client: Have SetCapability() return an error for unsupported caps

client/auth.go

@@ -14,6 +14,19 @@ import (
 
 const defaultAuthPluginName = mysql.AUTH_NATIVE_PASSWORD
 
+var optionalCapabilities = []uint32{
+	mysql.CLIENT_FOUND_ROWS,
+	mysql.CLIENT_IGNORE_SPACE,
+	mysql.CLIENT_MULTI_STATEMENTS,
+	mysql.CLIENT_MULTI_RESULTS,
+	mysql.CLIENT_PS_MULTI_RESULTS,
+	mysql.CLIENT_CONNECT_ATTRS,
+	mysql.CLIENT_COMPRESS,
+	mysql.CLIENT_ZSTD_COMPRESSION_ALGORITHM,
+	mysql.CLIENT_LOCAL_FILES,
+	mysql.CLIENT_SESSION_TRACK,
+}
+
 // defines the supported auth plugins
 var supportedAuthPlugins = []string{mysql.AUTH_NATIVE_PASSWORD, mysql.AUTH_SHA256_PASSWORD, mysql.AUTH_CACHING_SHA2_PASSWORD, mysql.AUTH_MARIADB_ED25519}
 
@@ -214,11 +227,9 @@ func (c *Conn) writeAuthHandshake() error {
 	// Adjust client capability flags on specific client requests
 	// Only flags that would make any sense setting and aren't handled elsewhere
 	// in the library are supported here
-	capability |= c.ccaps&mysql.CLIENT_FOUND_ROWS | c.ccaps&mysql.CLIENT_IGNORE_SPACE |
-		c.ccaps&mysql.CLIENT_MULTI_STATEMENTS | c.ccaps&mysql.CLIENT_MULTI_RESULTS |
-		c.ccaps&mysql.CLIENT_PS_MULTI_RESULTS | c.ccaps&mysql.CLIENT_CONNECT_ATTRS |
-		c.ccaps&mysql.CLIENT_COMPRESS | c.ccaps&mysql.CLIENT_ZSTD_COMPRESSION_ALGORITHM |
-		c.ccaps&mysql.CLIENT_LOCAL_FILES | c.ccaps&mysql.CLIENT_SESSION_TRACK
+	for _, optionalCap := range optionalCapabilities {
+		capability |= c.ccaps & optionalCap
+	}
 
 	capability &^= c.clientExplicitOffCaps
 

client/client_test.go

@@ -92,8 +92,7 @@ func (s *clientTestSuite) TestConn_Ping() {
 func (s *clientTestSuite) TestConn_Compress() {
 	addr := fmt.Sprintf("%s:%s", *test_util.MysqlHost, s.port)
 	conn, err := Connect(addr, *testUser, *testPassword, "", func(conn *Conn) error {
-		conn.SetCapability(mysql.CLIENT_COMPRESS)
-		return nil
+		return conn.SetCapability(mysql.CLIENT_COMPRESS)
 	})
 	require.NoError(s.T(), err)
 
@@ -115,38 +114,28 @@ func (s *clientTestSuite) TestConn_NoDeprecateEOF() {
 
 func (s *clientTestSuite) TestConn_SetCapability() {
 	caps := []uint32{
-		mysql.CLIENT_LONG_PASSWORD,
 		mysql.CLIENT_FOUND_ROWS,
-		mysql.CLIENT_LONG_FLAG,
-		mysql.CLIENT_CONNECT_WITH_DB,
-		mysql.CLIENT_NO_SCHEMA,
-		mysql.CLIENT_COMPRESS,
-		mysql.CLIENT_ODBC,
-		mysql.CLIENT_LOCAL_FILES,
 		mysql.CLIENT_IGNORE_SPACE,
-		mysql.CLIENT_PROTOCOL_41,
-		mysql.CLIENT_INTERACTIVE,
-		mysql.CLIENT_SSL,
-		mysql.CLIENT_IGNORE_SIGPIPE,
-		mysql.CLIENT_TRANSACTIONS,
-		mysql.CLIENT_RESERVED,
-		mysql.CLIENT_SECURE_CONNECTION,
 		mysql.CLIENT_MULTI_STATEMENTS,
 		mysql.CLIENT_MULTI_RESULTS,
 		mysql.CLIENT_PS_MULTI_RESULTS,
-		mysql.CLIENT_PLUGIN_AUTH,
 		mysql.CLIENT_CONNECT_ATTRS,
-		mysql.CLIENT_PLUGIN_AUTH_LENENC_CLIENT_DATA,
-		mysql.CLIENT_DEPRECATE_EOF,
+		mysql.CLIENT_COMPRESS,
+		mysql.CLIENT_ZSTD_COMPRESSION_ALGORITHM,
+		mysql.CLIENT_LOCAL_FILES,
 	}
 
 	for _, capI := range caps {
 		require.False(s.T(), s.c.ccaps&capI > 0)
-		s.c.SetCapability(capI)
+		err := s.c.SetCapability(capI)
+		require.NoError(s.T(), err, "capability: %d", capI)
 		require.True(s.T(), s.c.ccaps&capI > 0)
 		s.c.UnsetCapability(capI)
 		require.False(s.T(), s.c.ccaps&capI > 0)
 	}
+
+	err := s.c.SetCapability(mysql.CLIENT_REMEMBER_OPTIONS + 10)
+	require.Error(s.T(), err)
 }
 
 // NOTE for MySQL 5.5 and 5.6, server side has to config SSL to pass the TLS test, otherwise, it will throw error that

client/conn.go

@@ -9,6 +9,7 @@ import (
 	"net"
 	"runtime"
 	"runtime/debug"
+	"slices"
 	"strings"
 	"time"
 
@@ -238,9 +239,13 @@ func (c *Conn) Ping() error {
 }
 
 // SetCapability marks the specified flag as explicitly enabled by the client.
-func (c *Conn) SetCapability(cap uint32) {
+func (c *Conn) SetCapability(cap uint32) error {
+	if !slices.Contains(optionalCapabilities, cap) {
+		return errors.New("unsupported or unknown capability")
+	}
 	c.ccaps |= cap
 	c.clientExplicitOffCaps &^= cap
+	return nil
 }
 
 // UnsetCapability marks the specified flag as explicitly disabled by the client.

client/conn_test.go

@@ -30,9 +30,9 @@ func (s *connTestSuite) SetupSuite() {
 	addr := fmt.Sprintf("%s:%s", *test_util.MysqlHost, s.port)
 	s.c, err = Connect(addr, *testUser, *testPassword, "", func(c *Conn) error {
 		// required for the ExecuteMultiple test
-		c.SetCapability(mysql.CLIENT_MULTI_STATEMENTS)
+		err = c.SetCapability(mysql.CLIENT_MULTI_STATEMENTS)
 		c.SetAttributes(map[string]string{"attrtest": "attrvalue"})
-		return nil
+		return err
 	})
 	require.NoError(s.T(), err)
 

driver/driver_options.go

@@ -38,9 +38,9 @@ func WriteTimeoutOption(c *client.Conn, value string) error {
 func CompressOption(c *client.Conn, value string) error {
 	switch value {
 	case "zlib":
-		c.SetCapability(mysql.CLIENT_COMPRESS)
+		_ = c.SetCapability(mysql.CLIENT_COMPRESS)
 	case "zstd":
-		c.SetCapability(mysql.CLIENT_ZSTD_COMPRESSION_ALGORITHM)
+		_ = c.SetCapability(mysql.CLIENT_ZSTD_COMPRESSION_ALGORITHM)
 	case "uncompressed":
 		c.UnsetCapability(mysql.CLIENT_COMPRESS)
 		c.UnsetCapability(mysql.CLIENT_ZSTD_COMPRESSION_ALGORITHM)