Support translating field errors when field is of kind reflect.Ptr

Previously, if fields were of kind `reflect.Ptr`, the translation of
validation errors used the default string, resulting in unexpected
output.

Now the default translations use the field's `Elem()` kind (for example
for `*string` the `Elem()` is `string`), resulting in much more natural
output.

translations/en/en.go

@@ -69,6 +69,7 @@ func RegisterDefaultTranslations(v *validator.Validate, trans ut.Translator) (er
 				var t string
 
 				var digits uint64
+				var kind reflect.Kind
 
 				if idx := strings.Index(fe.Param(), "."); idx != -1 {
 					digits = uint64(len(fe.Param()[idx+1:]))
@@ -79,7 +80,12 @@ func RegisterDefaultTranslations(v *validator.Validate, trans ut.Translator) (er
 					goto END
 				}
 
-				switch fe.Kind() {
+				kind = fe.Kind()
+				if kind == reflect.Ptr {
+					kind = fe.Type().Elem().Kind()
+				}
+
+				switch kind {
 				case reflect.String:
 
 					var c string
@@ -154,6 +160,7 @@ func RegisterDefaultTranslations(v *validator.Validate, trans ut.Translator) (er
 				var t string
 
 				var digits uint64
+				var kind reflect.Kind
 
 				if idx := strings.Index(fe.Param(), "."); idx != -1 {
 					digits = uint64(len(fe.Param()[idx+1:]))
@@ -164,7 +171,12 @@ func RegisterDefaultTranslations(v *validator.Validate, trans ut.Translator) (er
 					goto END
 				}
 
-				switch fe.Kind() {
+				kind = fe.Kind()
+				if kind == reflect.Ptr {
+					kind = fe.Type().Elem().Kind()
+				}
+
+				switch kind {
 				case reflect.String:
 
 					var c string
@@ -239,6 +251,7 @@ func RegisterDefaultTranslations(v *validator.Validate, trans ut.Translator) (er
 				var t string
 
 				var digits uint64
+				var kind reflect.Kind
 
 				if idx := strings.Index(fe.Param(), "."); idx != -1 {
 					digits = uint64(len(fe.Param()[idx+1:]))
@@ -249,7 +262,12 @@ func RegisterDefaultTranslations(v *validator.Validate, trans ut.Translator) (er
 					goto END
 				}
 
-				switch fe.Kind() {
+				kind = fe.Kind()
+				if kind == reflect.Ptr {
+					kind = fe.Type().Elem().Kind()
+				}
+
+				switch kind {
 				case reflect.String:
 
 					var c string
@@ -359,6 +377,7 @@ func RegisterDefaultTranslations(v *validator.Validate, trans ut.Translator) (er
 				var t string
 				var f64 float64
 				var digits uint64
+				var kind reflect.Kind
 
 				fn := func() (err error) {
 
@@ -371,7 +390,12 @@ func RegisterDefaultTranslations(v *validator.Validate, trans ut.Translator) (er
 					return
 				}
 
-				switch fe.Kind() {
+				kind = fe.Kind()
+				if kind == reflect.Ptr {
+					kind = fe.Type().Elem().Kind()
+				}
+
+				switch kind {
 				case reflect.String:
 
 					var c string
@@ -472,6 +496,7 @@ func RegisterDefaultTranslations(v *validator.Validate, trans ut.Translator) (er
 				var t string
 				var f64 float64
 				var digits uint64
+				var kind reflect.Kind
 
 				fn := func() (err error) {
 
@@ -484,7 +509,12 @@ func RegisterDefaultTranslations(v *validator.Validate, trans ut.Translator) (er
 					return
 				}
 
-				switch fe.Kind() {
+				kind = fe.Kind()
+				if kind == reflect.Ptr {
+					kind = fe.Type().Elem().Kind()
+				}
+
+				switch kind {
 				case reflect.String:
 
 					var c string
@@ -585,6 +615,7 @@ func RegisterDefaultTranslations(v *validator.Validate, trans ut.Translator) (er
 				var t string
 				var f64 float64
 				var digits uint64
+				var kind reflect.Kind
 
 				fn := func() (err error) {
 
@@ -597,7 +628,12 @@ func RegisterDefaultTranslations(v *validator.Validate, trans ut.Translator) (er
 					return
 				}
 
-				switch fe.Kind() {
+				kind = fe.Kind()
+				if kind == reflect.Ptr {
+					kind = fe.Type().Elem().Kind()
+				}
+
+				switch kind {
 				case reflect.String:
 
 					var c string
@@ -698,6 +734,7 @@ func RegisterDefaultTranslations(v *validator.Validate, trans ut.Translator) (er
 				var t string
 				var f64 float64
 				var digits uint64
+				var kind reflect.Kind
 
 				fn := func() (err error) {
 
@@ -710,7 +747,12 @@ func RegisterDefaultTranslations(v *validator.Validate, trans ut.Translator) (er
 					return
 				}
 
-				switch fe.Kind() {
+				kind = fe.Kind()
+				if kind == reflect.Ptr {
+					kind = fe.Type().Elem().Kind()
+				}
+
+				switch kind {
 				case reflect.String:
 
 					var c string

translations/en/en_test.go

@@ -129,6 +129,13 @@ func TestTranslations(t *testing.T) {
 		UinxAddr          string    `validate:"unix_addr"` // can't fail from within Go's net package currently, but maybe in the future
 		MAC               string    `validate:"mac"`
 		IsColor           string    `validate:"iscolor"`
+		StrPtrMinLen      *string   `validate:"min=10"`
+		StrPtrMaxLen      *string   `validate:"max=1"`
+		StrPtrLen         *string   `validate:"len=2"`
+		StrPtrLt          *string   `validate:"lt=1"`
+		StrPtrLte         *string   `validate:"lte=1"`
+		StrPtrGt          *string   `validate:"gt=10"`
+		StrPtrGte         *string   `validate:"gte=10"`
 	}
 
 	var test Test
@@ -171,6 +178,10 @@ func TestTranslations(t *testing.T) {
 
 	test.MultiByte = "1234feerf"
 
+	s := "toolong"
+	test.StrPtrMaxLen = &s
+	test.StrPtrLen = &s
+
 	err = validate.Struct(test)
 	NotEqual(t, err, nil)
 
@@ -565,6 +576,34 @@ func TestTranslations(t *testing.T) {
 			ns:       "Test.RequiredMultiple",
 			expected: "RequiredMultiple is a required field",
 		},
+		{
+			ns:       "Test.StrPtrMinLen",
+			expected: "StrPtrMinLen must be at least 10 characters in length",
+		},
+		{
+			ns:       "Test.StrPtrMaxLen",
+			expected: "StrPtrMaxLen must be a maximum of 1 character in length",
+		},
+		{
+			ns:       "Test.StrPtrLen",
+			expected: "StrPtrLen must be 2 characters in length",
+		},
+		{
+			ns:       "Test.StrPtrLt",
+			expected: "StrPtrLt must be less than 1 character in length",
+		},
+		{
+			ns:       "Test.StrPtrLte",
+			expected: "StrPtrLte must be at maximum 1 character in length",
+		},
+		{
+			ns:       "Test.StrPtrGt",
+			expected: "StrPtrGt must be greater than 10 characters in length",
+		},
+		{
+			ns:       "Test.StrPtrGte",
+			expected: "StrPtrGte must be at least 10 characters in length",
+		},
 	}
 
 	for _, tt := range tests {