Return last error when PoolCluster exhausts connection retries

fixes #818

Author: dougwilson

Changes.md

@@ -11,6 +11,7 @@ you spot any mistakes.
 * Clone connection config for new pool connections
 * Default `connectTimeout` to 2 minutes
 * Reject unauthorized SSL connections (use `ssl.rejectUnauthorized` to override) #816
+* Return last error when PoolCluster exhausts connection retries #818
 * Throw on unknown SSL profile name #817
 * User newer TLS functions when available #809
 

lib/PoolCluster.js

@@ -136,7 +136,11 @@ PoolCluster.prototype._increaseErrorCount = function(node) {
 
       this.emit('remove', node.id);
     }
+
+    return true;
   }
+
+  return false;
 };
 
 PoolCluster.prototype._decreaseErrorCount = function(node) {
@@ -150,9 +154,9 @@ PoolCluster.prototype._getConnection = function(node, cb) {
 
   node.pool.getConnection(function (err, connection) {
     if (err) {
-      self._increaseErrorCount(node);
+      var removed = self._increaseErrorCount(node);
 
-      if (self._canRetry) {
+      if (!removed && self._canRetry) {
         return cb(null, 'retry');
       } else {
         return cb(err);

test/integration/pool/test-cluster.js

@@ -221,7 +221,7 @@ function createPoolCluster(clusterConfig, poolConfig) {
   cluster.of('*', 'RR').getConnection(function (err, connection) {
     cluster.end();
 
-    assert.ok(err === null);
+    assert.ifError(err);
     assert.equal(connection._clusterId, 'CORRECT');
 
     assert.equal(removedNodeId, 'ERROR');

test/unit/pool-cluster/test-connection-error.js

@@ -0,0 +1,29 @@
+var assert  = require('assert');
+var common  = require('../../common');
+var cluster = common.createPoolCluster({
+  canRetry             : true,
+  removeNodeErrorCount : 5
+});
+var server  = common.createFakeServer();
+
+var connCount  = 0;
+var poolConfig = common.getTestConfig({port: common.fakeServerPort});
+cluster.add('MASTER', poolConfig);
+
+server.listen(common.fakeServerPort, function(err) {
+  assert.ifError(err);
+
+  cluster.getConnection('MASTER', function(err, conn){
+    assert.ok(err);
+    assert.equal(err.code, 'ER_HOST_NOT_PRIVILEGED');
+    assert.equal(err.fatal, true);
+    assert.equal(connCount, 5);
+    server.destroy();
+  });
+});
+
+server.on('connection', function(incomingConnection) {
+  var errno = 1130; // ER_HOST_NOT_PRIVILEGED
+  connCount += 1;
+  incomingConnection.deny('You suck.', errno);
+});