buffer: fix missing null/undefined check

The new implementation of Buffer missed the check for null/undefined as
the first argument to new Buffer(). Reintroduce the check and add test.

Fix: e8734c0 "buffer: implement Uint8Array backed Buffer"
Fix: https://github.com/nodejs/io.js/issues/2194
PR-URL: https://github.com/nodejs/io.js/pull/2195
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rod Vagg <rod@vagg.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/lib/buffer.js b/lib/buffer.js
index b9fe5bfb84..403c344bdb 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -105,6 +105,10 @@ function fromObject(obj) {
     return b;
   }
 
+  if (obj == null) {
+    throw new TypeError('must start with number, buffer, array or string');
+  }
+
   if (obj instanceof ArrayBuffer) {
     return binding.createFromArrayBuffer(obj);
   }