allow reconnecting after failed connect.

If connecting fails, then set _conn = NULL so that other commands also fail with not connected error. Also, from mysql documentation: "If you call mysql_sqlstate()  after mysql_real_connect()  fails, mysql_sqlstate() might not return a useful value". We don't need to keep a connection object which has failed.

src/mysql_bindings_connection.cc

@@ -102,7 +102,9 @@ bool MysqlConn::Connect(const char* hostname,
     connect_error = mysql_error(_conn);
 
     if (unsuccessful) {
+        mysql_close(_conn);
         connected = false;
+        _conn = NULL;
         return false;
     }
 

tests/test-class-mysqlconn.js

@@ -296,15 +296,12 @@ exports.SetCharset = function (test) {
 };
 
 exports.SqlState = function (test) {
-  test.expect(4);
+  test.expect(2);
 
   var conn = mysql_libmysqlclient.createConnection(cfg.host, cfg.user, cfg.password, cfg.database), res;
   test.ok(conn, "mysql_libmysqlclient.createConnection(host, user, password, database)");
   test.equals(conn.sqlState(), "00000", "conn.sqlState() after connection to allowed database");
   conn.close();
-  res = conn.connect(cfg.host, cfg.user, cfg.password, cfg.database_denied);
-  test.ok(!res, "conn.connect(cfg.host, cfg.user, cfg.password, cfg.database_denied)");
-  test.equals(conn.sqlState(), "42000", "conn.sqlState() after connection to denied database");
 
   test.done();
 };

tests/test-connect-different-args.js

@@ -64,3 +64,13 @@ exports.Connect_DeniedDb = function (test) {
   test.done();
 };
 
+exports.Connect_DeniedFollowedByAllowedDb = function (test) {
+  test.expect(2);
+
+  var conn = mysql_libmysqlclient.createConnection();
+  test.ok(!conn.connect(cfg.host, cfg.user, cfg.password, cfg.database_denied), "conn.connect() for denied database");
+
+  test.ok(conn.connect(cfg.host, cfg.user, cfg.password, cfg.database), "conn.connect() for allowed database");
+  test.done();
+};
+