domain: don't crash on "throw null"

Signed-off-by: Trevor Norris <trev.norris@gmail.com>

lib/domain.js

@@ -85,8 +85,10 @@ Domain.prototype._errorHandler = function errorHandler(er) {
   if (this._disposed)
     return true;
 
-  er.domain = this;
-  er.domainThrown = true;
+  if (!util.isPrimitive(er)) {
+    er.domain = this;
+    er.domainThrown = true;
+  }
   // wrap this in a try/catch so we don't get infinite throwing
   try {
     // One of three things will happen here.

test/simple/test-domain.js

@@ -261,3 +261,18 @@ assert.equal(result, 'return value');
 var fst = fs.createReadStream('stream for nonexistent file')
 d.add(fst)
 expectCaught++;
+
+[42, null, , false, function(){}, 'string'].forEach(function(something) {
+  var d = new domain.Domain();
+  d.run(function() {
+    process.nextTick(function() {
+      throw something;
+    });
+    expectCaught++;
+  });
+
+  d.on('error', function(er) {
+    assert.strictEqual(something, er);
+    caught++;
+  });
+});