Merge pull request #455 from dolthub/aaron/mysql-conn-ephemeral-packet-recycle-on-error

go/mysql: Add some recycleWritePacket calls on error returning paths where the ephemeral packet was not previously returned.

Author: reltuk

go/mysql/client.go

@@ -725,6 +725,7 @@ func (c *Conn) writeHandshakeResponse41(capabilities uint32, scrambledPassword [
 
 	// Sanity-check the length.
 	if pos != len(data) {
+		c.recycleWritePacket()
 		return NewSQLError(CRMalformedPacket, SSUnknownSQLState, "writeHandshakeResponse41: only packed %v bytes, out of %v allocated", pos, len(data))
 	}
 
@@ -791,6 +792,7 @@ func (c *Conn) writeClearTextPassword(params *ConnParams) error {
 	pos = writeNullString(data, pos, params.Pass)
 	// Sanity check.
 	if pos != len(data) {
+		c.recycleWritePacket()
 		return vterrors.Errorf(vtrpcpb.Code_INTERNAL, "error building ClearTextPassword packet: got %v bytes expected %v", pos, len(data))
 	}
 	return c.writeEphemeralPacket()
@@ -804,6 +806,7 @@ func (c *Conn) writeScrambledPassword(scrambledPassword []byte) error {
 	pos += copy(data[pos:], scrambledPassword)
 	// Sanity check.
 	if pos != len(data) {
+		c.recycleWritePacket()
 		return vterrors.Errorf(vtrpcpb.Code_INTERNAL, "error building %v packet: got %v bytes expected %v", c.authPluginName, pos, len(data))
 	}
 	return c.writeEphemeralPacket()

go/mysql/conn.go

@@ -777,6 +777,7 @@ func (c *Conn) writeErrorPacket(errorCode uint16, sqlState string, format string
 		sqlState = SSUnknownSQLState
 	}
 	if len(sqlState) != 5 {
+		c.recycleWritePacket()
 		panic("sqlState has to be 5 characters long")
 	}
 	pos = writeEOFString(data, pos, sqlState)

go/mysql/query.go

@@ -1021,6 +1021,7 @@ func (c *Conn) writeColumnDefinition(field *querypb.Field, withDefaults bool) er
 	}
 
 	if pos != len(data) {
+		c.recycleWritePacket()
 		return vterrors.Errorf(vtrpc.Code_INTERNAL, "packing of column definition used %v bytes instead of %v", pos, len(data))
 	}
 
@@ -1051,6 +1052,7 @@ func (c *Conn) writeRow(row []sqltypes.Value) error {
 	}
 
 	if pos != length {
+		c.recycleWritePacket()
 		return vterrors.Errorf(vtrpc.Code_INTERNAL, "packet row: got %v bytes but expected %v", pos, length)
 	}
 
@@ -1235,6 +1237,7 @@ func (c *Conn) writeBinaryRow(fields []*querypb.Field, row []sqltypes.Value) err
 	}
 
 	if pos != length {
+		c.recycleWritePacket()
 		return fmt.Errorf("internal error packet row: got %v bytes but expected %v", pos, length)
 	}
 

go/mysql/server.go

@@ -713,6 +713,7 @@ func (c *Conn) writeHandshakeV10(serverVersion string, authServer AuthServer, en
 	// auth method is also mysql_native_password or caching_sha2_password.
 	pluginData, err := NewSalt()
 	if err != nil {
+		c.recycleWritePacket()
 		return nil, err
 	}
 	// Plugin data is always defined as having a trailing NULL
@@ -751,6 +752,7 @@ func (c *Conn) writeHandshakeV10(serverVersion string, authServer AuthServer, en
 
 	// Sanity check.
 	if pos != len(data) {
+		c.recycleWritePacket()
 		return nil, vterrors.Errorf(vtrpc.Code_INTERNAL, "error building Handshake packet: got %v bytes expected %v", pos, len(data))
 	}
 
@@ -961,6 +963,7 @@ func (c *Conn) writeAuthSwitchRequest(pluginName string, pluginData []byte) erro
 
 	// Sanity check.
 	if pos != len(data) {
+		c.recycleWritePacket()
 		return vterrors.Errorf(vtrpc.Code_INTERNAL, "error building AuthSwitchRequestPacket packet: got %v bytes expected %v", pos, len(data))
 	}
 	return c.writeEphemeralPacket()