From 96510617ccf6e4fee58d18a9181a39e448e2def8 Mon Sep 17 00:00:00 2001
From: "Kamat, Trivikram" <16024985+trivikr@users.noreply.github.com>
Date: Sat, 23 May 2026 09:29:56 -0700
Subject: [PATCH] stream: settle pending stream iter reads on return

Resolve pending next() calls when stream/iter push and broadcast
consumers are returned, so the promises do not remain pending after
iterator cleanup.

Fixes: https://github.com/nodejs/node/issues/63519

Signed-off-by: Kamat, Trivikram <16024985+trivikr@users.noreply.github.com>
Assisted-by: openai:gpt-5.5
---
 lib/internal/streams/iter/broadcast.js            |  1 +
 lib/internal/streams/iter/push.js                 |  8 ++++++++
 test/parallel/test-stream-iter-broadcast-basic.js | 13 +++++++++++++
 test/parallel/test-stream-iter-push-basic.js      | 13 +++++++++++++
 4 files changed, 35 insertions(+)

diff --git a/lib/internal/streams/iter/broadcast.js b/lib/internal/streams/iter/broadcast.js
index e6a404729d6e0b..aa83c9636598ea 100644
--- a/lib/internal/streams/iter/broadcast.js
+++ b/lib/internal/streams/iter/broadcast.js
@@ -165,6 +165,7 @@ class BroadcastImpl {
 
     function detach() {
       state.detached = true;
+      state.resolve?.({ __proto__: null, done: true, value: undefined });
       state.resolve = null;
       state.reject = null;
       if (self.#deleteConsumer(state)) {
diff --git a/lib/internal/streams/iter/push.js b/lib/internal/streams/iter/push.js
index 1c367ff02bae71..b6e450e5e4bc59 100644
--- a/lib/internal/streams/iter/push.js
+++ b/lib/internal/streams/iter/push.js
@@ -423,6 +423,7 @@ class PushQueue {
     if (this.#consumerState !== 'active') return;
     this.#consumerState = 'returned';
     this.#cleanup();
+    this.#resolvePendingReadsDone();
     this.#rejectPendingWrites(
       new ERR_INVALID_STATE.TypeError('Stream closed by consumer'));
     // If closing, reject the pending end promise
@@ -526,6 +527,13 @@ class PushQueue {
     }
   }
 
+  #resolvePendingReadsDone() {
+    while (this.#pendingReads.length > 0) {
+      this.#pendingReads.shift().resolve(
+        { __proto__: null, value: undefined, done: true });
+    }
+  }
+
   #rejectPendingWrites(error) {
     while (this.#pendingWrites.length > 0) {
       this.#pendingWrites.shift().reject(error);
diff --git a/test/parallel/test-stream-iter-broadcast-basic.js b/test/parallel/test-stream-iter-broadcast-basic.js
index ab2c81304ec2ac..32c1750fb4cbfd 100644
--- a/test/parallel/test-stream-iter-broadcast-basic.js
+++ b/test/parallel/test-stream-iter-broadcast-basic.js
@@ -161,6 +161,18 @@ async function testCancelWithReason() {
   assert.strictEqual(result.message, 'cancelled');
 }
 
+async function testPendingNextSettlesAfterReturn() {
+  const { broadcast: bc } = broadcast();
+  const iter = bc.push()[Symbol.asyncIterator]();
+
+  const pendingNext = iter.next();
+  await iter.return();
+
+  const result = await pendingNext;
+  assert.strictEqual(result.done, true);
+  assert.strictEqual(result.value, undefined);
+}
+
 // =============================================================================
 // Writer fail detaches consumers
 // =============================================================================
@@ -254,6 +266,7 @@ Promise.all([
   testCancelWithoutReason(),
   testCancelWithReason(),
   testCancelWithFalsyReason(),
+  testPendingNextSettlesAfterReturn(),
   testFailDetachesConsumers(),
   testWriterFailIdempotent(),
   testLateJoinerSeesBufferedData(),
diff --git a/test/parallel/test-stream-iter-push-basic.js b/test/parallel/test-stream-iter-push-basic.js
index 22d5b26c830a47..713f6cc9b7d29e 100644
--- a/test/parallel/test-stream-iter-push-basic.js
+++ b/test/parallel/test-stream-iter-push-basic.js
@@ -135,6 +135,18 @@ async function testConsumerBreakWriteSyncReturnsFalse() {
   assert.strictEqual(writer.desiredSize, null);
 }
 
+async function testPendingNextSettlesAfterReturn() {
+  const { readable } = push();
+  const iter = readable[Symbol.asyncIterator]();
+
+  const pendingNext = iter.next();
+  await iter.return();
+
+  const result = await pendingNext;
+  assert.strictEqual(result.done, true);
+  assert.strictEqual(result.value, undefined);
+}
+
 async function testPushWithTransforms() {
   const upper = (chunks) => {
     if (chunks === null) return null;
@@ -177,6 +189,7 @@ Promise.all([
   testAbortSignal(),
   testPreAbortedSignal(),
   testConsumerBreakWriteSyncReturnsFalse(),
+  testPendingNextSettlesAfterReturn(),
   testPushWithTransforms(),
   testInvalidBackpressure(),
 ]).then(common.mustCall());