add required_without validator

baked_in.go

@@ -65,6 +65,7 @@ var (
 		"required":          hasValue,
 		"required_with":     requiredWith,
 		"required_with_all": requiredWithAll,
+		"required_without":  requiredWithout,
 		"isdefault":         isDefault,
 		"len":               hasLengthOf,
 		"min":               hasMinOf,
@@ -1393,6 +1394,47 @@ func requiredWithAll(fl FieldLevel) bool {
 	return true
 }
 
+// RequiredWithout is the validation function
+// The field under validation must be present and not empty only when any of the other specified fields are not present.
+func requiredWithout(fl FieldLevel) bool {
+
+	field := fl.Field()
+	isValidateCurrentField := false
+	params := parseOneOfParam2(fl.Param())
+	for _, param := range params {
+		isParamFieldPresent := false
+
+		paramField := fl.Parent().FieldByName(param)
+
+		switch paramField.Kind() {
+		case reflect.Slice, reflect.Map, reflect.Ptr, reflect.Interface, reflect.Chan, reflect.Func:
+			isParamFieldPresent = !paramField.IsNil()
+		default:
+			if fl.(*validate).fldIsPointer && paramField.Interface() != nil {
+				isParamFieldPresent = true
+			}
+			isParamFieldPresent = paramField.IsValid() && paramField.Interface() != reflect.Zero(field.Type()).Interface()
+		}
+		if isParamFieldPresent {
+			isValidateCurrentField = isParamFieldPresent
+		}
+	}
+
+	if !isValidateCurrentField {
+		switch field.Kind() {
+		case reflect.Slice, reflect.Map, reflect.Ptr, reflect.Interface, reflect.Chan, reflect.Func:
+			return !field.IsNil()
+		default:
+			if fl.(*validate).fldIsPointer && field.Interface() != nil {
+				return true
+			}
+			return field.IsValid() && field.Interface() != reflect.Zero(field.Type()).Interface()
+		}
+	}
+
+	return true
+}
+
 // IsGteField is the validation function for validating if the current field's value is greater than or equal to the field specified by the param's value.
 func isGteField(fl FieldLevel) bool {
 

validator_test.go

@@ -8627,7 +8627,6 @@ func TestRequiredWith(t *testing.T) {
 		Field3 string `validate:"required_with=Field1 Field2" json:"field_3"`
 	}{
 		Field1: "test_field1",
-		Field2: "test_field2",
 		Field3: "test_field3",
 	}
 
@@ -8660,3 +8659,22 @@ func TestRequiredWithAll(t *testing.T) {
 		t.Fatalf("failed Error: %s", errs)
 	}
 }
+
+func TestRequiredWithout(t *testing.T) {
+
+	test := struct {
+		Field1 string `validate:"omitempty" json:"field_1"`
+		Field2 string `validate:"omitempty" json:"field_2"`
+		Field3 string `validate:"required_without=Field1 Field2" json:"field_3"`
+	}{
+		Field3: "test_field3",
+	}
+
+	validate := New()
+
+	errs := validate.Struct(test)
+
+	if errs != nil {
+		t.Fatalf("failed Error: %s", errs)
+	}
+}