From 5c5608e11ff3ae9a9c598a6355b98933142a4d81 Mon Sep 17 00:00:00 2001
From: RafaelGSS <rafael.nunu@hotmail.com>
Date: Sat, 20 Nov 2021 23:44:38 -0300
Subject: [PATCH] streams: fix enqueue race condition on esm modules

---
 lib/internal/webstreams/readablestream.js   | 36 ++++++++++-----------
 test/parallel/test-whatwg-readablestream.js | 33 +++++++++++++++++++
 2 files changed, 50 insertions(+), 19 deletions(-)

diff --git a/lib/internal/webstreams/readablestream.js b/lib/internal/webstreams/readablestream.js
index fe9b26b991f04e..a88d166f886a94 100644
--- a/lib/internal/webstreams/readablestream.js
+++ b/lib/internal/webstreams/readablestream.js
@@ -1403,25 +1403,23 @@ function readableStreamTee(stream, cloneForBranch2) {
     reading = true;
     const readRequest = {
       [kChunk](value) {
-        queueMicrotask(() => {
-          reading = false;
-          const value1 = value;
-          let value2 = value;
-          if (!canceled2 && cloneForBranch2) {
-            // Structured Clone
-            value2 = deserialize(serialize(value2));
-          }
-          if (!canceled1) {
-            readableStreamDefaultControllerEnqueue(
-              branch1[kState].controller,
-              value1);
-          }
-          if (!canceled2) {
-            readableStreamDefaultControllerEnqueue(
-              branch2[kState].controller,
-              value2);
-          }
-        });
+        reading = false;
+        const value1 = value;
+        let value2 = value;
+        if (!canceled2 && cloneForBranch2) {
+          // Structured Clone
+          value2 = deserialize(serialize(value2));
+        }
+        if (!canceled1) {
+          readableStreamDefaultControllerEnqueue(
+            branch1[kState].controller,
+            value1);
+        }
+        if (!canceled2) {
+          readableStreamDefaultControllerEnqueue(
+            branch2[kState].controller,
+            value2);
+        }
       },
       [kClose]() {
         reading = false;
diff --git a/test/parallel/test-whatwg-readablestream.js b/test/parallel/test-whatwg-readablestream.js
index c8b82fa9823786..edfbdfee67841b 100644
--- a/test/parallel/test-whatwg-readablestream.js
+++ b/test/parallel/test-whatwg-readablestream.js
@@ -1488,6 +1488,39 @@ class Source {
     common.mustCall(({ value }) => assert.strictEqual(value, 'hello')));
 }
 
+{
+  // Test tee() with close in the nextTick after enqueue
+  async function read(stream) {
+    const chunks = [];
+    for await (const chunk of stream)
+      chunks.push(chunk);
+    return Buffer.concat(chunks).toString();
+  }
+
+  const [r1, r2] = new ReadableStream({
+    start(controller) {
+      process.nextTick(() => {
+        controller.enqueue(new Uint8Array([102, 111, 111, 98, 97, 114]))
+
+        process.nextTick(() => {
+          controller.close()
+        })
+      })
+    }
+  }).tee();
+
+  (async () => {
+    const [dataReader1, dataReader2] = await Promise.all([
+      read(r1),
+      read(r2),
+    ]);
+
+    assert.strictEqual(dataReader1, dataReader2);
+    assert.strictEqual(dataReader1, 'foobar');
+    assert.strictEqual(dataReader2, 'foobar');
+  })().then(common.mustCall());
+}
+
 {
   assert.throws(() => {
     readableByteStreamControllerConvertPullIntoDescriptor({