fs: do not emit 'finish' before 'open' on write empty file

'finish' could previously be emitted before the file has been created when ending a write stream without having written any data. Refs: expressjs/multer#238 PR-URL: #29930 Reviewed-By: Rich Trott <rtrott@gmail.com> Reviewed-By: Matteo Collina <matteo.collina@gmail.com> Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
nodejs · targos · Oct 21, 2019 · Oct 4, 2019 · Oct 7, 2019 · Oct 8, 2019
commit 8ebc94562cb570a8f2331675dc83c37fd9fe7417
diff --git a/lib/internal/fs/streams.js b/lib/internal/fs/streams.js
@@ -272,6 +272,12 @@ Object.setPrototypeOf(WriteStream.prototype, Writable.prototype);
 Object.setPrototypeOf(WriteStream, Writable);
 
 WriteStream.prototype._final = function(callback) {
+  if (typeof this.fd !== 'number') {
+    return this.once('open', function() {
+      this._final(callback);
+    });
+  }
+
   if (this.autoClose) {
     this.destroy();
   }

diff --git a/test/parallel/test-fs-write-stream-end.js b/test/parallel/test-fs-write-stream-end.js
@@ -44,3 +44,17 @@ tmpdir.refresh();
     assert.strictEqual(content, 'a\n');
   }));
 }
+
+{
+  const file = path.join(tmpdir.path, 'write-end-test2.txt');
+  const stream = fs.createWriteStream(file);
+  stream.end();
+
+  let calledOpen = false;
+  stream.on('open', () => {
+    calledOpen = true;
+  });
+  stream.on('finish', common.mustCall(() => {
+    assert.strictEqual(calledOpen, true);
+  }));
+}