stream: fix 0 transform hwm backpressure

nodejs · aduh95 · Jul 24, 2022 · Jul 5, 2022 · Jul 5, 2022 · Jul 5, 2022
commit 446aba69a37e65932cce2878c3edd47619595d3c
diff --git a/lib/internal/streams/transform.js b/lib/internal/streams/transform.js
@@ -82,6 +82,15 @@ function Transform(options) {
   if (!(this instanceof Transform))
     return new Transform(options);
 
+  if (options && options.highWaterMark != null) {
+    options = {
+      ...options,
+      highWaterMark: null,
+      readableHighWaterMark: Math.max(1, options.highWaterMark),
+      writableHighWaterMark: 0
+    }
+  }
+
   Duplex.call(this, options);
 
   // We have implemented the _read method, and done the other things
@@ -164,9 +173,7 @@ Transform.prototype._write = function(chunk, encoding, callback) {
     if (
       wState.ended || // Backwards compat.
       length === rState.length || // Backwards compat.
-      rState.length < rState.highWaterMark ||
-      rState.highWaterMark === 0 ||
-      rState.length === 0
+      rState.length < rState.highWaterMark
     ) {
       callback();
     } else {

diff --git a/test/parallel/test-stream-passthrough-drain.js b/test/parallel/test-stream-passthrough-drain.js
@@ -1,8 +1,9 @@
 'use strict';
 const common = require('../common');
+const assert = require('assert')
 const { PassThrough } = require('stream');
 
 const pt = new PassThrough({ highWaterMark: 0 });
 pt.on('drain', common.mustCall());
-pt.write('hello');
+assert(!pt.write('hello1'));
 pt.read();