Fix issue where a timeout closes the connection

As part of CASSGO-12 which was supposedly just removing deprecated code, the driver now closes connections when a timeout occurs which was unintended. This patch fixes this issue.

patch by João Reis; reviewed by Bohdan Siryk and Lukasz Antoniak for CASSGO-87

Author: joao-r-reis

CHANGELOG.md

@@ -67,6 +67,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 #### 2.0.0
 
+- Driver closes connection when timeout occurs (CASSGO-87)
 - Do not set beta protocol flag when using v5 (CASSGO-88)
 
 #### 2.0.0-rc1

conn.go

@@ -199,8 +199,6 @@ type Conn struct {
 	ctx    context.Context
 	cancel context.CancelFunc
 
-	timeouts int64
-
 	logger StructuredLogger
 }
 
@@ -753,12 +751,6 @@ func (c *Conn) releaseStream(call *callReq) {
 	}
 }
 
-func (c *Conn) handleTimeout() {
-	if atomic.AddInt64(&c.timeouts, 1) > 0 {
-		c.closeWithError(ErrTooManyTimeouts)
-	}
-}
-
 func (c *Conn) recvSegment(ctx context.Context) error {
 	var (
 		frame           []byte
@@ -1339,7 +1331,6 @@ func (c *Conn) execInternal(ctx context.Context, req frameBuilder, tracer Tracer
 		close(call.timeout)
 		c.logger.Debug("Request timed out on connection.",
 			newLogFieldString("host_id", c.host.HostID()), newLogFieldIp("addr", c.host.ConnectAddress()))
-		c.handleTimeout()
 		return nil, ErrTimeoutNoResponse
 	case <-ctxDone:
 		c.logger.Debug("Request failed because context elapsed out on connection.",
@@ -2004,9 +1995,13 @@ func (c *Conn) awaitSchemaAgreement(ctx context.Context) (err error) {
 }
 
 var (
-	ErrQueryArgLength    = errors.New("gocql: query argument length mismatch")
 	ErrTimeoutNoResponse = errors.New("gocql: no response received from cassandra within timeout period")
-	ErrTooManyTimeouts   = errors.New("gocql: too many query timeouts on the connection")
 	ErrConnectionClosed  = errors.New("gocql: connection closed waiting for response")
 	ErrNoStreams         = errors.New("gocql: no streams available on connection")
+
+	// Deprecated: TimeoutLimit was removed so this is never returned by the driver now
+	ErrTooManyTimeouts = errors.New("gocql: too many query timeouts on the connection")
+
+	// Deprecated: Never returned by the driver
+	ErrQueryArgLength = errors.New("gocql: query argument length mismatch")
 )