Merge pull request #721 from btoonk/btoonk/proxy-null

fix: return null values properly in proxy mode

Author: lance6716

server/resp.go

@@ -182,11 +182,16 @@ func (c *Conn) writeFieldList(fs []*Field, data []byte) error {
 func (c *Conn) writeFieldValues(fv []FieldValue) error {
 	data := make([]byte, 4, 1024)
 	for _, v := range fv {
-		tv, err := FormatTextValue(v.Value())
-		if err != nil {
-			return err
+		if v.Value() == nil {
+			// NULL value is encoded as 0xfb here
+			data = append(data, []byte{0xfb}...)
+		} else {
+			tv, err := FormatTextValue(v.Value())
+			if err != nil {
+				return err
+			}
+			data = append(data, PutLengthEncodedString(tv)...)
 		}
-		data = append(data, PutLengthEncodedString(tv)...)
 	}
 
 	return c.WritePacket(data)

server/resp_test.go

@@ -189,3 +189,43 @@ func (t *respConnTestSuite) TestConnWriteFieldList(c *check.C) {
 	c.Assert(clientConn.WriteBuffered[:27], check.BytesEquals, []byte{23, 0, 0, 0, 3, 100, 101, 102, 0, 0, 0, 1, 'c', 0, 12, 33, 0, 0, 0, 0, 0, 253, 0, 0, 0, 0, 0})
 	c.Assert(clientConn.WriteBuffered[27:], check.BytesEquals, []byte{1, 0, 0, 1, mysql.EOF_HEADER})
 }
+
+func (t *respConnTestSuite) TestConnWriteFieldValues(c *check.C) {
+	clientConn := &mockconn.MockConn{MultiWrite: true}
+	conn := &Conn{Conn: packet.NewConn(clientConn)}
+
+	r, err := mysql.BuildSimpleTextResultset([]string{"c"}, [][]interface{}{
+		[]interface{}{"d"},
+		[]interface{}{nil},
+	})
+
+	c.Assert(err, check.IsNil)
+	err = conn.writeFieldList(r.Fields, nil)
+	c.Assert(err, check.IsNil)
+
+	// fields and EOF
+	c.Assert(clientConn.WriteBuffered[:27], check.BytesEquals, []byte{23, 0, 0, 0, 3, 100, 101, 102, 0, 0, 0, 1, 'c', 0, 12, 33, 0, 0, 0, 0, 0, 253, 0, 0, 0, 0, 0})
+	c.Assert(clientConn.WriteBuffered[27:32], check.BytesEquals, []byte{1, 0, 0, 1, mysql.EOF_HEADER})
+
+	r.Values = make([][]mysql.FieldValue, len(r.RowDatas))
+	for i := range r.Values {
+		r.Values[i], err = r.RowDatas[i].Parse(r.Fields, false, r.Values[i])
+
+		c.Assert(err, check.IsNil)
+
+		err = conn.writeFieldValues(r.Values[i])
+		c.Assert(err, check.IsNil)
+	}
+
+	err = conn.writeEOF()
+	c.Assert(err, check.IsNil)
+
+	// first row
+	c.Assert(clientConn.WriteBuffered[32:38], check.BytesEquals, []byte{2, 0, 0, 2, 1, 'd'})
+
+	// second row with NULL value
+	c.Assert(clientConn.WriteBuffered[38:43], check.BytesEquals, []byte{1, 0, 0, 3, 251})
+
+	// EOF
+	c.Assert(clientConn.WriteBuffered[43:], check.BytesEquals, []byte{1, 0, 0, 4, mysql.EOF_HEADER})
+}