From d111d7b91c16ec420f231da4f6877a9b446de6d8 Mon Sep 17 00:00:00 2001
From: Anna Henningsen <anna@addaleax.net>
Date: Wed, 21 Mar 2018 13:01:41 +0100
Subject: [PATCH] stream: give error message if `write()` cb called twice

Otherwise, this condition would result in an error that just reads
`cb is not a function`, and which additionally could have lost
stack trace context through a `process.nextTick()` call.

PR-URL: https://github.com/nodejs/node/pull/19510
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
---
 lib/_stream_writable.js                       |  4 ++
 .../test-stream-writable-write-cb-twice.js    | 49 +++++++++++++++++++
 2 files changed, 53 insertions(+)
 create mode 100644 test/parallel/test-stream-writable-write-cb-twice.js

diff --git a/lib/_stream_writable.js b/lib/_stream_writable.js
index df1d4076d02..d21daf0541d 100644
--- a/lib/_stream_writable.js
+++ b/lib/_stream_writable.js
@@ -37,6 +37,7 @@ const { getHighWaterMark } = require('internal/streams/state');
 const {
   ERR_INVALID_ARG_TYPE,
   ERR_METHOD_NOT_IMPLEMENTED,
+  ERR_MULTIPLE_CALLBACK,
   ERR_STREAM_CANNOT_PIPE,
   ERR_STREAM_DESTROYED,
   ERR_STREAM_NULL_VALUES,
@@ -449,6 +450,9 @@ function onwrite(stream, er) {
   var sync = state.sync;
   var cb = state.writecb;
 
+  if (typeof cb !== 'function')
+    throw new ERR_MULTIPLE_CALLBACK();
+
   onwriteStateUpdate(state);
 
   if (er)
diff --git a/test/parallel/test-stream-writable-write-cb-twice.js b/test/parallel/test-stream-writable-write-cb-twice.js
new file mode 100644
index 00000000000..f066a0ecc4f
--- /dev/null
+++ b/test/parallel/test-stream-writable-write-cb-twice.js
@@ -0,0 +1,49 @@
+'use strict';
+const common = require('../common');
+const { Writable } = require('stream');
+
+{
+  // Sync + Sync
+  const writable = new Writable({
+    write: common.mustCall((buf, enc, cb) => {
+      cb();
+      common.expectsError(cb, {
+        code: 'ERR_MULTIPLE_CALLBACK',
+        type: Error
+      });
+    })
+  });
+  writable.write('hi');
+}
+
+{
+  // Sync + Async
+  const writable = new Writable({
+    write: common.mustCall((buf, enc, cb) => {
+      cb();
+      process.nextTick(() => {
+        common.expectsError(cb, {
+          code: 'ERR_MULTIPLE_CALLBACK',
+          type: Error
+        });
+      });
+    })
+  });
+  writable.write('hi');
+}
+
+{
+  // Async + Async
+  const writable = new Writable({
+    write: common.mustCall((buf, enc, cb) => {
+      process.nextTick(cb);
+      process.nextTick(() => {
+        common.expectsError(cb, {
+          code: 'ERR_MULTIPLE_CALLBACK',
+          type: Error
+        });
+      });
+    })
+  });
+  writable.write('hi');
+}