From 95b8895da88d757aef8bc24426286b171e2e2406 Mon Sep 17 00:00:00 2001
From: Nanasi <71248588+spellsaif@users.noreply.github.com>
Date: Wed, 24 Jun 2026 18:08:36 +0530
Subject: [PATCH] stream: update coop handling for empty and once (#8227)

---
 tokio-stream/src/empty.rs | 10 +++++++++-
 tokio-stream/src/once.rs  | 28 +++++++++++++++++++---------
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/tokio-stream/src/empty.rs b/tokio-stream/src/empty.rs
index 85d70079a..d90dff502 100644
--- a/tokio-stream/src/empty.rs
+++ b/tokio-stream/src/empty.rs
@@ -40,7 +40,15 @@ pub const fn empty<T>() -> Empty<T> {
 impl<T> Stream for Empty<T> {
     type Item = T;
 
-    fn poll_next(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Option<T>> {
+    fn poll_next(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Option<T>> {
+        #[cfg(feature = "rt")]
+        {
+            use tokio::task::coop;
+
+            let coop = std::task::ready!(coop::poll_proceed(_cx));
+            coop.made_progress();
+        }
+
         Poll::Ready(None)
     }
 
diff --git a/tokio-stream/src/once.rs b/tokio-stream/src/once.rs
index ccde62819..7740c4db3 100644
--- a/tokio-stream/src/once.rs
+++ b/tokio-stream/src/once.rs
@@ -1,6 +1,5 @@
-use crate::{Iter, Stream};
+use crate::Stream;
 
-use core::option;
 use core::pin::Pin;
 use core::task::{Context, Poll};
 
@@ -8,7 +7,7 @@ use core::task::{Context, Poll};
 #[derive(Debug)]
 #[must_use = "streams do nothing unless polled"]
 pub struct Once<T> {
-    iter: Iter<option::IntoIter<T>>,
+    value: Option<T>,
 }
 
 impl<I> Unpin for Once<I> {}
@@ -34,19 +33,30 @@ impl<I> Unpin for Once<I> {}
 /// # }
 /// ```
 pub fn once<T>(value: T) -> Once<T> {
-    Once {
-        iter: crate::iter(Some(value)),
-    }
+    Once { value: Some(value) }
 }
 
 impl<T> Stream for Once<T> {
     type Item = T;
 
-    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<T>> {
-        Pin::new(&mut self.iter).poll_next(cx)
+    fn poll_next(mut self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Option<T>> {
+        #[cfg(feature = "rt")]
+        {
+            use tokio::task::coop;
+
+            let coop = std::task::ready!(coop::poll_proceed(_cx));
+
+            coop.made_progress();
+        }
+
+        Poll::Ready(self.value.take())
     }
 
     fn size_hint(&self) -> (usize, Option<usize>) {
-        self.iter.size_hint()
+        if self.value.is_some() {
+            (1, Some(1))
+        } else {
+            (0, Some(0))
+        }
     }
 }