stream: resolve stream/iter push() return() with its value

The iterator of a push() readable resolved return(value) with an
undefined value, unlike async generators and the other stream/iter
iterators. Since push() readables are no longer wrapped by from(), this
also applied to from() and pipeTo().

Resolve it with `value`.

Assisted-by: OpenCode
Signed-off-by: James M Snell <jasnell@gmail.com>

Author: jasnell

lib/internal/streams/iter/push.js

@@ -745,9 +745,9 @@ function createReadable(queue) {
         async next() {
           return queue.read();
         },
-        async return() {
+        async return(value) {
           queue.consumerReturn();
-          return new IterResult(true, undefined);
+          return new IterResult(true, value);
         },
         async throw(error) {
           queue.consumerThrow(error);

test/parallel/test-stream-iter-push-basic.js

@@ -3,7 +3,7 @@
 
 const common = require('../common');
 const assert = require('assert');
-const { push, text } = require('stream/iter');
+const { from, push, text } = require('stream/iter');
 
 async function testBasicWriteRead() {
   const { writer, readable } = push();
@@ -174,6 +174,21 @@ async function testInvalidBackpressure() {
   }
 }
 
+async function testReturnValue() {
+  // return(value) resolves with `value`, read directly or through from().
+  for (const getIterator of [
+    (readable) => readable[Symbol.asyncIterator](),
+    (readable) => from(readable)[Symbol.asyncIterator](),
+  ]) {
+    const { writer, readable } = push();
+    const iterator = getIterator(readable);
+    const result = await iterator.return('value');
+    assert.strictEqual(result.done, true);
+    assert.strictEqual(result.value, 'value');
+    assert.strictEqual(writer.canWrite, null);
+  }
+}
+
 Promise.all([
   testBasicWriteRead(),
   testMultipleWrites(),
@@ -187,4 +202,5 @@ Promise.all([
   testConsumerBreakWriteSyncReturnsFalse(),
   testPushWithTransforms(),
   testInvalidBackpressure(),
+  testReturnValue(),
 ]).then(common.mustCall());