stream: observe abort while awaiting pipeTo source

Use the abort-aware iterator wrapper in the no-transform pipeTo()
path so a pending source read does not block AbortSignal handling.

Fixes: #64014

Signed-off-by: Kamat, Trivikram <16024985+trivikr@users.noreply.github.com>
Assisted-by: openai:gpt-5.5

Author: trivikr

lib/internal/streams/iter/pull.js

@@ -1090,7 +1090,7 @@ async function pipeTo(source, ...args) {
     } else if (transforms.length === 0) {
       // Fast path: no transforms - iterate normalized source directly
       if (signal) {
-        for await (const batch of normalized) {
+        for await (const batch of yieldAbortable(normalized, signal)) {
           signal.throwIfAborted();
           const p = writeBatch(batch);
           if (p) await p;

test/parallel/test-stream-iter-pipeto-signal.js

@@ -6,6 +6,7 @@
 
 const common = require('../common');
 const assert = require('assert');
+const { setTimeout } = require('timers/promises');
 const { pipeTo, from } = require('stream/iter');
 
 // pipeTo with live signal, no transforms — abort mid-stream
@@ -30,6 +31,31 @@ async function testPipeToLiveSignalNoTransforms() {
   assert.ok(written.length >= 1);
 }
 
+// pipeTo with live signal, no transforms — abort while waiting for next chunk
+async function testPipeToLiveSignalNoTransformsPendingNext() {
+  const ac = new AbortController();
+  const reason = new Error('abort reason');
+  const writer = {
+    write: common.mustNotCall(),
+  };
+
+  async function* source() {
+    await new Promise(() => {});
+  }
+
+  setTimeout(10).then(common.mustCall(() => ac.abort(reason)));
+
+  const result = await Promise.race([
+    assert.rejects(
+      () => pipeTo(source(), writer, { signal: ac.signal }),
+      reason,
+    ).then(() => 'aborted'),
+    setTimeout(1000, 'timed out'),
+  ]);
+
+  assert.strictEqual(result, 'aborted');
+}
+
 // pipeTo with live signal + transforms — abort mid-stream
 async function testPipeToLiveSignalWithTransforms() {
   const ac = new AbortController();
@@ -84,6 +110,7 @@ async function testPipeToLiveSignalWithTransformsCompletes() {
 
 Promise.all([
   testPipeToLiveSignalNoTransforms(),
+  testPipeToLiveSignalNoTransformsPendingNext(),
   testPipeToLiveSignalWithTransforms(),
   testPipeToLiveSignalCompletes(),
   testPipeToLiveSignalWithTransformsCompletes(),