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: https://github.com/expressjs/multer/issues/238

PR-URL: https://github.com/nodejs/node/pull/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>

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/internal/fs/streams.js b/lib/internal/fs/streams.js
index 3674a71f92..673dab34fb 100644
--- a/lib/internal/fs/streams.js
+++ b/lib/internal/fs/streams.js
@@ -284,6 +284,12 @@ 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();
   }