From 6d3920d579a3dc3a1e15875a15fb54e3ff4201c0 Mon Sep 17 00:00:00 2001
From: Khoo Hao Yit <40757009+KhooHaoYit@users.noreply.github.com>
Date: Thu, 17 Mar 2022 01:45:45 +0800
Subject: [PATCH] stream: do cleanup when iterator is destroyed

PR-URL: https://github.com/nodejs/node/pull/42320
Reviewed-By: Robert Nagy <ronagy@icloud.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Nitzan Uziely <linkgoron@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
---
 lib/internal/streams/readable.js                   |  5 ++++-
 .../test-stream-readable-async-iterators.js        | 14 ++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/lib/internal/streams/readable.js b/lib/internal/streams/readable.js
index 3fcd373cb1c708..4b7613fd13d081 100644
--- a/lib/internal/streams/readable.js
+++ b/lib/internal/streams/readable.js
@@ -1122,7 +1122,7 @@ async function* createAsyncIterator(stream, options) {
   stream.on('readable', next);
 
   let error;
-  eos(stream, { writable: false }, (err) => {
+  const cleanup = eos(stream, { writable: false }, (err) => {
     error = err ? aggregateTwoErrors(error, err) : null;
     callback();
     callback = nop;
@@ -1150,6 +1150,9 @@ async function* createAsyncIterator(stream, options) {
       (error === undefined || stream._readableState.autoDestroy)
     ) {
       destroyImpl.destroyer(stream, null);
+    } else {
+      stream.off('readable', next);
+      cleanup();
     }
   }
 }
diff --git a/test/parallel/test-stream-readable-async-iterators.js b/test/parallel/test-stream-readable-async-iterators.js
index 87184662139ae5..e8b69612014ca5 100644
--- a/test/parallel/test-stream-readable-async-iterators.js
+++ b/test/parallel/test-stream-readable-async-iterators.js
@@ -789,6 +789,20 @@ async function tests() {
       }
     );
   }
+
+  // Check for dangling listeners
+  (async function() {
+    const readable = createReadable();
+    const opts = { destroyOnReturn: false };
+    while (readable.readable) {
+      // eslint-disable-next-line no-unused-vars
+      for await (const chunk of readable.iterator(opts)) {
+        break;
+      }
+    }
+
+    assert.deepStrictEqual(readable.eventNames(), []);
+  })().then(common.mustCall());
 }
 
 {