From 6c6a23851cddf113b77de470dd6dab4538d2adb7 Mon Sep 17 00:00:00 2001
From: "Kamat, Trivikram" <16024985+trivikr@users.noreply.github.com>
Date: Wed, 13 May 2026 16:23:14 -0700
Subject: [PATCH 1/2] stream: uncork fromWritable writev on chunk error

Ensure fromWritable().writev() uncorks the wrapped Writable when
converting a later chunk throws. This prevents an internal cork from
leaking after ERR_INVALID_ARG_TYPE.

Fixes: https://github.com/nodejs/node/issues/63294

Signed-off-by: Kamat, Trivikram <16024985+trivikr@users.noreply.github.com>
Assisted-by: openai:gpt-5.5
---
 lib/internal/streams/iter/classic.js          | 24 ++++++++++++++-----
 .../test-stream-iter-writable-interop.js      | 16 +++++++++++++
 2 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/lib/internal/streams/iter/classic.js b/lib/internal/streams/iter/classic.js
index 18d1733d6ad648..a60b7cd417c5db 100644
--- a/lib/internal/streams/iter/classic.js
+++ b/lib/internal/streams/iter/classic.js
@@ -608,14 +608,26 @@ function fromWritable(writable, options = kNullPrototype) {
         return PromiseResolve();
       }
 
-      if (typeof writable.cork === 'function') writable.cork();
       let ok = true;
-      for (let i = 0; i < chunks.length; i++) {
-        const bytes = toUint8Array(chunks[i]);
-        totalBytes += TypedArrayPrototypeGetByteLength(bytes);
-        ok = writable.write(bytes);
+      if (typeof writable.cork === 'function' &&
+          typeof writable.uncork === 'function') {
+        writable.cork();
+        try {
+          for (let i = 0; i < chunks.length; i++) {
+            const bytes = toUint8Array(chunks[i]);
+            totalBytes += TypedArrayPrototypeGetByteLength(bytes);
+            ok = writable.write(bytes);
+          }
+        } finally {
+          writable.uncork();
+        }
+      } else {
+        for (let i = 0; i < chunks.length; i++) {
+          const bytes = toUint8Array(chunks[i]);
+          totalBytes += TypedArrayPrototypeGetByteLength(bytes);
+          ok = writable.write(bytes);
+        }
       }
-      if (typeof writable.uncork === 'function') writable.uncork();
 
       if (ok) return PromiseResolve();
 
diff --git a/test/parallel/test-stream-iter-writable-interop.js b/test/parallel/test-stream-iter-writable-interop.js
index 8a2ead0d0ee579..e7b83ac22841ce 100644
--- a/test/parallel/test-stream-iter-writable-interop.js
+++ b/test/parallel/test-stream-iter-writable-interop.js
@@ -550,6 +550,21 @@ function testWritevInvalidChunksType() {
   );
 }
 
+// =============================================================================
+// writev() uncorks when chunk validation throws
+// =============================================================================
+
+function testWritevInvalidChunkUncorks() {
+  const writable = new Writable({ write(chunk, enc, cb) { cb(); } });
+  const writer = fromWritable(writable);
+
+  assert.throws(
+    () => writer.writev([new Uint8Array([1]), 42]),
+    { code: 'ERR_INVALID_ARG_TYPE' },
+  );
+  assert.strictEqual(writable.writableCorked, 0);
+}
+
 // =============================================================================
 // Cached writer: second call returns same instance
 // =============================================================================
@@ -638,6 +653,7 @@ testDrainableNull();
 testDropOldestThrows();
 testInvalidBackpressureThrows();
 testWritevInvalidChunksType();
+testWritevInvalidChunkUncorks();
 testCachedWriter();
 testObjectModeThrows();
 

From 33ae1248bd523c74a116039992f0d95b8460257b Mon Sep 17 00:00:00 2001
From: "Kamat, Trivikram" <16024985+trivikr@users.noreply.github.com>
Date: Wed, 13 May 2026 16:36:02 -0700
Subject: [PATCH 2/2] stream: deduplicate classic writable writev loop

---
 lib/internal/streams/iter/classic.js | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/lib/internal/streams/iter/classic.js b/lib/internal/streams/iter/classic.js
index a60b7cd417c5db..6f978102d2b645 100644
--- a/lib/internal/streams/iter/classic.js
+++ b/lib/internal/streams/iter/classic.js
@@ -513,6 +513,16 @@ function fromWritable(writable, options = kNullPrototype) {
     return (writable.writableLength ?? 0) >= hwm;
   }
 
+  function writeChunks(chunks) {
+    let ok = true;
+    for (let i = 0; i < chunks.length; i++) {
+      const bytes = toUint8Array(chunks[i]);
+      totalBytes += TypedArrayPrototypeGetByteLength(bytes);
+      ok = writable.write(bytes);
+    }
+    return ok;
+  }
+
   const writer = {
     __proto__: null,
 
@@ -613,20 +623,12 @@ function fromWritable(writable, options = kNullPrototype) {
           typeof writable.uncork === 'function') {
         writable.cork();
         try {
-          for (let i = 0; i < chunks.length; i++) {
-            const bytes = toUint8Array(chunks[i]);
-            totalBytes += TypedArrayPrototypeGetByteLength(bytes);
-            ok = writable.write(bytes);
-          }
+          ok = writeChunks(chunks);
         } finally {
           writable.uncork();
         }
       } else {
-        for (let i = 0; i < chunks.length; i++) {
-          const bytes = toUint8Array(chunks[i]);
-          totalBytes += TypedArrayPrototypeGetByteLength(bytes);
-          ok = writable.write(bytes);
-        }
+        ok = writeChunks(chunks);
       }
 
       if (ok) return PromiseResolve();