From 37f1dd9ccdee8c54e1a3465f73e727eb87555fe5 Mon Sep 17 00:00:00 2001
From: Robert Nagy <ronagy@icloud.com>
Date: Wed, 24 Nov 2021 09:42:24 +0100
Subject: [PATCH] stream: drain Transform with 0 highWaterMark
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Fixes: https://github.com/nodejs/node/issues/40935

PR-URL: https://github.com/nodejs/node/pull/40947
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
---
 lib/internal/streams/transform.js              | 1 +
 test/parallel/test-stream-passthrough-drain.js | 8 ++++++++
 2 files changed, 9 insertions(+)
 create mode 100644 test/parallel/test-stream-passthrough-drain.js

diff --git a/lib/internal/streams/transform.js b/lib/internal/streams/transform.js
index 26e0b07c2956c8..cbd23185fad291 100644
--- a/lib/internal/streams/transform.js
+++ b/lib/internal/streams/transform.js
@@ -196,6 +196,7 @@ Transform.prototype._write = function(chunk, encoding, callback) {
       wState.ended || // Backwards compat.
       length === rState.length || // Backwards compat.
       rState.length < rState.highWaterMark ||
+      rState.highWaterMark === 0 ||
       rState.length === 0
     ) {
       callback();
diff --git a/test/parallel/test-stream-passthrough-drain.js b/test/parallel/test-stream-passthrough-drain.js
new file mode 100644
index 00000000000000..f5c98947e21e2e
--- /dev/null
+++ b/test/parallel/test-stream-passthrough-drain.js
@@ -0,0 +1,8 @@
+'use strict';
+const common = require('../common');
+const { PassThrough } = require('stream');
+
+const pt = new PassThrough({ highWaterMark: 0 });
+pt.on('drain', common.mustCall());
+pt.write('hello');
+pt.read();