smalloc: check if obj has external data

PR-URL: https://github.com/joyent/node/pull/8655
Reviewed-by: Trevor Norris <trev.norris@gmail.com>

lib/smalloc.js

@@ -86,6 +86,8 @@ function dispose(obj) {
     throw new TypeError('obj must be an Object');
   if (util.isBuffer(obj))
     throw new TypeError('obj cannot be a Buffer');
+  if (!smalloc.hasExternalData(obj))
+    throw new Error('obj has no external array data');
 
   smalloc.dispose(obj);
 }

test/simple/test-smalloc.js

@@ -314,11 +314,15 @@ for (var i = 0; i < 5; i++)
 
 // only allow object to be passed to dispose
 assert.throws(function() {
-  alloc.dispose(null);
+  smalloc.dispose(null);
 });
 
 
 // can't dispose a Buffer
 assert.throws(function() {
-  alloc.dispose(new Buffer());
+  smalloc.dispose(new Buffer());
+});
+
+assert.throws(function() {
+  smalloc.dispose({});
 });