dependency upgrades for v2.18 release cycle (#2314)

vendor/github.com/go-sql-driver/mysql/driver.go

@@ -55,6 +55,15 @@ func RegisterDialContext(net string, dial DialContextFunc) {
 	dials[net] = dial
 }
 
+// DeregisterDialContext removes the custom dial function registered with the given net.
+func DeregisterDialContext(net string) {
+	dialsLock.Lock()
+	defer dialsLock.Unlock()
+	if dials != nil {
+		delete(dials, net)
+	}
+}
+
 // RegisterDial registers a custom dial function. It can then be used by the
 // network address mynet(addr), where mynet is the registered new network.
 // addr is passed as a parameter to the dial function.
@@ -74,14 +83,18 @@ func (d MySQLDriver) Open(dsn string) (driver.Conn, error) {
 	if err != nil {
 		return nil, err
 	}
-	c := &connector{
-		cfg: cfg,
-	}
+	c := newConnector(cfg)
 	return c.Connect(context.Background())
 }
 
+// This variable can be replaced with -ldflags like below:
+// go build "-ldflags=-X github.com/go-sql-driver/mysql.driverName=custom"
+var driverName = "mysql"
+
 func init() {
-	sql.Register("mysql", &MySQLDriver{})
+	if driverName != "" {
+		sql.Register(driverName, &MySQLDriver{})
+	}
 }
 
 // NewConnector returns new driver.Connector.
@@ -92,7 +105,7 @@ func NewConnector(cfg *Config) (driver.Connector, error) {
 	if err := cfg.normalize(); err != nil {
 		return nil, err
 	}
-	return &connector{cfg: cfg}, nil
+	return newConnector(cfg), nil
 }
 
 // OpenConnector implements driver.DriverContext.
@@ -101,7 +114,5 @@ func (d MySQLDriver) OpenConnector(dsn string) (driver.Connector, error) {
 	if err != nil {
 		return nil, err
 	}
-	return &connector{
-		cfg: cfg,
-	}, nil
+	return newConnector(cfg), nil
 }