Update based on review

Author: dveeden

client/conn.go

@@ -508,19 +508,20 @@ func (c *Conn) exec(query string) (*Result, error) {
 // https://dev.mysql.com/doc/dev/mysql-server/latest/page_protocol_com_query.html
 func (c *Conn) execSend(query string) error {
 	var buf bytes.Buffer
+	defer clear(c.queryAttributes)
 
-	if c.includeLine >= 0 {
-		_, file, line, ok := runtime.Caller(c.includeLine)
-		if ok {
-			lineAttr := QueryAttribute{
-				Name:  "_line",
-				Value: fmt.Sprintf("%s:%d", file, line),
+	if c.capability&CLIENT_QUERY_ATTRIBUTES > 0 {
+		if c.includeLine >= 0 {
+			_, file, line, ok := runtime.Caller(c.includeLine)
+			if ok {
+				lineAttr := QueryAttribute{
+					Name:  "_line",
+					Value: fmt.Sprintf("%s:%d", file, line),
+				}
+				c.queryAttributes = append(c.queryAttributes, lineAttr)
 			}
-			c.queryAttributes = append(c.queryAttributes, lineAttr)
 		}
-	}
 
-	if c.capability&CLIENT_QUERY_ATTRIBUTES > 0 {
 		numParams := len(c.queryAttributes)
 		buf.Write(PutLengthEncodedInt(uint64(numParams)))
 		buf.WriteByte(0x1) // parameter_set_count, unused
@@ -548,7 +549,6 @@ func (c *Conn) execSend(query string) error {
 	if err := c.writeCommandBuf(COM_QUERY, buf.Bytes()); err != nil {
 		return errors.Trace(err)
 	}
-	c.queryAttributes = nil
 
 	return nil
 }

client/stmt.go

@@ -59,13 +59,14 @@ func (s *Stmt) Close() error {
 
 // https://dev.mysql.com/doc/dev/mysql-server/latest/page_protocol_com_stmt_execute.html
 func (s *Stmt) write(args ...interface{}) error {
+	defer clear(s.conn.queryAttributes)
 	paramsNum := s.params
 
 	if len(args) != paramsNum {
 		return fmt.Errorf("argument mismatch, need %d but got %d", s.params, len(args))
 	}
 
-	if s.conn.includeLine >= 0 {
+	if (s.conn.capability&CLIENT_QUERY_ATTRIBUTES > 0) && (s.conn.includeLine >= 0) {
 		_, file, line, ok := runtime.Caller(s.conn.includeLine)
 		if ok {
 			lineAttr := QueryAttribute{
@@ -227,7 +228,6 @@ func (s *Stmt) write(args ...interface{}) error {
 	}
 
 	s.conn.ResetSequence()
-	s.conn.queryAttributes = nil
 
 	return s.conn.WritePacket(data.Bytes())
 }

mysql/queryattributes.go

@@ -8,6 +8,8 @@ import (
 
 // Query Attributes in MySQL are key/value pairs passed along with COM_QUERY or COM_STMT_EXECUTE
 //
+// Supported Value types: string, uint64
+//
 // Resources:
 // - https://dev.mysql.com/doc/refman/8.4/en/query-attributes.html
 // - https://github.com/mysql/mysql-server/blob/trunk/include/mysql/components/services/mysql_query_attributes.h

server/stmt.go

@@ -118,16 +118,13 @@ func (c *Conn) handleStmtExecute(data []byte) (*Result, error) {
 
 	// Test for unsupported flags in the remaining 4 bits.
 	if flag&CURSOR_TYPE_READ_ONLY > 0 {
-		return nil, NewError(ER_UNKNOWN_ERROR,
-			fmt.Sprintf("unsupported flag %s", "CURSOR_TYPE_READ_ONLY"))
+		return nil, NewError(ER_UNKNOWN_ERROR, "unsupported flag CURSOR_TYPE_READ_ONLY")
 	}
 	if flag&CURSOR_TYPE_FOR_UPDATE > 0 {
-		return nil, NewError(ER_UNKNOWN_ERROR,
-			fmt.Sprintf("unsupported flag %s", "CURSOR_TYPE_FOR_UPDATE"))
+		return nil, NewError(ER_UNKNOWN_ERROR, "unsupported flag CURSOR_TYPE_FOR_UPDATE")
 	}
 	if flag&CURSOR_TYPE_SCROLLABLE > 0 {
-		return nil, NewError(ER_UNKNOWN_ERROR,
-			fmt.Sprintf("unsupported flag %s", "CURSOR_TYPE_SCROLLABLE"))
+		return nil, NewError(ER_UNKNOWN_ERROR, "unsupported flag CURSOR_TYPE_SCROLLABLE")
 	}
 
 	//skip iteration-count, always 1