From d4171e0eac185009ab05476a3a293956d3e278d8 Mon Sep 17 00:00:00 2001
From: Robert Nagy <ronagy@icloud.com>
Date: Sun, 6 Feb 2022 11:05:51 +0100
Subject: [PATCH] stream: resume stream on drain

Previously we would just resume "flowing" the stream without
reseting the "paused" state. Fixes this by properly using
pause/resume methods for .pipe.

Fixes: https://github.com/nodejs/node/issues/41785

PR-URL: https://github.com/nodejs/node/pull/41848
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
---
 lib/internal/streams/readable.js                 |  3 +--
 .../test-stream-readable-pause-and-resume.js     | 16 ++++++++++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/lib/internal/streams/readable.js b/lib/internal/streams/readable.js
index 30032360b3da60..fd04a068ce4969 100644
--- a/lib/internal/streams/readable.js
+++ b/lib/internal/streams/readable.js
@@ -807,8 +807,7 @@ function pipeOnDrain(src, dest) {
 
     if ((!state.awaitDrainWriters || state.awaitDrainWriters.size === 0) &&
       EE.listenerCount(src, 'data')) {
-      state.flowing = true;
-      flow(src);
+      src.resume();
     }
   };
 }
diff --git a/test/parallel/test-stream-readable-pause-and-resume.js b/test/parallel/test-stream-readable-pause-and-resume.js
index 294ef2c35d4608..53229ec3339e5c 100644
--- a/test/parallel/test-stream-readable-pause-and-resume.js
+++ b/test/parallel/test-stream-readable-pause-and-resume.js
@@ -56,3 +56,19 @@ function readAndPause() {
     assert(readable.isPaused());
   });
 }
+
+{
+  const { PassThrough } = require('stream');
+
+  const source3 = new PassThrough();
+  const target3 = new PassThrough();
+
+  const chunk = Buffer.allocUnsafe(1000);
+  while (target3.write(chunk));
+
+  source3.pipe(target3);
+  target3.on('drain', common.mustCall(() => {
+    assert(!source3.isPaused());
+  }));
+  target3.on('data', () => {});
+}