": {
-    "kind": "inline-or-call",
-    "min-llvm-version-for-inline": [
-      16,
-      0,
-      0
-    ]
+    "kind": "inline"
   },
   "supported-sanitizers": [
     "address"

tests-build/Cargo.toml

@@ -2,7 +2,8 @@
 name = "tests-build"
 version = "0.1.0"
 authors = ["Tokio Contributors <[email protected]>"]
-edition = "2018"
+edition = "2021"
+license = "MIT"
 publish = false
 
 [features]
@@ -10,7 +11,7 @@ full = ["tokio/full"]
 rt = ["tokio/rt", "tokio/macros"]
 
 [dependencies]
-tokio = { path = "../tokio", optional = true }
+tokio = { version = "1.0.0", path = "../tokio", optional = true }
 
 [dev-dependencies]
 trybuild = "1.0"

tests-build/README.md

@@ -6,5 +6,5 @@ To run all of the tests in this directory, run the following commands:
 cargo test --features full
 cargo test --features rt
 ```
-If one of the tests fail, you can pass `TRYBUILD=overwrite` to the `cargo test`
+If any of the tests fail, you can pass `TRYBUILD=overwrite` to the `cargo test`
 command that failed to have it regenerate the test output.

tests-build/tests/fail/macros_invalid_input.rs

@@ -36,16 +36,36 @@ async fn test_worker_threads_not_int() {}
 async fn test_worker_threads_and_current_thread() {}
 
 #[tokio::test(crate = 456)]
-async fn test_crate_not_ident_int() {}
+async fn test_crate_not_path_int() {}
 
 #[tokio::test(crate = "456")]
-async fn test_crate_not_ident_invalid() {}
+async fn test_crate_not_path_invalid() {}
 
-#[tokio::test(crate = "abc::edf")]
-async fn test_crate_not_ident_path() {}
+#[tokio::test(flavor = "multi_thread", unhandled_panic = "shutdown_runtime")]
+async fn test_multi_thread_with_unhandled_panic() {}
 
 #[tokio::test]
 #[test]
 async fn test_has_second_test_attr() {}
 
+#[tokio::test]
+#[::core::prelude::v1::test]
+async fn test_has_second_test_attr_v1() {}
+
+#[tokio::test]
+#[core::prelude::rust_2015::test]
+async fn test_has_second_test_attr_rust_2015() {}
+
+#[tokio::test]
+#[::std::prelude::rust_2018::test]
+async fn test_has_second_test_attr_rust_2018() {}
+
+#[tokio::test]
+#[std::prelude::rust_2021::test]
+async fn test_has_second_test_attr_rust_2021() {}
+
+#[tokio::test]
+#[tokio::test]
+async fn test_has_generated_second_test_attr() {}
+
 fn main() {}

tests-build/tests/fail/macros_invalid_input.stderr

@@ -1,101 +1,121 @@
 error: the `async` keyword is missing from the function declaration
- --> $DIR/macros_invalid_input.rs:6:1
+ --> tests/fail/macros_invalid_input.rs:6:1
   |
 6 | fn main_is_not_async() {}
   | ^^
 
-error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`
- --> $DIR/macros_invalid_input.rs:8:15
+error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`, `unhandled_panic`.
+ --> tests/fail/macros_invalid_input.rs:8:15
   |
 8 | #[tokio::main(foo)]
   |               ^^^
 
 error: Must have specified ident
-  --> $DIR/macros_invalid_input.rs:11:15
+  --> tests/fail/macros_invalid_input.rs:11:15
    |
 11 | #[tokio::main(threadpool::bar)]
    |               ^^^^^^^^^^^^^^^
 
 error: the `async` keyword is missing from the function declaration
-  --> $DIR/macros_invalid_input.rs:15:1
+  --> tests/fail/macros_invalid_input.rs:15:1
    |
 15 | fn test_is_not_async() {}
    | ^^
 
-error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`
-  --> $DIR/macros_invalid_input.rs:17:15
+error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`, `unhandled_panic`.
+  --> 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`
-  --> $DIR/macros_invalid_input.rs:20:15
+error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`, `unhandled_panic`
+  --> tests/fail/macros_invalid_input.rs:20:15
    |
 20 | #[tokio::test(foo = 123)]
    |               ^^^^^^^^^
 
 error: Failed to parse value of `flavor` as string.
-  --> $DIR/macros_invalid_input.rs:23:24
+  --> tests/fail/macros_invalid_input.rs:23:24
    |
 23 | #[tokio::test(flavor = 123)]
    |                        ^^^
 
 error: No such runtime flavor `foo`. The runtime flavors are `current_thread` and `multi_thread`.
-  --> $DIR/macros_invalid_input.rs:26:24
+  --> tests/fail/macros_invalid_input.rs:26:24
    |
 26 | #[tokio::test(flavor = "foo")]
    |                        ^^^^^
 
 error: The `start_paused` option requires the `current_thread` runtime flavor. Use `#[tokio::test(flavor = "current_thread")]`
-  --> $DIR/macros_invalid_input.rs:29:55
+  --> tests/fail/macros_invalid_input.rs:29:55
    |
 29 | #[tokio::test(flavor = "multi_thread", start_paused = false)]
    |                                                       ^^^^^
 
 error: Failed to parse value of `worker_threads` as integer.
-  --> $DIR/macros_invalid_input.rs:32:57
+  --> tests/fail/macros_invalid_input.rs:32:57
    |
 32 | #[tokio::test(flavor = "multi_thread", worker_threads = "foo")]
    |                                                         ^^^^^
 
 error: The `worker_threads` option requires the `multi_thread` runtime flavor. Use `#[tokio::test(flavor = "multi_thread")]`
-  --> $DIR/macros_invalid_input.rs:35:59
+  --> tests/fail/macros_invalid_input.rs:35:59
    |
 35 | #[tokio::test(flavor = "current_thread", worker_threads = 4)]
    |                                                           ^
 
-error: Failed to parse value of `crate` as ident.
-  --> $DIR/macros_invalid_input.rs:38:23
+error: Failed to parse value of `crate` as path.
+  --> tests/fail/macros_invalid_input.rs:38:23
    |
 38 | #[tokio::test(crate = 456)]
    |                       ^^^
 
-error: Failed to parse value of `crate` as ident: "456"
-  --> $DIR/macros_invalid_input.rs:41:23
+error: Failed to parse value of `crate` as path: "456"
+  --> tests/fail/macros_invalid_input.rs:41:23
    |
 41 | #[tokio::test(crate = "456")]
    |                       ^^^^^
 
-error: Failed to parse value of `crate` as ident: "abc::edf"
-  --> $DIR/macros_invalid_input.rs:44:23
+error: The `unhandled_panic` option requires the `current_thread` runtime flavor. Use `#[tokio::test(flavor = "current_thread")]`
+  --> tests/fail/macros_invalid_input.rs:44:58
    |
-44 | #[tokio::test(crate = "abc::edf")]
-   |                       ^^^^^^^^^^
+44 | #[tokio::test(flavor = "multi_thread", unhandled_panic = "shutdown_runtime")]
+   |                                                          ^^^^^^^^^^^^^^^^^^
 
-error: second test attribute is supplied
-  --> $DIR/macros_invalid_input.rs:48:1
+error: second test attribute is supplied, consider removing or changing the order of your test attributes
+  --> tests/fail/macros_invalid_input.rs:48:1
    |
 48 | #[test]
    | ^^^^^^^
 
-error: duplicated attribute
-  --> $DIR/macros_invalid_input.rs:48:1
+error: second test attribute is supplied, consider removing or changing the order of your test attributes
+  --> tests/fail/macros_invalid_input.rs:52:1
    |
-48 | #[test]
-   | ^^^^^^^
+52 | #[::core::prelude::v1::test]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: second test attribute is supplied, consider removing or changing the order of your test attributes
+  --> tests/fail/macros_invalid_input.rs:56:1
    |
-note: the lint level is defined here
-  --> $DIR/macros_invalid_input.rs:1:9
+56 | #[core::prelude::rust_2015::test]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: second test attribute is supplied, consider removing or changing the order of your test attributes
+  --> tests/fail/macros_invalid_input.rs:60:1
    |
-1  | #![deny(duplicate_macro_attributes)]
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
+60 | #[::std::prelude::rust_2018::test]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: second test attribute is supplied, consider removing or changing the order of your test attributes
+  --> tests/fail/macros_invalid_input.rs:64:1
+   |
+64 | #[std::prelude::rust_2021::test]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: second test attribute is supplied, consider removing or changing the order of your test attributes
+  --> tests/fail/macros_invalid_input.rs:67:1
+   |
+67 | #[tokio::test]
+   | ^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the attribute macro `tokio::test` (in Nightly builds, run with -Z macro-backtrace for more info)

tests-build/tests/fail/macros_type_mismatch.stderr

@@ -1,33 +1,45 @@
 error[E0308]: mismatched types
- --> $DIR/macros_type_mismatch.rs:5:5
+ --> tests/fail/macros_type_mismatch.rs:5:5
   |
-4 | async fn missing_semicolon_or_return_type() {
-  |                                             - help: a return type might be missing here: `-> _`
 5 |     Ok(())
-  |     ^^^^^^ expected `()`, found enum `Result`
+  |     ^^^^^^ expected `()`, found `Result<(), _>`
   |
   = note: expected unit type `()`
                   found enum `Result<(), _>`
+help: a return type might be missing here
+  |
+4 | async fn missing_semicolon_or_return_type() -> _ {
+  |                                             ++++
+help: consider using `Result::expect` to unwrap the `Result<(), _>` value, panicking if the value is a `Result::Err`
+  |
+5 |     Ok(()).expect("REASON")
+  |           +++++++++++++++++
 
 error[E0308]: mismatched types
-  --> $DIR/macros_type_mismatch.rs:10:5
+  --> tests/fail/macros_type_mismatch.rs:10:5
    |
-9  | async fn missing_return_type() {
-   |                                - help: a return type might be missing here: `-> _`
 10 |     return Ok(());
-   |     ^^^^^^^^^^^^^^ expected `()`, found enum `Result`
+   |     ^^^^^^^^^^^^^^ expected `()`, found `Result<(), _>`
    |
    = note: expected unit type `()`
                    found enum `Result<(), _>`
+help: a return type might be missing here
+   |
+ 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[E0308]: mismatched types
-  --> $DIR/macros_type_mismatch.rs:23:5
+  --> tests/fail/macros_type_mismatch.rs:23:5
    |
 14 | async fn extra_semicolon() -> Result<(), ()> {
    |                               -------------- expected `Result<(), ()>` because of return type
 ...
 23 |     Ok(());
-   |     ^^^^^^^ expected enum `Result`, found `()`
+   |     ^^^^^^^ expected `Result<(), ()>`, found `()`
    |
    = note:   expected enum `Result<(), ()>`
            found unit type `()`
@@ -38,10 +50,10 @@ help: try adding an expression at the end of the block
    |
 
 error[E0308]: mismatched types
-  --> $DIR/macros_type_mismatch.rs:32:5
+  --> tests/fail/macros_type_mismatch.rs:32:5
    |
 30 | async fn issue_4635() {
-   |                       - help: try adding a return type: `-> i32`
+   |                      - help: try adding a return type: `-> i32`
 31 |     return 1;
 32 |     ;
    |     ^ expected `()`, found integer

tests-build/tests/macros.rs

@@ -1,4 +1,5 @@
 #[test]
+#[cfg_attr(miri, ignore)]
 fn compile_fail_full() {
     let t = trybuild::TestCases::new();
 

tests-integration/Cargo.toml

@@ -2,7 +2,8 @@
 name = "tests-integration"
 version = "0.1.0"
 authors = ["Tokio Contributors <[email protected]>"]
-edition = "2018"
+edition = "2021"
+license = "MIT"
 publish = false
 
 [[bin]]
@@ -39,6 +40,7 @@ rt-process-signal = ["rt-net", "tokio/process", "tokio/signal"]
 # This is an explicit feature so we can use `cargo hack` testing single features
 # instead of all possible permutations.
 wasi-rt = ["rt", "macros", "sync"]
+wasi-threads-rt = ["wasi-rt", "rt-multi-thread"]
 
 full = [
     "macros",
@@ -54,8 +56,8 @@ rt = ["tokio/rt"]
 rt-multi-thread = ["rt", "tokio/rt-multi-thread"]
 
 [dependencies]
-tokio = { path = "../tokio" }
-tokio-test = { path = "../tokio-test", optional = true }
+tokio = { version = "1.0.0", path = "../tokio" }
+tokio-test = { version = "0.4", path = "../tokio-test", optional = true }
 doc-comment = "0.3.1"
 futures = { version = "0.3.0", features = ["async-await"] }
 bytes = "1.0.0"

tests-integration/src/bin/test-mem.rs

@@ -1,4 +1,4 @@
-use futures::future::poll_fn;
+use std::future::poll_fn;
 
 fn main() {
     let rt = tokio::runtime::Builder::new_multi_thread()

tests-integration/tests/macros_main.rs

@@ -1,8 +1,4 @@
-#![cfg(all(
-    feature = "macros",
-    feature = "rt-multi-thread",
-    not(target_os = "wasi")
-))]
+#![cfg(all(feature = "macros", feature = "rt-multi-thread"))]
 
 #[tokio::main]
 async fn basic_main() -> usize {

tests-integration/tests/macros_select.rs

@@ -4,7 +4,10 @@ use futures::channel::oneshot;
 use futures::executor::block_on;
 use std::thread;
 
-#[cfg_attr(target_os = "wasi", ignore = "WASI: std::thread::spawn not supported")]
+#[cfg_attr(
+    not(feature = "rt-multi-thread"),
+    ignore = "WASI: std::thread::spawn not supported"
+)]
 #[test]
 fn join_with_select() {
     block_on(async {

tests-integration/tests/process_stdio.rs

@@ -1,5 +1,5 @@
 #![warn(rust_2018_idioms)]
-#![cfg(all(feature = "full", not(target_os = "wasi")))]
+#![cfg(all(feature = "full", not(target_os = "wasi"), not(miri)))]
 
 use tokio::io::{AsyncBufReadExt, AsyncReadExt, AsyncWriteExt, BufReader};
 use tokio::join;
@@ -7,10 +7,10 @@ use tokio::process::{Child, Command};
 use tokio_test::assert_ok;
 
 use futures::future::{self, FutureExt};
-use std::convert::TryInto;
 use std::env;
 use std::io;
 use std::process::{ExitStatus, Stdio};
+use std::task::ready;
 
 fn cat() -> Command {
     let mut cmd = Command::new(env!("CARGO_BIN_EXE_test-cat"));
@@ -206,13 +206,13 @@ async fn vectored_writes() {
         let mut input = Bytes::from_static(b"hello\n").chain(Bytes::from_static(b"world!\n"));
         let mut writes_completed = 0;
 
-        futures::future::poll_fn(|cx| loop {
+        std::future::poll_fn(|cx| loop {
             let mut slices = [IoSlice::new(&[]); 2];
             let vectored = input.chunks_vectored(&mut slices);
             if vectored == 0 {
                 return std::task::Poll::Ready(std::io::Result::Ok(()));
             }
-            let n = futures::ready!(Pin::new(&mut stdin).poll_write_vectored(cx, &slices))?;
+            let n = ready!(Pin::new(&mut stdin).poll_write_vectored(cx, &slices))?;
             writes_completed += 1;
             input.advance(n);
         })

tokio-macros/CHANGELOG.md

@@ -1,3 +1,54 @@
+# 2.5.0 (Jan 8th, 2025)
+
+- macros: suppress `clippy::needless_return` in `#[tokio::main]` ([#6874])
+
+[#6874]: https://github.com/tokio-rs/tokio/pull/6874
+
+# 2.4.0 (July 22nd, 2024)
+
+- msrv: increase MSRV to 1.70 ([#6645])
+- macros: allow `unhandled_panic` behavior for `#[tokio::main]` and `#[tokio::test]` ([#6593])
+
+[#6593]: https://github.com/tokio-rs/tokio/pull/6593
+[#6645]: https://github.com/tokio-rs/tokio/pull/6645
+
+# 2.3.0 (May 30th, 2024)
+
+- macros: make `#[tokio::test]` append `#[test]` at the end of the attribute list ([#6497])
+
+[#6497]: https://github.com/tokio-rs/tokio/pull/6497
+
+# 2.2.0 (November 19th, 2023)
+
+### Changed
+
+- use `::core` qualified imports instead of `::std` inside `tokio::test` macro ([#5973])
+
+[#5973]: https://github.com/tokio-rs/tokio/pull/5973
+
+# 2.1.0 (April 25th, 2023)
+
+- macros: fix typo in `#[tokio::test]` docs ([#5636])
+- macros: make entrypoints more efficient ([#5621])
+
+[#5621]: https://github.com/tokio-rs/tokio/pull/5621
+[#5636]: https://github.com/tokio-rs/tokio/pull/5636
+
+# 2.0.0 (March 24th, 2023)
+
+This major release updates the dependency on the syn crate to 2.0.0, and
+increases the MSRV to 1.56.
+
+As part of this release, we are adopting a policy of depending on a specific minor
+release of tokio-macros. This prevents Tokio from being able to pull in many different
+versions of tokio-macros.
+
+- macros: update `syn` ([#5572])
+- macros: accept path as crate rename ([#5557])
+
+[#5572]: https://github.com/tokio-rs/tokio/pull/5572
+[#5557]: https://github.com/tokio-rs/tokio/pull/5557
+
 # 1.8.2 (November 30th, 2022)
 
 - fix a regression introduced in 1.8.1 ([#5244])

tokio-macros/Cargo.toml

@@ -4,9 +4,9 @@ name = "tokio-macros"
 # - Remove path dependencies
 # - Update CHANGELOG.md.
 # - Create "tokio-macros-1.x.y" git tag.
-version = "1.8.2"
-edition = "2018"
-rust-version = "1.49"
+version = "2.5.0"
+edition = "2021"
+rust-version = "1.70"
 authors = ["Tokio Contributors <[email protected]>"]
 license = "MIT"
 repository = "https://github.com/tokio-rs/tokio"
@@ -22,9 +22,9 @@ proc-macro = true
 [features]
 
 [dependencies]
-proc-macro2 = "1.0.7"
+proc-macro2 = "1.0.60"
 quote = "1"
-syn = { version = "1.0.56", features = ["full"] }
+syn = { version = "2.0", features = ["full"] }
 
 [dev-dependencies]
 tokio = { version = "1.0.0", path = "../tokio", features = ["full"] }

tokio-macros/LICENSE

@@ -1,32 +1,7 @@
-Copyright (c) 2023 Tokio Contributors
-
-Permission is hereby granted, free of charge, to any
-person obtaining a copy of this software and associated
-documentation files (the "Software"), to deal in the
-Software without restriction, including without
-limitation the rights to use, copy, modify, merge,
-publish, distribute, sublicense, and/or sell copies of
-the Software, and to permit persons to whom the Software
-is furnished to do so, subject to the following
-conditions:
-
-The above copyright notice and this permission notice
-shall be included in all copies or substantial portions
-of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
-ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
-TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
-PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
-SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
-OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
-IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-DEALINGS IN THE SOFTWARE.
-
-The MIT License (MIT)
+MIT License
 
 Copyright (c) 2019 Yoshua Wuyts
+Copyright (c) Tokio Contributors
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

tokio-macros/src/entry.rs

@@ -1,10 +1,10 @@
-use proc_macro::TokenStream;
-use proc_macro2::{Ident, Span};
+use proc_macro2::{Span, TokenStream, TokenTree};
 use quote::{quote, quote_spanned, ToTokens};
-use syn::parse::Parser;
+use syn::parse::{Parse, ParseStream, Parser};
+use syn::{braced, Attribute, Ident, Path, Signature, Visibility};
 
 // syn::AttributeArgs does not implement syn::Parse
-type AttributeArgs = syn::punctuated::Punctuated<syn::NestedMeta, syn::Token![,]>;
+type AttributeArgs = syn::punctuated::Punctuated<syn::Meta, syn::Token![,]>;
 
 #[derive(Clone, Copy, PartialEq)]
 enum RuntimeFlavor {
@@ -20,7 +20,32 @@ impl RuntimeFlavor {
             "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 `{}`. The runtime flavors are `current_thread` and `multi_thread`.", s)),
+            _ => Err(format!("No such runtime flavor `{s}`. The runtime flavors are `current_thread` and `multi_thread`.")),
+        }
+    }
+}
+
+#[derive(Clone, Copy, PartialEq)]
+enum UnhandledPanic {
+    Ignore,
+    ShutdownRuntime,
+}
+
+impl UnhandledPanic {
+    fn from_str(s: &str) -> Result<UnhandledPanic, String> {
+        match s {
+            "ignore" => Ok(UnhandledPanic::Ignore),
+            "shutdown_runtime" => Ok(UnhandledPanic::ShutdownRuntime),
+            _ => Err(format!("No such unhandled panic behavior `{s}`. The unhandled panic behaviors are `ignore` and `shutdown_runtime`.")),
+        }
+    }
+
+    fn into_tokens(self, crate_path: &TokenStream) -> TokenStream {
+        match self {
+            UnhandledPanic::Ignore => quote! { #crate_path::runtime::UnhandledPanic::Ignore },
+            UnhandledPanic::ShutdownRuntime => {
+                quote! { #crate_path::runtime::UnhandledPanic::ShutdownRuntime }
+            }
         }
     }
 }
@@ -29,7 +54,8 @@ struct FinalConfig {
     flavor: RuntimeFlavor,
     worker_threads: Option<usize>,
     start_paused: Option<bool>,
-    crate_name: Option<String>,
+    crate_name: Option<Path>,
+    unhandled_panic: Option<UnhandledPanic>,
 }
 
 /// Config used in case of the attribute not being able to build a valid config
@@ -38,6 +64,7 @@ const DEFAULT_ERROR_CONFIG: FinalConfig = FinalConfig {
     worker_threads: None,
     start_paused: None,
     crate_name: None,
+    unhandled_panic: None,
 };
 
 struct Configuration {
@@ -47,7 +74,8 @@ struct Configuration {
     worker_threads: Option<(usize, Span)>,
     start_paused: Option<(bool, Span)>,
     is_test: bool,
-    crate_name: Option<String>,
+    crate_name: Option<Path>,
+    unhandled_panic: Option<(UnhandledPanic, Span)>,
 }
 
 impl Configuration {
@@ -63,6 +91,7 @@ impl Configuration {
             start_paused: None,
             is_test,
             crate_name: None,
+            unhandled_panic: None,
         }
     }
 
@@ -112,8 +141,27 @@ impl Configuration {
         if self.crate_name.is_some() {
             return Err(syn::Error::new(span, "`crate` set multiple times."));
         }
-        let name_ident = parse_ident(name, span, "crate")?;
-        self.crate_name = Some(name_ident.to_string());
+        let name_path = parse_path(name, span, "crate")?;
+        self.crate_name = Some(name_path);
+        Ok(())
+    }
+
+    fn set_unhandled_panic(
+        &mut self,
+        unhandled_panic: syn::Lit,
+        span: Span,
+    ) -> Result<(), syn::Error> {
+        if self.unhandled_panic.is_some() {
+            return Err(syn::Error::new(
+                span,
+                "`unhandled_panic` set multiple times.",
+            ));
+        }
+
+        let unhandled_panic = parse_string(unhandled_panic, span, "unhandled_panic")?;
+        let unhandled_panic =
+            UnhandledPanic::from_str(&unhandled_panic).map_err(|err| syn::Error::new(span, err))?;
+        self.unhandled_panic = Some((unhandled_panic, span));
         Ok(())
     }
 
@@ -126,22 +174,22 @@ impl Configuration {
     }
 
     fn build(&self) -> Result<FinalConfig, syn::Error> {
-        let flavor = self.flavor.unwrap_or(self.default_flavor);
-        use RuntimeFlavor::*;
+        use RuntimeFlavor as F;
 
+        let flavor = self.flavor.unwrap_or(self.default_flavor);
         let worker_threads = match (flavor, self.worker_threads) {
-            (CurrentThread, Some((_, worker_threads_span))) => {
+            (F::CurrentThread, 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));
             }
-            (CurrentThread, None) => None,
-            (Threaded, worker_threads) if self.rt_multi_thread_available => {
+            (F::CurrentThread, None) => None,
+            (F::Threaded, worker_threads) if self.rt_multi_thread_available => {
                 worker_threads.map(|(val, _span)| val)
             }
-            (Threaded, _) => {
+            (F::Threaded, _) => {
                 let msg = if self.flavor.is_none() {
                     "The default runtime flavor is `multi_thread`, but the `rt-multi-thread` feature is disabled."
                 } else {
@@ -152,14 +200,26 @@ impl Configuration {
         };
 
         let start_paused = match (flavor, self.start_paused) {
-            (Threaded, Some((_, start_paused_span))) => {
+            (F::Threaded, Some((_, start_paused_span))) => {
                 let msg = format!(
                     "The `start_paused` option requires the `current_thread` runtime flavor. Use `#[{}(flavor = \"current_thread\")]`",
                     self.macro_name(),
                 );
                 return Err(syn::Error::new(start_paused_span, msg));
             }
-            (CurrentThread, Some((start_paused, _))) => Some(start_paused),
+            (F::CurrentThread, Some((start_paused, _))) => Some(start_paused),
+            (_, None) => None,
+        };
+
+        let unhandled_panic = match (flavor, self.unhandled_panic) {
+            (F::Threaded, Some((_, unhandled_panic_span))) => {
+                let msg = format!(
+                    "The `unhandled_panic` option requires the `current_thread` runtime flavor. Use `#[{}(flavor = \"current_thread\")]`",
+                    self.macro_name(),
+                );
+                return Err(syn::Error::new(unhandled_panic_span, msg));
+            }
+            (F::CurrentThread, Some((unhandled_panic, _))) => Some(unhandled_panic),
             (_, None) => None,
         };
 
@@ -168,6 +228,7 @@ impl Configuration {
             flavor,
             worker_threads,
             start_paused,
+            unhandled_panic,
         })
     }
 }
@@ -178,12 +239,12 @@ fn parse_int(int: syn::Lit, span: Span, field: &str) -> Result<usize, syn::Error
             Ok(value) => Ok(value),
             Err(e) => Err(syn::Error::new(
                 span,
-                format!("Failed to parse value of `{}` as integer: {}", field, e),
+                format!("Failed to parse value of `{field}` as integer: {e}"),
             )),
         },
         _ => Err(syn::Error::new(
             span,
-            format!("Failed to parse value of `{}` as integer.", field),
+            format!("Failed to parse value of `{field}` as integer."),
         )),
     }
 }
@@ -194,28 +255,27 @@ fn parse_string(int: syn::Lit, span: Span, field: &str) -> Result<String, syn::E
         syn::Lit::Verbatim(s) => Ok(s.to_string()),
         _ => Err(syn::Error::new(
             span,
-            format!("Failed to parse value of `{}` as string.", field),
+            format!("Failed to parse value of `{field}` as string."),
         )),
     }
 }
 
-fn parse_ident(lit: syn::Lit, span: Span, field: &str) -> Result<Ident, syn::Error> {
+fn parse_path(lit: syn::Lit, span: Span, field: &str) -> Result<Path, syn::Error> {
     match lit {
         syn::Lit::Str(s) => {
             let err = syn::Error::new(
                 span,
                 format!(
-                    "Failed to parse value of `{}` as ident: \"{}\"",
+                    "Failed to parse value of `{}` as path: \"{}\"",
                     field,
                     s.value()
                 ),
             );
-            let path = s.parse::<syn::Path>().map_err(|_| err.clone())?;
-            path.get_ident().cloned().ok_or(err)
+            s.parse::<syn::Path>().map_err(|_| err.clone())
         }
         _ => Err(syn::Error::new(
             span,
-            format!("Failed to parse value of `{}` as ident.", field),
+            format!("Failed to parse value of `{field}` as path."),
         )),
     }
 }
@@ -225,13 +285,13 @@ fn parse_bool(bool: syn::Lit, span: Span, field: &str) -> Result<bool, syn::Erro
         syn::Lit::Bool(b) => Ok(b.value),
         _ => Err(syn::Error::new(
             span,
-            format!("Failed to parse value of `{}` as bool.", field),
+            format!("Failed to parse value of `{field}` as bool."),
         )),
     }
 }
 
 fn build_config(
-    input: syn::ItemFn,
+    input: &ItemFn,
     args: AttributeArgs,
     is_test: bool,
     rt_multi_thread: bool,
@@ -246,7 +306,7 @@ fn build_config(
 
     for arg in args {
         match arg {
-            syn::NestedMeta::Meta(syn::Meta::NameValue(namevalue)) => {
+            syn::Meta::NameValue(namevalue) => {
                 let ident = namevalue
                     .path
                     .get_ident()
@@ -255,45 +315,40 @@ fn build_config(
                     })?
                     .to_string()
                     .to_lowercase();
+                let lit = match &namevalue.value {
+                    syn::Expr::Lit(syn::ExprLit { lit, .. }) => lit,
+                    expr => return Err(syn::Error::new_spanned(expr, "Must be a literal")),
+                };
                 match ident.as_str() {
                     "worker_threads" => {
-                        config.set_worker_threads(
-                            namevalue.lit.clone(),
-                            syn::spanned::Spanned::span(&namevalue.lit),
-                        )?;
+                        config.set_worker_threads(lit.clone(), syn::spanned::Spanned::span(lit))?;
                     }
                     "flavor" => {
-                        config.set_flavor(
-                            namevalue.lit.clone(),
-                            syn::spanned::Spanned::span(&namevalue.lit),
-                        )?;
+                        config.set_flavor(lit.clone(), syn::spanned::Spanned::span(lit))?;
                     }
                     "start_paused" => {
-                        config.set_start_paused(
-                            namevalue.lit.clone(),
-                            syn::spanned::Spanned::span(&namevalue.lit),
-                        )?;
+                        config.set_start_paused(lit.clone(), syn::spanned::Spanned::span(lit))?;
                     }
                     "core_threads" => {
                         let msg = "Attribute `core_threads` is renamed to `worker_threads`";
                         return Err(syn::Error::new_spanned(namevalue, msg));
                     }
                     "crate" => {
-                        config.set_crate_name(
-                            namevalue.lit.clone(),
-                            syn::spanned::Spanned::span(&namevalue.lit),
-                        )?;
+                        config.set_crate_name(lit.clone(), syn::spanned::Spanned::span(lit))?;
+                    }
+                    "unhandled_panic" => {
+                        config
+                            .set_unhandled_panic(lit.clone(), syn::spanned::Spanned::span(lit))?;
                     }
                     name => {
                         let msg = format!(
-                            "Unknown attribute {} is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`",
-                            name,
+                            "Unknown attribute {name} is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`, `unhandled_panic`",
                         );
                         return Err(syn::Error::new_spanned(namevalue, msg));
                     }
                 }
             }
-            syn::NestedMeta::Meta(syn::Meta::Path(path)) => {
+            syn::Meta::Path(path) => {
                 let name = path
                     .get_ident()
                     .ok_or_else(|| syn::Error::new_spanned(&path, "Must have specified ident"))?
@@ -302,21 +357,19 @@ fn build_config(
                 let msg = match name.as_str() {
                     "threaded_scheduler" | "multi_thread" => {
                         format!(
-                            "Set the runtime flavor with #[{}(flavor = \"multi_thread\")].",
-                            macro_name
+                            "Set the runtime flavor with #[{macro_name}(flavor = \"multi_thread\")]."
                         )
                     }
                     "basic_scheduler" | "current_thread" | "single_threaded" => {
                         format!(
-                            "Set the runtime flavor with #[{}(flavor = \"current_thread\")].",
-                            macro_name
+                            "Set the runtime flavor with #[{macro_name}(flavor = \"current_thread\")]."
                         )
                     }
-                    "flavor" | "worker_threads" | "start_paused" => {
-                        format!("The `{}` attribute requires an argument.", name)
+                    "flavor" | "worker_threads" | "start_paused" | "crate" | "unhandled_panic" => {
+                        format!("The `{name}` attribute requires an argument.")
                     }
                     name => {
-                        format!("Unknown attribute {} is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`", name)
+                        format!("Unknown attribute {name} is specified; expected one of: `flavor`, `worker_threads`, `start_paused`, `crate`, `unhandled_panic`.")
                     }
                 };
                 return Err(syn::Error::new_spanned(path, msg));
@@ -333,18 +386,13 @@ fn build_config(
     config.build()
 }
 
-fn parse_knobs(mut input: syn::ItemFn, is_test: bool, config: FinalConfig) -> TokenStream {
+fn parse_knobs(mut input: ItemFn, is_test: bool, config: FinalConfig) -> TokenStream {
     input.sig.asyncness = None;
 
     // If type mismatch occurs, the current rustc points to the last statement.
     let (last_stmt_start_span, last_stmt_end_span) = {
-        let mut last_stmt = input
-            .block
-            .stmts
-            .last()
-            .map(ToTokens::into_token_stream)
-            .unwrap_or_default()
-            .into_iter();
+        let mut last_stmt = input.stmts.last().cloned().unwrap_or_default().into_iter();
+
         // `Span` on stable Rust has a limitation that only points to the first
         // token, not the whole tokens. We can work around this limitation by
         // using the first/last span of the tokens like
@@ -354,26 +402,31 @@ fn parse_knobs(mut input: syn::ItemFn, is_test: bool, config: FinalConfig) -> To
         (start, end)
     };
 
-    let crate_name = config.crate_name.as_deref().unwrap_or("tokio");
-
-    let crate_ident = Ident::new(crate_name, last_stmt_start_span);
+    let crate_path = config
+        .crate_name
+        .map(ToTokens::into_token_stream)
+        .unwrap_or_else(|| Ident::new("tokio", last_stmt_start_span).into_token_stream());
 
     let mut rt = match config.flavor {
         RuntimeFlavor::CurrentThread => quote_spanned! {last_stmt_start_span=>
-            #crate_ident::runtime::Builder::new_current_thread()
+            #crate_path::runtime::Builder::new_current_thread()
         },
         RuntimeFlavor::Threaded => quote_spanned! {last_stmt_start_span=>
-            #crate_ident::runtime::Builder::new_multi_thread()
+            #crate_path::runtime::Builder::new_multi_thread()
         },
     };
     if let Some(v) = config.worker_threads {
-        rt = quote! { #rt.worker_threads(#v) };
+        rt = quote_spanned! {last_stmt_start_span=> #rt.worker_threads(#v) };
     }
     if let Some(v) = config.start_paused {
-        rt = quote! { #rt.start_paused(#v) };
+        rt = quote_spanned! {last_stmt_start_span=> #rt.start_paused(#v) };
+    }
+    if let Some(v) = config.unhandled_panic {
+        let unhandled_panic = v.into_tokens(&crate_path);
+        rt = quote_spanned! {last_stmt_start_span=> #rt.unhandled_panic(#unhandled_panic) };
     }
 
-    let header = if is_test {
+    let generated_attrs = if is_test {
         quote! {
             #[::core::prelude::v1::test]
         }
@@ -381,11 +434,10 @@ fn parse_knobs(mut input: syn::ItemFn, is_test: bool, config: FinalConfig) -> To
         quote! {}
     };
 
-    let body = &input.block;
-    let brace_token = input.block.brace_token;
     let body_ident = quote! { body };
-    let block_expr = quote_spanned! {last_stmt_end_span=>
-        #[allow(clippy::expect_used, clippy::diverging_sub_expression)]
+    // 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)]
         {
             return #rt
                 .enable_all()
@@ -395,6 +447,8 @@ fn parse_knobs(mut input: syn::ItemFn, is_test: bool, config: FinalConfig) -> To
         }
     };
 
+    let body = input.body();
+
     // For test functions pin the body to the stack and use `Pin<&mut dyn
     // Future>` to reduce the amount of `Runtime::block_on` (and related
     // functions) copies we generate during compilation due to the generic
@@ -414,8 +468,8 @@ fn parse_knobs(mut input: syn::ItemFn, is_test: bool, config: FinalConfig) -> To
         };
         quote! {
             let body = async #body;
-            #crate_ident::pin!(body);
-            let body: ::std::pin::Pin<&mut dyn ::std::future::Future<Output = #output_type>> = body;
+            #crate_path::pin!(body);
+            let body: ::core::pin::Pin<&mut dyn ::core::future::Future<Output = #output_type>> = body;
         }
     } else {
         quote! {
@@ -423,34 +477,19 @@ fn parse_knobs(mut input: syn::ItemFn, is_test: bool, config: FinalConfig) -> To
         }
     };
 
-    input.block = syn::parse2(quote! {
-        {
-            #body
-            #block_expr
-        }
-    })
-    .expect("Parsing failure");
-    input.block.brace_token = brace_token;
-
-    let result = quote! {
-        #header
-        #input
-    };
-
-    result.into()
+    input.into_tokens(generated_attrs, body, last_block)
 }
 
 fn token_stream_with_error(mut tokens: TokenStream, error: syn::Error) -> TokenStream {
-    tokens.extend(TokenStream::from(error.into_compile_error()));
+    tokens.extend(error.into_compile_error());
     tokens
 }
 
-#[cfg(not(test))] // Work around for rust-lang/rust#62127
 pub(crate) fn main(args: TokenStream, item: TokenStream, rt_multi_thread: bool) -> TokenStream {
     // If any of the steps for this macro fail, we still want to expand to an item that is as close
     // to the expected output as possible. This helps out IDEs such that completions and other
     // related features keep working.
-    let input: syn::ItemFn = match syn::parse(item.clone()) {
+    let input: ItemFn = match syn::parse2(item.clone()) {
         Ok(it) => it,
         Err(e) => return token_stream_with_error(item, e),
     };
@@ -460,8 +499,8 @@ pub(crate) fn main(args: TokenStream, item: TokenStream, rt_multi_thread: bool)
         Err(syn::Error::new_spanned(&input.sig.ident, msg))
     } else {
         AttributeArgs::parse_terminated
-            .parse(args)
-            .and_then(|args| build_config(input.clone(), args, false, rt_multi_thread))
+            .parse2(args)
+            .and_then(|args| build_config(&input, args, false, rt_multi_thread))
     };
 
     match config {
@@ -470,21 +509,50 @@ pub(crate) fn main(args: TokenStream, item: TokenStream, rt_multi_thread: bool)
     }
 }
 
+// Check whether given attribute is a test attribute of forms:
+// * `#[test]`
+// * `#[core::prelude::*::test]` or `#[::core::prelude::*::test]`
+// * `#[std::prelude::*::test]` or `#[::std::prelude::*::test]`
+fn is_test_attribute(attr: &Attribute) -> bool {
+    let path = match &attr.meta {
+        syn::Meta::Path(path) => path,
+        _ => return false,
+    };
+    let candidates = [
+        ["core", "prelude", "*", "test"],
+        ["std", "prelude", "*", "test"],
+    ];
+    if path.leading_colon.is_none()
+        && path.segments.len() == 1
+        && path.segments[0].arguments.is_none()
+        && path.segments[0].ident == "test"
+    {
+        return true;
+    } else if path.segments.len() != candidates[0].len() {
+        return false;
+    }
+    candidates.into_iter().any(|segments| {
+        path.segments.iter().zip(segments).all(|(segment, path)| {
+            segment.arguments.is_none() && (path == "*" || segment.ident == path)
+        })
+    })
+}
+
 pub(crate) fn test(args: TokenStream, item: TokenStream, rt_multi_thread: bool) -> TokenStream {
     // If any of the steps for this macro fail, we still want to expand to an item that is as close
     // to the expected output as possible. This helps out IDEs such that completions and other
     // related features keep working.
-    let input: syn::ItemFn = match syn::parse(item.clone()) {
+    let input: ItemFn = match syn::parse2(item.clone()) {
         Ok(it) => it,
         Err(e) => return token_stream_with_error(item, e),
     };
-    let config = if let Some(attr) = input.attrs.iter().find(|attr| attr.path.is_ident("test")) {
-        let msg = "second test attribute is supplied";
+    let config = if let Some(attr) = input.attrs().find(|attr| is_test_attribute(attr)) {
+        let msg = "second test attribute is supplied, consider removing or changing the order of your test attributes";
         Err(syn::Error::new_spanned(attr, msg))
     } else {
         AttributeArgs::parse_terminated
-            .parse(args)
-            .and_then(|args| build_config(input.clone(), args, true, rt_multi_thread))
+            .parse2(args)
+            .and_then(|args| build_config(&input, args, true, rt_multi_thread))
     };
 
     match config {
@@ -492,3 +560,128 @@ pub(crate) fn test(args: TokenStream, item: TokenStream, rt_multi_thread: bool)
         Err(e) => token_stream_with_error(parse_knobs(input, true, DEFAULT_ERROR_CONFIG), e),
     }
 }
+
+struct ItemFn {
+    outer_attrs: Vec<Attribute>,
+    vis: Visibility,
+    sig: Signature,
+    brace_token: syn::token::Brace,
+    inner_attrs: Vec<Attribute>,
+    stmts: Vec<proc_macro2::TokenStream>,
+}
+
+impl ItemFn {
+    /// Access all attributes of the function item.
+    fn attrs(&self) -> impl Iterator<Item = &Attribute> {
+        self.outer_attrs.iter().chain(self.inner_attrs.iter())
+    }
+
+    /// Get the body of the function item in a manner so that it can be
+    /// conveniently used with the `quote!` macro.
+    fn body(&self) -> Body<'_> {
+        Body {
+            brace_token: self.brace_token,
+            stmts: &self.stmts,
+        }
+    }
+
+    /// Convert our local function item into a token stream.
+    fn into_tokens(
+        self,
+        generated_attrs: proc_macro2::TokenStream,
+        body: proc_macro2::TokenStream,
+        last_block: proc_macro2::TokenStream,
+    ) -> TokenStream {
+        let mut tokens = proc_macro2::TokenStream::new();
+        // Outer attributes are simply streamed as-is.
+        for attr in self.outer_attrs {
+            attr.to_tokens(&mut tokens);
+        }
+
+        // Inner attributes require extra care, since they're not supported on
+        // blocks (which is what we're expanded into) we instead lift them
+        // outside of the function. This matches the behavior of `syn`.
+        for mut attr in self.inner_attrs {
+            attr.style = syn::AttrStyle::Outer;
+            attr.to_tokens(&mut tokens);
+        }
+
+        // Add generated macros at the end, so macros processed later are aware of them.
+        generated_attrs.to_tokens(&mut tokens);
+
+        self.vis.to_tokens(&mut tokens);
+        self.sig.to_tokens(&mut tokens);
+
+        self.brace_token.surround(&mut tokens, |tokens| {
+            body.to_tokens(tokens);
+            last_block.to_tokens(tokens);
+        });
+
+        tokens
+    }
+}
+
+impl Parse for ItemFn {
+    #[inline]
+    fn parse(input: ParseStream<'_>) -> syn::Result<Self> {
+        // This parse implementation has been largely lifted from `syn`, with
+        // the exception of:
+        // * We don't have access to the plumbing necessary to parse inner
+        //   attributes in-place.
+        // * We do our own statements parsing to avoid recursively parsing
+        //   entire statements and only look for the parts we're interested in.
+
+        let outer_attrs = input.call(Attribute::parse_outer)?;
+        let vis: Visibility = input.parse()?;
+        let sig: Signature = input.parse()?;
+
+        let content;
+        let brace_token = braced!(content in input);
+        let inner_attrs = Attribute::parse_inner(&content)?;
+
+        let mut buf = proc_macro2::TokenStream::new();
+        let mut stmts = Vec::new();
+
+        while !content.is_empty() {
+            if let Some(semi) = content.parse::<Option<syn::Token![;]>>()? {
+                semi.to_tokens(&mut buf);
+                stmts.push(buf);
+                buf = proc_macro2::TokenStream::new();
+                continue;
+            }
+
+            // Parse a single token tree and extend our current buffer with it.
+            // This avoids parsing the entire content of the sub-tree.
+            buf.extend([content.parse::<TokenTree>()?]);
+        }
+
+        if !buf.is_empty() {
+            stmts.push(buf);
+        }
+
+        Ok(Self {
+            outer_attrs,
+            vis,
+            sig,
+            brace_token,
+            inner_attrs,
+            stmts,
+        })
+    }
+}
+
+struct Body<'a> {
+    brace_token: syn::token::Brace,
+    // Statements, with terminating `;`.
+    stmts: &'a [TokenStream],
+}
+
+impl ToTokens for Body<'_> {
+    fn to_tokens(&self, tokens: &mut proc_macro2::TokenStream) {
+        self.brace_token.surround(tokens, |tokens| {
+            for stmt in self.stmts {
+                stmt.to_tokens(tokens);
+            }
+        });
+    }
+}

tokio-macros/src/lib.rs

@@ -1,3 +1,4 @@
+#![allow(unknown_lints, unexpected_cfgs)]
 #![allow(clippy::needless_doctest_main)]
 #![warn(
     missing_debug_implementations,
@@ -39,6 +40,13 @@ use proc_macro::TokenStream;
 /// function is called often, it is preferable to create the runtime using the
 /// runtime builder so the runtime can be reused across calls.
 ///
+/// # Non-worker async function
+///
+/// Note that the async function marked with this macro does not run as a
+/// worker. The expectation is that other tasks are spawned by the function here.
+/// Awaiting on other futures from the function provided here will not
+/// perform as fast as those spawned as workers.
+///
 /// # Multi-threaded runtime
 ///
 /// To use the multi-threaded runtime, the macro can be configured using
@@ -194,15 +202,62 @@ use proc_macro::TokenStream;
 ///         })
 /// }
 /// ```
+///
+/// ### Configure unhandled panic behavior
+///
+/// Available options are `shutdown_runtime` and `ignore`. For more details, see
+/// [`Builder::unhandled_panic`].
+///
+/// This option is only compatible with the `current_thread` runtime.
+///
+/// ```no_run
+/// # #![allow(unknown_lints, unexpected_cfgs)]
+/// #[cfg(tokio_unstable)]
+/// #[tokio::main(flavor = "current_thread", unhandled_panic = "shutdown_runtime")]
+/// async fn main() {
+///     let _ = tokio::spawn(async {
+///         panic!("This panic will shutdown the runtime.");
+///     }).await;
+/// }
+/// # #[cfg(not(tokio_unstable))]
+/// # fn main() { }
+/// ```
+///
+/// Equivalent code not using `#[tokio::main]`
+///
+/// ```no_run
+/// # #![allow(unknown_lints, unexpected_cfgs)]
+/// #[cfg(tokio_unstable)]
+/// fn main() {
+///     tokio::runtime::Builder::new_current_thread()
+///         .enable_all()
+///         .unhandled_panic(UnhandledPanic::ShutdownRuntime)
+///         .build()
+///         .unwrap()
+///         .block_on(async {
+///             let _ = tokio::spawn(async {
+///                 panic!("This panic will shutdown the runtime.");
+///             }).await;
+///         })
+/// }
+/// # #[cfg(not(tokio_unstable))]
+/// # fn main() { }
+/// ```
+///
+/// **Note**: This option depends on Tokio's [unstable API][unstable]. See [the
+/// documentation on unstable features][unstable] for details on how to enable
+/// Tokio's unstable features.
+///
+/// [`Builder::unhandled_panic`]: ../tokio/runtime/struct.Builder.html#method.unhandled_panic
+/// [unstable]: ../tokio/index.html#unstable-features
 #[proc_macro_attribute]
-#[cfg(not(test))] // Work around for rust-lang/rust#62127
 pub fn main(args: TokenStream, item: TokenStream) -> TokenStream {
-    entry::main(args, item, true)
+    entry::main(args.into(), item.into(), true).into()
 }
 
 /// Marks async function to be executed by selected runtime. This macro helps set up a `Runtime`
 /// without requiring the user to use [Runtime](../tokio/runtime/struct.Runtime.html) or
-/// [Builder](../tokio/runtime/struct.builder.html) directly.
+/// [Builder](../tokio/runtime/struct.Builder.html) directly.
 ///
 /// ## Function arguments:
 ///
@@ -260,9 +315,8 @@ pub fn main(args: TokenStream, item: TokenStream) -> TokenStream {
 /// }
 /// ```
 #[proc_macro_attribute]
-#[cfg(not(test))] // Work around for rust-lang/rust#62127
 pub fn main_rt(args: TokenStream, item: TokenStream) -> TokenStream {
-    entry::main(args, item, false)
+    entry::main(args.into(), item.into(), false).into()
 }
 
 /// Marks async function to be executed by runtime, suitable to test environment.
@@ -288,8 +342,7 @@ pub fn main_rt(args: TokenStream, item: TokenStream) -> TokenStream {
 /// ```
 ///
 /// The `worker_threads` option configures the number of worker threads, and
-/// defaults to the number of cpus on the system. This is the default
-/// flavor.
+/// defaults to the number of cpus on the system.
 ///
 /// Note: The multi-threaded runtime requires the `rt-multi-thread` feature
 /// flag.
@@ -359,7 +412,7 @@ pub fn main_rt(args: TokenStream, item: TokenStream) -> TokenStream {
 /// ### Set number of worker threads
 ///
 /// ```no_run
-/// #[tokio::test(flavor ="multi_thread", worker_threads = 2)]
+/// #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 /// async fn my_test() {
 ///     assert!(true);
 /// }
@@ -418,9 +471,58 @@ pub fn main_rt(args: TokenStream, item: TokenStream) -> TokenStream {
 ///     println!("Hello world");
 /// }
 /// ```
+///
+/// ### Configure unhandled panic behavior
+///
+/// Available options are `shutdown_runtime` and `ignore`. For more details, see
+/// [`Builder::unhandled_panic`].
+///
+/// This option is only compatible with the `current_thread` runtime.
+///
+/// ```no_run
+/// # #![allow(unknown_lints, unexpected_cfgs)]
+/// #[cfg(tokio_unstable)]
+/// #[tokio::test(flavor = "current_thread", unhandled_panic = "shutdown_runtime")]
+/// async fn my_test() {
+///     let _ = tokio::spawn(async {
+///         panic!("This panic will shutdown the runtime.");
+///     }).await;
+/// }
+/// # #[cfg(not(tokio_unstable))]
+/// # fn main() { }
+/// ```
+///
+/// Equivalent code not using `#[tokio::test]`
+///
+/// ```no_run
+/// # #![allow(unknown_lints, unexpected_cfgs)]
+/// #[cfg(tokio_unstable)]
+/// #[test]
+/// fn my_test() {
+///     tokio::runtime::Builder::new_current_thread()
+///         .enable_all()
+///         .unhandled_panic(UnhandledPanic::ShutdownRuntime)
+///         .build()
+///         .unwrap()
+///         .block_on(async {
+///             let _ = tokio::spawn(async {
+///                 panic!("This panic will shutdown the runtime.");
+///             }).await;
+///         })
+/// }
+/// # #[cfg(not(tokio_unstable))]
+/// # fn main() { }
+/// ```
+///
+/// **Note**: This option depends on Tokio's [unstable API][unstable]. See [the
+/// documentation on unstable features][unstable] for details on how to enable
+/// Tokio's unstable features.
+///
+/// [`Builder::unhandled_panic`]: ../tokio/runtime/struct.Builder.html#method.unhandled_panic
+/// [unstable]: ../tokio/index.html#unstable-features
 #[proc_macro_attribute]
 pub fn test(args: TokenStream, item: TokenStream) -> TokenStream {
-    entry::test(args, item, true)
+    entry::test(args.into(), item.into(), true).into()
 }
 
 /// Marks async function to be executed by runtime, suitable to test environment
@@ -435,7 +537,7 @@ pub fn test(args: TokenStream, item: TokenStream) -> TokenStream {
 /// ```
 #[proc_macro_attribute]
 pub fn test_rt(args: TokenStream, item: TokenStream) -> TokenStream {
-    entry::test(args, item, false)
+    entry::test(args.into(), item.into(), false).into()
 }
 
 /// Always fails with the error message below.

tokio-macros/src/select.rs

@@ -1,7 +1,7 @@
 use proc_macro::{TokenStream, TokenTree};
 use proc_macro2::Span;
 use quote::quote;
-use syn::Ident;
+use syn::{parse::Parser, Ident};
 
 pub(crate) fn declare_output_enum(input: TokenStream) -> TokenStream {
     // passed in is: `(_ _ _)` with one `_` per branch
@@ -11,7 +11,7 @@ pub(crate) fn declare_output_enum(input: TokenStream) -> TokenStream {
     };
 
     let variants = (0..branches)
-        .map(|num| Ident::new(&format!("_{}", num), Span::call_site()))
+        .map(|num| Ident::new(&format!("_{num}"), Span::call_site()))
         .collect::<Vec<_>>();
 
     // Use a bitfield to track which futures completed
@@ -46,7 +46,7 @@ pub(crate) fn clean_pattern_macro(input: TokenStream) -> TokenStream {
     // If this isn't a pattern, we return the token stream as-is. The select!
     // macro is using it in a location requiring a pattern, so an error will be
     // emitted there.
-    let mut input: syn::Pat = match syn::parse(input.clone()) {
+    let mut input: syn::Pat = match syn::Pat::parse_single.parse(input.clone()) {
         Ok(it) => it,
         Err(_) => return input,
     };
@@ -58,7 +58,6 @@ pub(crate) fn clean_pattern_macro(input: TokenStream) -> TokenStream {
 // Removes any occurrences of ref or mut in the provided pattern.
 fn clean_pattern(pat: &mut syn::Pat) {
     match pat {
-        syn::Pat::Box(_box) => {}
         syn::Pat::Lit(_literal) => {}
         syn::Pat::Macro(_macro) => {}
         syn::Pat::Path(_path) => {}
@@ -74,27 +73,27 @@ fn clean_pattern(pat: &mut syn::Pat) {
             }
         }
         syn::Pat::Or(or) => {
-            for case in or.cases.iter_mut() {
+            for case in &mut or.cases {
                 clean_pattern(case);
             }
         }
         syn::Pat::Slice(slice) => {
-            for elem in slice.elems.iter_mut() {
+            for elem in &mut slice.elems {
                 clean_pattern(elem);
             }
         }
         syn::Pat::Struct(struct_pat) => {
-            for field in struct_pat.fields.iter_mut() {
+            for field in &mut struct_pat.fields {
                 clean_pattern(&mut field.pat);
             }
         }
         syn::Pat::Tuple(tuple) => {
-            for elem in tuple.elems.iter_mut() {
+            for elem in &mut tuple.elems {
                 clean_pattern(elem);
             }
         }
         syn::Pat::TupleStruct(tuple) => {
-            for elem in tuple.pat.elems.iter_mut() {
+            for elem in &mut tuple.elems {
                 clean_pattern(elem);
             }
         }

tokio-stream/CHANGELOG.md

@@ -1,10 +1,70 @@
-# 0.1.12 (January 20, 2022)
+# 0.1.17 (December 6th, 2024)
+
+- deps: fix dev-dependency on tokio-test ([#6931], [#7019])
+- stream: fix link on `Peekable` ([#6861])
+- sync: fix `Stream` link in broadcast docs ([#6873])
+
+[#6861]: https://github.com/tokio-rs/tokio/pull/6861
+[#6873]: https://github.com/tokio-rs/tokio/pull/6873
+[#6931]: https://github.com/tokio-rs/tokio/pull/6931
+[#7019]: https://github.com/tokio-rs/tokio/pull/7019
+
+# 0.1.16 (September 5th, 2024)
+
+This release bumps the MSRV of tokio-stream to 1.70.
+
+- stream: add `next_many` and `poll_next_many` to `StreamMap` ([#6409])
+- stream: make stream adapters public ([#6658])
+- readme: add readme for tokio-stream ([#6456])
+
+[#6409]: https://github.com/tokio-rs/tokio/pull/6409
+[#6658]: https://github.com/tokio-rs/tokio/pull/6658
+[#6456]: https://github.com/tokio-rs/tokio/pull/6456
+
+# 0.1.15 (March 14th, 2024)
+
+This release bumps the MSRV of tokio-stream to 1.63.
+
+- docs: fix typo in argument name ([#6389])
+- docs: fix typo in peekable docs ([#6130])
+- docs: link to latest version of tokio-util docs ([#5694])
+- docs: typographic improvements ([#6262])
+- stream: add `StreamExt::peekable` ([#6095])
+
+[#5694]: https://github.com/tokio-rs/tokio/pull/5694
+[#6095]: https://github.com/tokio-rs/tokio/pull/6095
+[#6130]: https://github.com/tokio-rs/tokio/pull/6130
+[#6262]: https://github.com/tokio-rs/tokio/pull/6262
+[#6389]: https://github.com/tokio-rs/tokio/pull/6389
+
+# 0.1.14 (April 26th, 2023)
+
+This bugfix release bumps the minimum version of Tokio to 1.15, which is
+necessary for `timeout_repeating` to compile. ([#5657])
+
+[#5657]: https://github.com/tokio-rs/tokio/pull/5657
+
+# 0.1.13 (April 25th, 2023)
+
+This release bumps the MSRV of tokio-stream to 1.56.
+
+- stream: add "full" feature flag ([#5639])
+- stream: add `StreamExt::timeout_repeating` ([#5577])
+- stream: add `StreamNotifyClose` ([#4851])
+
+[#4851]: https://github.com/tokio-rs/tokio/pull/4851
+[#5577]: https://github.com/tokio-rs/tokio/pull/5577
+[#5639]: https://github.com/tokio-rs/tokio/pull/5639
+
+# 0.1.12 (January 20, 2023)
 
 - time: remove `Unpin` bound on `Throttle` methods ([#5105])
 - time: document that `throttle` operates on ms granularity ([#5101])
+- sync: add `WatchStream::from_changes` ([#5432])
 
 [#5105]: https://github.com/tokio-rs/tokio/pull/5105
 [#5101]: https://github.com/tokio-rs/tokio/pull/5101
+[#5432]: https://github.com/tokio-rs/tokio/pull/5432
 
 # 0.1.11 (October 11, 2022)
 

tokio-stream/Cargo.toml

@@ -4,9 +4,9 @@ name = "tokio-stream"
 # - Remove path dependencies
 # - Update CHANGELOG.md.
 # - Create "tokio-stream-0.1.x" git tag.
-version = "0.1.12"
-edition = "2018"
-rust-version = "1.49"
+version = "0.1.17"
+edition = "2021"
+rust-version = "1.70"
 authors = ["Tokio Contributors <[email protected]>"]
 license = "MIT"
 repository = "https://github.com/tokio-rs/tokio"
@@ -18,6 +18,16 @@ categories = ["asynchronous"]
 
 [features]
 default = ["time"]
+
+full = [
+    "time",
+    "net",
+    "io-util",
+    "fs",
+    "sync",
+    "signal"
+]
+
 time = ["tokio/time"]
 net = ["tokio/net"]
 io-util = ["tokio/io-util"]
@@ -27,15 +37,15 @@ signal = ["tokio/signal"]
 
 [dependencies]
 futures-core = { version = "0.3.0" }
-pin-project-lite = "0.2.0"
-tokio = { version = "1.8.0", path = "../tokio", features = ["sync"] }
+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 }
 
 [dev-dependencies]
 tokio = { version = "1.2.0", path = "../tokio", features = ["full", "test-util"] }
 async-stream = "0.3"
 parking_lot = "0.12.0"
-tokio-test = { path = "../tokio-test" }
+tokio-test = { version = "0.4", path = "../tokio-test" }
 futures = { version = "0.3", default-features = false }
 
 [package.metadata.docs.rs]

tokio-stream/LICENSE

@@ -1,25 +1,21 @@
-Copyright (c) 2023 Tokio Contributors
+MIT License
 
-Permission is hereby granted, free of charge, to any
-person obtaining a copy of this software and associated
-documentation files (the "Software"), to deal in the
-Software without restriction, including without
-limitation the rights to use, copy, modify, merge,
-publish, distribute, sublicense, and/or sell copies of
-the Software, and to permit persons to whom the Software
-is furnished to do so, subject to the following
-conditions:
+Copyright (c) Tokio Contributors
 
-The above copyright notice and this permission notice
-shall be included in all copies or substantial portions
-of the Software.
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
 
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
-ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
-TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
-PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
-SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
-OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
-IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-DEALINGS IN THE SOFTWARE.
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

tokio-stream/README.md

@@ -0,0 +1,13 @@
+# tokio-stream
+
+Utilities to work with `Stream` and `tokio`.
+
+## License
+
+This project is licensed under the [MIT license](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
+terms or conditions.

tokio-stream/fuzz/Cargo.toml

@@ -2,7 +2,7 @@
 name = "tokio-stream-fuzz"
 version = "0.0.0"
 publish = false
-edition = "2018"
+edition = "2021"
 
 [package.metadata]
 cargo-fuzz = true

tokio-stream/fuzz/fuzz_targets/fuzz_stream_map.rs

@@ -3,17 +3,8 @@
 use libfuzzer_sys::fuzz_target;
 use std::pin::Pin;
 
-use tokio_stream::{self as stream, pending, Stream, StreamExt, StreamMap};
-use tokio_test::{assert_ok, assert_pending, assert_ready, task};
-
-macro_rules! assert_ready_some {
-    ($($t:tt)*) => {
-        match assert_ready!($($t)*) {
-            Some(v) => v,
-            None => panic!("expected `Some`, got `None`"),
-        }
-    };
-}
+use tokio_stream::{self as stream, Stream, StreamMap};
+use tokio_test::{assert_pending, assert_ready, task};
 
 macro_rules! assert_ready_none {
     ($($t:tt)*) => {
@@ -28,7 +19,7 @@ fn pin_box<T: Stream<Item = U> + 'static, U>(s: T) -> Pin<Box<dyn Stream<Item =
     Box::pin(s)
 }
 
-fuzz_target!(|data: &[u8]| {
+fuzz_target!(|data: [bool; 64]| {
     use std::task::{Context, Poll};
 
     struct DidPoll<T> {
@@ -45,11 +36,12 @@ fuzz_target!(|data: &[u8]| {
         }
     }
 
-    for _ in 0..10 {
+    // Try the test with each possible length.
+    for len in 0..data.len() {
         let mut map = task::spawn(StreamMap::new());
         let mut expect = 0;
 
-        for (i, is_empty) in data.iter().map(|x| *x != 0).enumerate() {
+        for (i, is_empty) in data[..len].iter().copied().enumerate() {
             let inner = if is_empty {
                 pin_box(stream::empty::<()>())
             } else {

tokio-stream/src/lib.rs

@@ -1,3 +1,4 @@
+#![allow(unknown_lints, unexpected_cfgs)]
 #![allow(
     clippy::cognitive_complexity,
     clippy::large_enum_variant,
@@ -54,7 +55,7 @@
 //!
 //! [async-stream]: https://docs.rs/async-stream
 //!
-//! # Conversion to and from AsyncRead/AsyncWrite
+//! # Conversion to and from `AsyncRead`/`AsyncWrite`
 //!
 //! It is often desirable to convert a `Stream` into an [`AsyncRead`],
 //! especially when dealing with plaintext formats streamed over the network.
@@ -63,12 +64,12 @@
 //! [`tokio-util`] provides the [`StreamReader`] and [`ReaderStream`]
 //! types when the io feature is enabled.
 //!
-//! [`tokio-util`]: https://docs.rs/tokio-util/0.4/tokio_util/codec/index.html
-//! [`tokio::io`]: https://docs.rs/tokio/1.0/tokio/io/index.html
-//! [`AsyncRead`]: https://docs.rs/tokio/1.0/tokio/io/trait.AsyncRead.html
-//! [`AsyncWrite`]: https://docs.rs/tokio/1.0/tokio/io/trait.AsyncWrite.html
-//! [`ReaderStream`]: https://docs.rs/tokio-util/0.4/tokio_util/io/struct.ReaderStream.html
-//! [`StreamReader`]: https://docs.rs/tokio-util/0.4/tokio_util/io/struct.StreamReader.html
+//! [`tokio-util`]: https://docs.rs/tokio-util/latest/tokio_util/codec/index.html
+//! [`tokio::io`]: https://docs.rs/tokio/latest/tokio/io/index.html
+//! [`AsyncRead`]: https://docs.rs/tokio/latest/tokio/io/trait.AsyncRead.html
+//! [`AsyncWrite`]: https://docs.rs/tokio/latest/tokio/io/trait.AsyncWrite.html
+//! [`ReaderStream`]: https://docs.rs/tokio-util/latest/tokio_util/io/struct.ReaderStream.html
+//! [`StreamReader`]: https://docs.rs/tokio-util/latest/tokio_util/io/struct.StreamReader.html
 
 #[macro_use]
 mod macros;
@@ -77,8 +78,22 @@ pub mod wrappers;
 
 mod stream_ext;
 pub use stream_ext::{collect::FromStream, StreamExt};
+/// Adapters for [`Stream`]s created by methods in [`StreamExt`].
+pub mod adapters {
+    pub use crate::stream_ext::{
+        Chain, Filter, FilterMap, Fuse, Map, MapWhile, Merge, Peekable, Skip, SkipWhile, Take,
+        TakeWhile, Then,
+    };
+    cfg_time! {
+        pub use crate::stream_ext::{ChunksTimeout, Timeout, TimeoutRepeating};
+    }
+}
+
 cfg_time! {
-    pub use stream_ext::timeout::{Elapsed, Timeout};
+    #[deprecated = "Import those symbols from adapters instead"]
+    #[doc(hidden)]
+    pub use stream_ext::timeout::Timeout;
+    pub use stream_ext::timeout::Elapsed;
 }
 
 mod empty;
@@ -96,5 +111,8 @@ pub use pending::{pending, Pending};
 mod stream_map;
 pub use stream_map::StreamMap;
 
+mod stream_close;
+pub use stream_close::StreamNotifyClose;
+
 #[doc(no_inline)]
 pub use futures_core::Stream;

tokio-stream/src/macros.rs

@@ -57,12 +57,3 @@ macro_rules! cfg_signal {
         )*
     }
 }
-
-macro_rules! ready {
-    ($e:expr $(,)?) => {
-        match $e {
-            std::task::Poll::Ready(t) => t,
-            std::task::Poll::Pending => return std::task::Poll::Pending,
-        }
-    };
-}

tokio-stream/src/once.rs

@@ -35,7 +35,7 @@ impl<I> Unpin for Once<I> {}
 /// ```
 pub fn once<T>(value: T) -> Once<T> {
     Once {
-        iter: crate::iter(Some(value).into_iter()),
+        iter: crate::iter(Some(value)),
     }
 }
 

tokio-stream/src/stream_close.rs

@@ -0,0 +1,93 @@
+use crate::Stream;
+use pin_project_lite::pin_project;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+
+pin_project! {
+    /// A `Stream` that wraps the values in an `Option`.
+    ///
+    /// Whenever the wrapped stream yields an item, this stream yields that item
+    /// wrapped in `Some`. When the inner stream ends, then this stream first
+    /// yields a `None` item, and then this stream will also end.
+    ///
+    /// # Example
+    ///
+    /// Using `StreamNotifyClose` to handle closed streams with `StreamMap`.
+    ///
+    /// ```
+    /// 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"),
+    ///         }
+    ///     }
+    /// }
+    /// ```
+    #[must_use = "streams do nothing unless polled"]
+    pub struct StreamNotifyClose<S> {
+        #[pin]
+        inner: Option<S>,
+    }
+}
+
+impl<S> StreamNotifyClose<S> {
+    /// Create a new `StreamNotifyClose`.
+    pub fn new(stream: S) -> Self {
+        Self {
+            inner: Some(stream),
+        }
+    }
+
+    /// Get back the inner `Stream`.
+    ///
+    /// Returns `None` if the stream has reached its end.
+    pub fn into_inner(self) -> Option<S> {
+        self.inner
+    }
+}
+
+impl<S> Stream for StreamNotifyClose<S>
+where
+    S: Stream,
+{
+    type Item = Option<S::Item>;
+
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        // We can't invoke poll_next after it ended, so we unset the inner stream as a marker.
+        match self
+            .as_mut()
+            .project()
+            .inner
+            .as_pin_mut()
+            .map(|stream| S::poll_next(stream, cx))
+        {
+            Some(Poll::Ready(Some(item))) => Poll::Ready(Some(Some(item))),
+            Some(Poll::Ready(None)) => {
+                self.project().inner.set(None);
+                Poll::Ready(Some(None))
+            }
+            Some(Poll::Pending) => Poll::Pending,
+            None => Poll::Ready(None),
+        }
+    }
+
+    #[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.
+            let (l, u) = inner.size_hint();
+            (l.saturating_add(1), u.and_then(|u| u.checked_add(1)))
+        } else {
+            (0, Some(0))
+        }
+    }
+}

tokio-stream/src/stream_ext.rs

@@ -8,61 +8,66 @@ mod any;
 use any::AnyFuture;
 
 mod chain;
-use chain::Chain;
+pub use chain::Chain;
 
 pub(crate) mod collect;
 use collect::{Collect, FromStream};
 
 mod filter;
-use filter::Filter;
+pub use filter::Filter;
 
 mod filter_map;
-use filter_map::FilterMap;
+pub use filter_map::FilterMap;
 
 mod fold;
 use fold::FoldFuture;
 
 mod fuse;
-use fuse::Fuse;
+pub use fuse::Fuse;
 
 mod map;
-use map::Map;
+pub use map::Map;
 
 mod map_while;
-use map_while::MapWhile;
+pub use map_while::MapWhile;
 
 mod merge;
-use merge::Merge;
+pub use merge::Merge;
 
 mod next;
 use next::Next;
 
 mod skip;
-use skip::Skip;
+pub use skip::Skip;
 
 mod skip_while;
-use skip_while::SkipWhile;
+pub use skip_while::SkipWhile;
 
 mod take;
-use take::Take;
+pub use take::Take;
 
 mod take_while;
-use take_while::TakeWhile;
+pub use take_while::TakeWhile;
 
 mod then;
-use then::Then;
+pub use then::Then;
 
 mod try_next;
 use try_next::TryNext;
 
+mod peekable;
+pub use peekable::Peekable;
+
 cfg_time! {
     pub(crate) mod timeout;
-    use timeout::Timeout;
-    use tokio::time::Duration;
+    pub(crate) mod timeout_repeating;
+    pub use timeout::Timeout;
+    pub use timeout_repeating::TimeoutRepeating;
+    use tokio::time::{Duration, Interval};
     mod throttle;
     use throttle::{throttle, Throttle};
     mod chunks_timeout;
-    use chunks_timeout::ChunksTimeout;
+    pub use chunks_timeout::ChunksTimeout;
 }
 
 /// An extension trait for the [`Stream`] trait that provides a variety of
@@ -846,8 +851,7 @@ pub trait StreamExt: Stream {
     ///
     /// `collect` streams all values, awaiting as needed. Values are pushed into
     /// a collection. A number of different target collection types are
-    /// supported, including [`Vec`](std::vec::Vec),
-    /// [`String`](std::string::String), and [`Bytes`].
+    /// supported, including [`Vec`], [`String`], and [`Bytes`].
     ///
     /// [`Bytes`]: https://docs.rs/bytes/0.6.0/bytes/struct.Bytes.html
     ///
@@ -924,7 +928,9 @@ pub trait StreamExt: Stream {
     /// If the wrapped stream yields a value before the deadline is reached, the
     /// value is returned. Otherwise, an error is returned. The caller may decide
     /// to continue consuming the stream and will eventually get the next source
-    /// stream value once it becomes available.
+    /// stream value once it becomes available. See
+    /// [`timeout_repeating`](StreamExt::timeout_repeating) for an alternative
+    /// where the timeouts will repeat.
     ///
     /// # Notes
     ///
@@ -971,7 +977,26 @@ pub trait StreamExt: Stream {
     /// assert_eq!(int_stream.try_next().await, Ok(None));
     /// # }
     /// ```
-    #[cfg(all(feature = "time"))]
+    ///
+    /// Once a timeout error is received, no further events will be received
+    /// unless the wrapped stream yields a value (timeouts do not repeat).
+    ///
+    /// ```
+    /// # #[tokio::main(flavor = "current_thread", start_paused = true)]
+    /// # async fn main() {
+    /// use tokio_stream::{StreamExt, wrappers::IntervalStream};
+    /// use std::time::Duration;
+    /// let interval_stream = IntervalStream::new(tokio::time::interval(Duration::from_millis(100)));
+    /// let timeout_stream = interval_stream.timeout(Duration::from_millis(10));
+    /// tokio::pin!(timeout_stream);
+    ///
+    /// // Only one timeout will be received between values in the source stream.
+    /// assert!(timeout_stream.try_next().await.is_ok());
+    /// assert!(timeout_stream.try_next().await.is_err(), "expected one timeout");
+    /// assert!(timeout_stream.try_next().await.is_ok(), "expected no more timeouts");
+    /// # }
+    /// ```
+    #[cfg(feature = "time")]
     #[cfg_attr(docsrs, doc(cfg(feature = "time")))]
     fn timeout(self, duration: Duration) -> Timeout<Self>
     where
@@ -980,6 +1005,94 @@ pub trait StreamExt: Stream {
         Timeout::new(self, duration)
     }
 
+    /// Applies a per-item timeout to the passed stream.
+    ///
+    /// `timeout_repeating()` takes an [`Interval`] that controls the time each
+    /// element of the stream has to complete before timing out.
+    ///
+    /// If the wrapped stream yields a value before the deadline is reached, the
+    /// value is returned. Otherwise, an error is returned. The caller may decide
+    /// to continue consuming the stream and will eventually get the next source
+    /// stream value once it becomes available. Unlike `timeout()`, if no value
+    /// becomes available before the deadline is reached, additional errors are
+    /// returned at the specified interval. See [`timeout`](StreamExt::timeout)
+    /// for an alternative where the timeouts do not repeat.
+    ///
+    /// # Notes
+    ///
+    /// This function consumes the stream passed into it and returns a
+    /// wrapped version of it.
+    ///
+    /// Polling the returned stream will continue to poll the inner stream even
+    /// if one or more items time out.
+    ///
+    /// # Examples
+    ///
+    /// Suppose we have a stream `int_stream` that yields 3 numbers (1, 2, 3):
+    ///
+    /// ```
+    /// # #[tokio::main]
+    /// # async fn main() {
+    /// use tokio_stream::{self as stream, StreamExt};
+    /// use std::time::Duration;
+    /// # let int_stream = stream::iter(1..=3);
+    ///
+    /// let int_stream = int_stream.timeout_repeating(tokio::time::interval(Duration::from_secs(1)));
+    /// tokio::pin!(int_stream);
+    ///
+    /// // When no items time out, we get the 3 elements in succession:
+    /// assert_eq!(int_stream.try_next().await, Ok(Some(1)));
+    /// assert_eq!(int_stream.try_next().await, Ok(Some(2)));
+    /// assert_eq!(int_stream.try_next().await, Ok(Some(3)));
+    /// assert_eq!(int_stream.try_next().await, Ok(None));
+    ///
+    /// // If the second item times out, we get an error and continue polling the stream:
+    /// # let mut int_stream = stream::iter(vec![Ok(1), Err(()), Ok(2), Ok(3)]);
+    /// assert_eq!(int_stream.try_next().await, Ok(Some(1)));
+    /// assert!(int_stream.try_next().await.is_err());
+    /// assert_eq!(int_stream.try_next().await, Ok(Some(2)));
+    /// assert_eq!(int_stream.try_next().await, Ok(Some(3)));
+    /// assert_eq!(int_stream.try_next().await, Ok(None));
+    ///
+    /// // If we want to stop consuming the source stream the first time an
+    /// // element times out, we can use the `take_while` operator:
+    /// # let int_stream = stream::iter(vec![Ok(1), Err(()), Ok(2), Ok(3)]);
+    /// let mut int_stream = int_stream.take_while(Result::is_ok);
+    ///
+    /// assert_eq!(int_stream.try_next().await, Ok(Some(1)));
+    /// assert_eq!(int_stream.try_next().await, Ok(None));
+    /// # }
+    /// ```
+    ///
+    /// Timeout errors will be continuously produced at the specified interval
+    /// until the wrapped stream yields a value.
+    ///
+    /// ```
+    /// # #[tokio::main(flavor = "current_thread", start_paused = true)]
+    /// # async fn main() {
+    /// use tokio_stream::{StreamExt, wrappers::IntervalStream};
+    /// use std::time::Duration;
+    /// let interval_stream = IntervalStream::new(tokio::time::interval(Duration::from_millis(23)));
+    /// let timeout_stream = interval_stream.timeout_repeating(tokio::time::interval(Duration::from_millis(9)));
+    /// tokio::pin!(timeout_stream);
+    ///
+    /// // Multiple timeouts will be received between values in the source stream.
+    /// assert!(timeout_stream.try_next().await.is_ok());
+    /// assert!(timeout_stream.try_next().await.is_err(), "expected one timeout");
+    /// assert!(timeout_stream.try_next().await.is_err(), "expected a second timeout");
+    /// // Will eventually receive another value from the source stream...
+    /// assert!(timeout_stream.try_next().await.is_ok(), "expected non-timeout");
+    /// # }
+    /// ```
+    #[cfg(feature = "time")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "time")))]
+    fn timeout_repeating(self, interval: Interval) -> TimeoutRepeating<Self>
+    where
+        Self: Sized,
+    {
+        TimeoutRepeating::new(self, interval)
+    }
+
     /// Slows down a stream by enforcing a delay between items.
     ///
     /// The underlying timer behind this utility has a granularity of one millisecond.
@@ -1001,7 +1114,7 @@ pub trait StreamExt: Stream {
     /// }
     /// # }
     /// ```
-    #[cfg(all(feature = "time"))]
+    #[cfg(feature = "time")]
     #[cfg_attr(docsrs, doc(cfg(feature = "time")))]
     fn throttle(self, duration: Duration) -> Throttle<Self>
     where
@@ -1066,6 +1179,31 @@ pub trait StreamExt: Stream {
         assert!(max_size > 0, "`max_size` must be non-zero.");
         ChunksTimeout::new(self, max_size, duration)
     }
+
+    /// Turns the stream into a peekable stream, whose next element can be peeked at without being
+    /// consumed.
+    /// ```rust
+    /// use tokio_stream::{self as stream, StreamExt};
+    ///
+    /// #[tokio::main]
+    /// # async fn _unused() {}
+    /// # #[tokio::main(flavor = "current_thread", start_paused = true)]
+    /// async fn main() {
+    ///     let iter = vec![1, 2, 3, 4].into_iter();
+    ///     let mut stream = stream::iter(iter).peekable();
+    ///
+    ///     assert_eq!(*stream.peek().await.unwrap(), 1);
+    ///     assert_eq!(*stream.peek().await.unwrap(), 1);
+    ///     assert_eq!(stream.next().await.unwrap(), 1);
+    ///     assert_eq!(*stream.peek().await.unwrap(), 2);
+    /// }
+    /// ```
+    fn peekable(self) -> Peekable<Self>
+    where
+        Self: Sized,
+    {
+        Peekable::new(self)
+    }
 }
 
 impl<St: ?Sized> StreamExt for St where St: Stream {}

tokio-stream/src/stream_ext/all.rs

@@ -3,7 +3,7 @@ use crate::Stream;
 use core::future::Future;
 use core::marker::PhantomPinned;
 use core::pin::Pin;
-use core::task::{Context, Poll};
+use core::task::{ready, Context, Poll};
 use pin_project_lite::pin_project;
 
 pin_project! {
@@ -42,7 +42,7 @@ where
 
         // Take a maximum of 32 items from the stream before yielding.
         for _ in 0..32 {
-            match futures_core::ready!(stream.as_mut().poll_next(cx)) {
+            match ready!(stream.as_mut().poll_next(cx)) {
                 Some(v) => {
                     if !(me.f)(v) {
                         return Poll::Ready(false);

tokio-stream/src/stream_ext/any.rs

@@ -3,7 +3,7 @@ use crate::Stream;
 use core::future::Future;
 use core::marker::PhantomPinned;
 use core::pin::Pin;
-use core::task::{Context, Poll};
+use core::task::{ready, Context, Poll};
 use pin_project_lite::pin_project;
 
 pin_project! {
@@ -42,7 +42,7 @@ where
 
         // Take a maximum of 32 items from the stream before yielding.
         for _ in 0..32 {
-            match futures_core::ready!(stream.as_mut().poll_next(cx)) {
+            match ready!(stream.as_mut().poll_next(cx)) {
                 Some(v) => {
                     if (me.f)(v) {
                         return Poll::Ready(true);

tokio-stream/src/stream_ext/chain.rs

@@ -2,7 +2,7 @@ use crate::stream_ext::Fuse;
 use crate::Stream;
 
 use core::pin::Pin;
-use core::task::{Context, Poll};
+use core::task::{ready, Context, Poll};
 use pin_project_lite::pin_project;
 
 pin_project! {

tokio-stream/src/stream_ext/chunks_timeout.rs

@@ -4,7 +4,7 @@ use tokio::time::{sleep, Sleep};
 
 use core::future::Future;
 use core::pin::Pin;
-use core::task::{Context, Poll};
+use core::task::{ready, Context, Poll};
 use pin_project_lite::pin_project;
 use std::time::Duration;
 

tokio-stream/src/stream_ext/collect.rs

@@ -4,7 +4,7 @@ use core::future::Future;
 use core::marker::PhantomPinned;
 use core::mem;
 use core::pin::Pin;
-use core::task::{Context, Poll};
+use core::task::{ready, Context, Poll};
 use pin_project_lite::pin_project;
 
 // Do not export this struct until `FromStream` can be unsealed.
@@ -26,7 +26,7 @@ pin_project! {
     }
 }
 
-/// Convert from a [`Stream`](crate::Stream).
+/// Convert from a [`Stream`].
 ///
 /// This trait is not intended to be used directly. Instead, call
 /// [`StreamExt::collect()`](super::StreamExt::collect).

tokio-stream/src/stream_ext/filter.rs

@@ -2,7 +2,7 @@ use crate::Stream;
 
 use core::fmt;
 use core::pin::Pin;
-use core::task::{Context, Poll};
+use core::task::{ready, Context, Poll};
 use pin_project_lite::pin_project;
 
 pin_project! {

tokio-stream/src/stream_ext/filter_map.rs

@@ -2,7 +2,7 @@ use crate::Stream;
 
 use core::fmt;
 use core::pin::Pin;
-use core::task::{Context, Poll};
+use core::task::{ready, Context, Poll};
 use pin_project_lite::pin_project;
 
 pin_project! {

tokio-stream/src/stream_ext/fold.rs

@@ -3,7 +3,7 @@ use crate::Stream;
 use core::future::Future;
 use core::marker::PhantomPinned;
 use core::pin::Pin;
-use core::task::{Context, Poll};
+use core::task::{ready, Context, Poll};
 use pin_project_lite::pin_project;
 
 pin_project! {

tokio-stream/src/stream_ext/fuse.rs

@@ -2,7 +2,7 @@ use crate::Stream;
 
 use pin_project_lite::pin_project;
 use std::pin::Pin;
-use std::task::{Context, Poll};
+use std::task::{ready, Context, Poll};
 
 pin_project! {
     /// Stream returned by [`fuse()`][super::StreamExt::fuse].

tokio-stream/src/stream_ext/merge.rs

@@ -66,25 +66,23 @@ where
     T: Stream,
     U: Stream<Item = T::Item>,
 {
-    use Poll::*;
-
     let mut done = true;
 
     match first.poll_next(cx) {
-        Ready(Some(val)) => return Ready(Some(val)),
-        Ready(None) => {}
-        Pending => done = false,
+        Poll::Ready(Some(val)) => return Poll::Ready(Some(val)),
+        Poll::Ready(None) => {}
+        Poll::Pending => done = false,
     }
 
     match second.poll_next(cx) {
-        Ready(Some(val)) => return Ready(Some(val)),
-        Ready(None) => {}
-        Pending => done = false,
+        Poll::Ready(Some(val)) => return Poll::Ready(Some(val)),
+        Poll::Ready(None) => {}
+        Poll::Pending => done = false,
     }
 
     if done {
-        Ready(None)
+        Poll::Ready(None)
     } else {
-        Pending
+        Poll::Pending
     }
 }

tokio-stream/src/stream_ext/peekable.rs

@@ -0,0 +1,50 @@
+use std::pin::Pin;
+use std::task::{Context, Poll};
+
+use futures_core::Stream;
+use pin_project_lite::pin_project;
+
+use crate::stream_ext::Fuse;
+use crate::StreamExt;
+
+pin_project! {
+    /// Stream returned by the [`peekable`](super::StreamExt::peekable) method.
+    pub struct Peekable<T: Stream> {
+        peek: Option<T::Item>,
+        #[pin]
+        stream: Fuse<T>,
+    }
+}
+
+impl<T: Stream> Peekable<T> {
+    pub(crate) fn new(stream: T) -> Self {
+        let stream = stream.fuse();
+        Self { peek: None, stream }
+    }
+
+    /// Peek at the next item in the stream.
+    pub async fn peek(&mut self) -> Option<&T::Item>
+    where
+        T: Unpin,
+    {
+        if let Some(ref it) = self.peek {
+            Some(it)
+        } else {
+            self.peek = self.next().await;
+            self.peek.as_ref()
+        }
+    }
+}
+
+impl<T: Stream> Stream for Peekable<T> {
+    type Item = T::Item;
+
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        let this = self.project();
+        if let Some(it) = this.peek.take() {
+            Poll::Ready(Some(it))
+        } else {
+            this.stream.poll_next(cx)
+        }
+    }
+}

tokio-stream/src/stream_ext/skip.rs

@@ -2,7 +2,7 @@ use crate::Stream;
 
 use core::fmt;
 use core::pin::Pin;
-use core::task::{Context, Poll};
+use core::task::{ready, Context, Poll};
 use pin_project_lite::pin_project;
 
 pin_project! {

tokio-stream/src/stream_ext/skip_while.rs

@@ -2,7 +2,7 @@ use crate::Stream;
 
 use core::fmt;
 use core::pin::Pin;
-use core::task::{Context, Poll};
+use core::task::{ready, Context, Poll};
 use pin_project_lite::pin_project;
 
 pin_project! {

tokio-stream/src/stream_ext/take.rs

@@ -64,11 +64,11 @@ where
 
         let (lower, upper) = self.stream.size_hint();
 
-        let lower = cmp::min(lower, self.remaining as usize);
+        let lower = cmp::min(lower, self.remaining);
 
         let upper = match upper {
-            Some(x) if x < self.remaining as usize => Some(x),
-            _ => Some(self.remaining as usize),
+            Some(x) if x < self.remaining => Some(x),
+            _ => Some(self.remaining),
         };
 
         (lower, upper)