stream: adjust src hwm when pipelining

Author: ronag

lib/internal/streams/pipeline.js

@@ -294,7 +294,7 @@ function pipelineImpl(streams, callback, opts) {
       }
     } else if (isNodeStream(stream)) {
       if (isReadableNodeStream(ret)) {
-        ret.pipe(stream);
+        pipe(ret, stream);
 
         // Compat. Before node v10.12.0 stdio used to throw an error so
         // pipe() did/does not end() stdio destinations.
@@ -321,4 +321,45 @@ function pipelineImpl(streams, callback, opts) {
   return ret;
 }
 
+function pipe (src, dst) {
+  const state = src._readableState;
+
+  if (typeof src.read !== 'function' && state) {
+    src.pipe(dst);
+    return;
+  }
+
+  src
+    .on('end', end)
+    .on('readable', pump);
+  dst
+    .on('drain', pump);
+
+  function end () {
+    dst.end();
+  }
+
+  function pump () {
+    if (dst.writableNeedDrain) {
+      return;
+    }
+
+    while (true) {
+      state.highwaterMark = dst.writableHighwaterMark || dst.highwaterMark || null;
+
+      const chunk = src.read();
+
+      if (chunk === null) {
+        return;
+      }
+
+      if (!dst.write(chunk)) {
+        return;
+      }
+    }
+  }
+
+  process.nextTick(pump);
+}
+
 module.exports = { pipelineImpl, pipeline };

test/parallel/test-stream-pipeline.js

@@ -22,9 +22,7 @@ const tsp = require('timers/promises');
   let finished = false;
   const processed = [];
   const expected = [
-    Buffer.from('a'),
-    Buffer.from('b'),
-    Buffer.from('c'),
+    Buffer.from('abc')
   ];
 
   const read = new Readable({
@@ -348,8 +346,7 @@ const tsp = require('timers/promises');
   };
 
   const expected = [
-    Buffer.from('hello'),
-    Buffer.from('world'),
+    Buffer.from('helloworld')
   ];
 
   const rs = new Readable({
@@ -985,7 +982,7 @@ const tsp = require('timers/promises');
   // Make sure 'close' before 'end' finishes without error
   // if readable has received eof.
   // Ref: https://github.com/nodejs/node/issues/29699
-  const r = new Readable();
+  const r = new Readable(({ read() {} }));
   const w = new Writable({
     write(chunk, encoding, cb) {
       cb();
@@ -1350,7 +1347,7 @@ const tsp = require('timers/promises');
   });
   const cb = common.mustCall((err) => {
     assert.strictEqual(err.name, 'AbortError');
-    assert.strictEqual(res, '012345');
+    assert.strictEqual(res, '01234');
     assert.strictEqual(w.destroyed, true);
     assert.strictEqual(r.destroyed, true);
     assert.strictEqual(pipelined.destroyed, true);

test/parallel/test-stream-promises.js

@@ -25,9 +25,7 @@ assert.strictEqual(finished, promisify(stream.finished));
   let finished = false;
   const processed = [];
   const expected = [
-    Buffer.from('a'),
-    Buffer.from('b'),
-    Buffer.from('c'),
+    Buffer.from('abc'),
   ];
 
   const read = new Readable({