cherry pick pingcap#32896 to release-5.2

Signed-off-by: ti-srebot <ti-srebot@pingcap.com>

expression/builtin_time_test.go

@@ -1584,6 +1584,7 @@ func (s *testEvaluatorSuite) TestTimeDiff(c *C) {
 		fsp        int8
 		getWarning bool
 	}{
+<<<<<<< HEAD
 		{[]interface{}{"2000:01:01 00:00:00", "2000:01:01 00:00:00.000001"}, "-00:00:00.000001", false, 6, false},
 		{[]interface{}{"2008-12-31 23:59:59.000001", "2008-12-30 01:01:01.000002"}, "46:58:57.999999", false, 6, false},
 		{[]interface{}{"2016-12-00 12:00:00", "2016-12-01 12:00:00"}, "-24:00:00", false, 0, false},
@@ -1596,6 +1597,21 @@ func (s *testEvaluatorSuite) TestTimeDiff(c *C) {
 		preWarningCnt := s.ctx.GetSessionVars().StmtCtx.WarningCount()
 		f, err := newFunctionForTest(s.ctx, ast.TimeDiff, s.primitiveValsToConstants(t.args)...)
 		c.Assert(err, IsNil)
+=======
+		{[]interface{}{"2000:01:01 00:00:00", "2000:01:01 00:00:00.000001"}, "-00:00:00.000001", false, 6, 17, false},
+		{[]interface{}{"2008-12-31 23:59:59.000001", "2008-12-30 01:01:01.000002"}, "46:58:57.999999", false, 6, 17, false},
+		{[]interface{}{"2016-12-00 12:00:00", "2016-12-01 12:00:00"}, "-24:00:00", false, 0, 10, false},
+		{[]interface{}{"10:10:10", "10:9:0"}, "00:01:10", false, 0, 10, false},
+		{[]interface{}{"2016-12-00 12:00:00", "10:9:0"}, "", true, 0, 10, false},
+		{[]interface{}{"2016-12-00 12:00:00", ""}, "", true, 0, 10, true},
+		{[]interface{}{"00:00:00.000000", "00:00:00.000001"}, "-00:00:00.000001", false, 6, 17, false},
+	}
+
+	for _, c := range tests {
+		preWarningCnt := ctx.GetSessionVars().StmtCtx.WarningCount()
+		f, err := newFunctionForTest(ctx, ast.TimeDiff, primitiveValsToConstants(ctx, c.args)...)
+		require.NoError(t, err)
+>>>>>>> d8fbad38a... expression, types: fix StrToDuration result (#32896)
 		tp := f.GetType()
 		c.Assert(tp.Tp, Equals, mysql.TypeDuration)
 		c.Assert(tp.Charset, Equals, charset.CharsetBin)

types/convert.go

@@ -314,6 +314,9 @@ func StrToDuration(sc *stmtctx.StatementContext, str string, fsp int8) (d Durati
 	if length > 0 && str[0] == '-' {
 		length--
 	}
+	if n := strings.IndexByte(str, '.'); n >= 0 {
+		length = length - len(str[n:])
+	}
 	// Timestamp format is 'YYYYMMDDHHMMSS' or 'YYMMDDHHMMSS', which length is 12.
 	// See #3923, it explains what we do here.
 	if length >= 12 {

types/convert_test.go

@@ -1124,6 +1124,8 @@ func (s *testTypeConvertSuite) TestStrToDuration(c *C) {
 		{"20190101180000", 6, false},
 		{"20190101180000", 1, false},
 		{"20190101181234", 3, false},
+		{"00:00:00.000000", 6, true},
+		{"00:00:00", 0, true},
 	}
 	for _, tt := range tests {
 		_, _, isDuration, err := StrToDuration(sc, tt.str, tt.fsp)