Fix a sync callback when sequence enqueue fails

fixes #1147

Author: dougwilson

Changes.md

@@ -6,6 +6,7 @@ you spot any mistakes.
 
 ## HEAD
 
+* Fix a sync callback when sequence enqueue fails #1147
 * Provide static require analysis
 
 ## v2.7.0 (2015-05-27)

lib/protocol/Protocol.js

@@ -183,7 +183,7 @@ Protocol.prototype._enqueue = function(sequence) {
   return sequence;
 };
 
-Protocol.prototype._validateEnqueue = function(sequence) {
+Protocol.prototype._validateEnqueue = function _validateEnqueue(sequence) {
   var err;
   var prefix = 'Cannot enqueue ' + sequence.constructor.name;
   var prefixBefore = prefix + ' before ';
@@ -211,11 +211,14 @@ Protocol.prototype._validateEnqueue = function(sequence) {
   var self  = this;
   err.fatal = false;
 
-  sequence
-    .on('error', function(err) {
-      self._delegateError(err, sequence);
-    })
-    .end(err);
+  // add error handler
+  sequence.on('error', function (err) {
+    self._delegateError(err, sequence);
+  });
+
+  process.nextTick(function () {
+    sequence.end(err);
+  });
 
   return false;
 };

test/unit/connection/test-query-after-destroy.js

@@ -7,12 +7,17 @@ var server = common.createFakeServer();
 server.listen(common.fakeServerPort, function (err) {
   assert.ifError(err);
 
+  var sync = true;
+
   connection.destroy();
 
   connection.query('SELECT 1', function (err) {
+    assert.ok(!sync);
     assert.ok(err);
     assert.equal(err.fatal, false);
     assert.equal(err.code, 'PROTOCOL_ENQUEUE_AFTER_DESTROY');
     server.destroy();
   });
+
+  sync = false;
 });