From b8a169875f7015c35322e2b51c623ac7c78f0d1d Mon Sep 17 00:00:00 2001
From: Gil Pedersen <git@gpost.dk>
Date: Fri, 1 Jul 2022 21:42:26 +0200
Subject: [PATCH] stream: fix Transform with hwm 0 regression
Fixes: https://github.com/nodejs/node/issues/40935
Refs: https://github.com/nodejs/node/pull/40947
Refs: https://github.com/nodejs/node/issues/42457
---
lib/internal/streams/transform.js | 2 +-
test/parallel/test-stream-transform-hwm0.js | 28 +++++++++++++++++++++
2 files changed, 29 insertions(+), 1 deletion(-)
create mode 100644 test/parallel/test-stream-transform-hwm0.js
diff --git a/lib/internal/streams/transform.js b/lib/internal/streams/transform.js
index fdac76e4062b4b..3c5cac92467a21 100644
--- a/lib/internal/streams/transform.js
+++ b/lib/internal/streams/transform.js
@@ -165,12 +165,12 @@ 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();
} else {
this[kCallback] = callback;
+ rState.needReadable = true; // Always call _read() on the next read() call
}
});
};
diff --git a/test/parallel/test-stream-transform-hwm0.js b/test/parallel/test-stream-transform-hwm0.js
new file mode 100644
index 00000000000000..8e8971f21fa472
--- /dev/null
+++ b/test/parallel/test-stream-transform-hwm0.js
@@ -0,0 +1,28 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+const { Transform } = require('stream');
+
+const t = new Transform({
+ objectMode: true, highWaterMark: 0,
+ transform(chunk, enc, callback) {
+ process.nextTick(() => callback(null, chunk, enc));
+ }
+});
+
+assert.strictEqual(t.write(1), false);
+t.on('drain', common.mustCall(() => {
+ assert.strictEqual(t.write(2), false);
+ t.end();
+}));
+
+t.once('readable', common.mustCall(() => {
+ assert.strictEqual(t.read(), 1);
+ setImmediate(common.mustCall(() => {
+ assert.strictEqual(t.read(), null);
+ t.once('readable', common.mustCall(() => {
+ assert.strictEqual(t.read(), 2);
+ }));
+ }));
+}));