fix: empty value in unix and unixnano binding

binding/form_mapping.go

@@ -397,6 +397,11 @@ func setTimeField(val string, structField reflect.StructField, value reflect.Val
 		timeFormat = time.RFC3339
 	}
 
+	if val == "" {
+		value.Set(reflect.ValueOf(time.Time{}))
+		return nil
+	}
+
 	switch tf := strings.ToLower(timeFormat); tf {
 	case "unix", "unixnano":
 		tv, err := strconv.ParseInt(val, 10, 64)
@@ -414,11 +419,6 @@ func setTimeField(val string, structField reflect.StructField, value reflect.Val
 		return nil
 	}
 
-	if val == "" {
-		value.Set(reflect.ValueOf(time.Time{}))
-		return nil
-	}
-
 	l := time.Local
 	if isUTC, _ := strconv.ParseBool(structField.Tag.Get("time_utc")); isUTC {
 		l = time.UTC

binding/form_mapping_test.go

@@ -635,3 +635,25 @@ func TestMappingCustomArrayForm(t *testing.T) {
 	expected, _ := convertTo(val)
 	assert.EqualValues(t, expected, s.FileData)
 }
+
+func TestMappingTimeUnixAndUnixNano(t *testing.T) {
+	var s struct {
+		Unix               time.Time `time_format:"unix"`
+		UnixNano           time.Time `time_format:"unixnano"`
+		EmptyValueUnix     time.Time `time_format:"unix"`
+		EmptyValueUnixNano time.Time `time_format:"unixnano"`
+	}
+
+	err := mapForm(&s, map[string][]string{
+		"Unix":               {"1548000000"},
+		"UnixNano":           {"1548000000000000000"},
+		"EmptyValue":         {""},
+		"EmptyValueUnixNano": {""},
+	})
+	require.NoError(t, err)
+
+	assert.Equal(t, "2019-01-20 16:00:00 +0000 UTC", s.Unix.UTC().String())
+	assert.Equal(t, "2019-01-20 16:00:00 +0000 UTC", s.UnixNano.UTC().String())
+	assert.Zero(t, s.EmptyValueUnix)
+	assert.Zero(t, s.EmptyValueUnixNano)
+}