Address staticcheck warnings in prepared statement

Merged prepared statement code changes did not take into account
staticcheck warnings. This PR addresses those warnings.

Signed-off-by: Saif Alharthi <saif@saifalharthi.me>

go/mysql/query.go

@@ -555,7 +555,7 @@ func (c *Conn) parseComStmtExecute(prepareData map[uint32]*PrepareData, data []b
 		}
 	}
 
-	newParamsBoundFlag, pos, ok := readByte(payload, pos)
+	newParamsBoundFlag, pos, _ := readByte(payload, pos)
 	if newParamsBoundFlag == 0x01 {
 		var mysqlType, flags byte
 		for i := uint16(0); i < prepare.ParamsCount; i++ {
@@ -1020,7 +1020,7 @@ func (c *Conn) writePrepare(fld []*querypb.Field, prepare *PrepareData) error {
 	pos = writeUint16(data, pos, uint16(columnCount))
 	pos = writeUint16(data, pos, uint16(paramsCount))
 	pos = writeByte(data, pos, 0x00)
-	pos = writeUint16(data, pos, 0x0000)
+	writeUint16(data, pos, 0x0000)
 
 	if err := c.writeEphemeralPacket(); err != nil {
 		return err
@@ -1244,7 +1244,7 @@ func val2MySQL(v sqltypes.Value) ([]byte, error) {
 			pos = writeByte(out, pos, byte(hour))
 			pos = writeByte(out, pos, byte(minute))
 			pos = writeByte(out, pos, byte(second))
-			pos = writeUint32(out, pos, uint32(microSecond))
+			writeUint32(out, pos, uint32(microSecond))
 		} else if len(v.Raw()) > 10 {
 			out = make([]byte, 1+7)
 			out[pos] = 0x07
@@ -1278,7 +1278,7 @@ func val2MySQL(v sqltypes.Value) ([]byte, error) {
 			pos = writeByte(out, pos, byte(day))
 			pos = writeByte(out, pos, byte(hour))
 			pos = writeByte(out, pos, byte(minute))
-			pos = writeByte(out, pos, byte(second))
+			writeByte(out, pos, byte(second))
 		} else if len(v.Raw()) > 0 {
 			out = make([]byte, 1+4)
 			out[pos] = 0x04
@@ -1297,7 +1297,7 @@ func val2MySQL(v sqltypes.Value) ([]byte, error) {
 			}
 			pos = writeUint16(out, pos, uint16(year))
 			pos = writeByte(out, pos, byte(month))
-			pos = writeByte(out, pos, byte(day))
+			writeByte(out, pos, byte(day))
 		} else {
 			out = make([]byte, 1)
 			out[pos] = 0x00
@@ -1367,7 +1367,7 @@ func val2MySQL(v sqltypes.Value) ([]byte, error) {
 			if err != nil {
 				return []byte{}, err
 			}
-			pos = writeUint32(out, pos, uint32(microSeconds))
+			writeUint32(out, pos, uint32(microSeconds))
 		} else if len(v.Raw()) > 0 {
 			out = make([]byte, 1+8)
 			out[pos] = 0x08
@@ -1412,7 +1412,7 @@ func val2MySQL(v sqltypes.Value) ([]byte, error) {
 			pos = writeUint32(out, pos, uint32(days))
 			pos = writeByte(out, pos, byte(hours))
 			pos = writeByte(out, pos, byte(minutes))
-			pos = writeByte(out, pos, byte(seconds))
+			writeByte(out, pos, byte(seconds))
 		} else {
 			err := fmt.Errorf("incorrect time value")
 			return []byte{}, err

go/vt/vtgate/executor_dml_test.go

@@ -1771,8 +1771,7 @@ func TestUpdateEqualWithPrepare(t *testing.T) {
 		t.Error(err)
 	}
 
-	wantQueries := []*querypb.BoundQuery{}
-	wantQueries = nil
+	var wantQueries []*querypb.BoundQuery
 
 	if !reflect.DeepEqual(sbclookup.Queries, wantQueries) {
 		t.Errorf("sbclookup.Queries: %+v, want %+v\n", sbclookup.Queries, wantQueries)
@@ -1799,8 +1798,7 @@ func TestInsertShardedWithPrepare(t *testing.T) {
 		t.Error(err)
 	}
 
-	wantQueries := []*querypb.BoundQuery{}
-	wantQueries = nil
+	var wantQueries []*querypb.BoundQuery
 
 	if !reflect.DeepEqual(sbc1.Queries, wantQueries) {
 		t.Errorf("sbc1.Queries:\n%+v, want\n%+v\n", sbc1.Queries, wantQueries)
@@ -1822,8 +1820,8 @@ func TestDeleteEqualWithPrepare(t *testing.T) {
 	if err != nil {
 		t.Error(err)
 	}
-	wantQueries := []*querypb.BoundQuery{}
-	wantQueries = nil
+
+	var wantQueries []*querypb.BoundQuery
 
 	if !reflect.DeepEqual(sbc.Queries, wantQueries) {
 		t.Errorf("sbc.Queries:\n%+v, want\n%+v\n", sbc.Queries, wantQueries)