Resolving "Validating unexported fields #417" (#1234)

## Add supporting for validation private fields
#417


@go-playground/validator-maintainers

---------

Co-authored-by: nikolay <[email protected]>

Author: nikolaianohyn

Makefile

@@ -15,4 +15,4 @@ test:
 bench:
 	$(GOCMD) test -run=NONE -bench=. -benchmem ./...
 
-.PHONY: test lint linters-install
+.PHONY: test lint linters-install

cache.go

@@ -126,7 +126,7 @@ func (v *Validate) extractStructCache(current reflect.Value, sName string) *cStr
 
 		fld = typ.Field(i)
 
-		if !fld.Anonymous && len(fld.PkgPath) > 0 {
+		if !v.privateFieldValidation && !fld.Anonymous && len(fld.PkgPath) > 0 {
 			continue
 		}
 

options.go

@@ -14,3 +14,12 @@ func WithRequiredStructEnabled() Option {
 		v.requiredStructEnabled = true
 	}
 }
+
+// WithPrivateFieldValidation activates validation for unexported fields
+//
+// It's experimental feature that partially uses unsafe package
+func WithPrivateFieldValidation() Option {
+	return func(v *Validate) {
+		v.privateFieldValidation = true
+	}
+}

validator.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"reflect"
 	"strconv"
+	"unsafe"
 )
 
 // per validate construct
@@ -156,7 +157,7 @@ func (v *validate) traverseField(ctx context.Context, parent reflect.Value, curr
 						structNs:       v.str2,
 						fieldLen:       uint8(len(cf.altName)),
 						structfieldLen: uint8(len(cf.name)),
-						value:          current.Interface(),
+						value:          getValue(current),
 						param:          ct.param,
 						kind:           kind,
 						typ:            current.Type(),
@@ -410,7 +411,7 @@ OUTER:
 								structNs:       v.str2,
 								fieldLen:       uint8(len(cf.altName)),
 								structfieldLen: uint8(len(cf.name)),
-								value:          current.Interface(),
+								value:          getValue(current),
 								param:          ct.param,
 								kind:           kind,
 								typ:            typ,
@@ -430,7 +431,7 @@ OUTER:
 								structNs:       v.str2,
 								fieldLen:       uint8(len(cf.altName)),
 								structfieldLen: uint8(len(cf.name)),
-								value:          current.Interface(),
+								value:          getValue(current),
 								param:          ct.param,
 								kind:           kind,
 								typ:            typ,
@@ -470,7 +471,7 @@ OUTER:
 						structNs:       v.str2,
 						fieldLen:       uint8(len(cf.altName)),
 						structfieldLen: uint8(len(cf.name)),
-						value:          current.Interface(),
+						value:          getValue(current),
 						param:          ct.param,
 						kind:           kind,
 						typ:            typ,
@@ -484,3 +485,26 @@ OUTER:
 	}
 
 }
+
+func getValue(val reflect.Value) interface{} {
+	if val.CanInterface() {
+		return val.Interface()
+	}
+
+	if val.CanAddr() {
+		return reflect.NewAt(val.Type(), unsafe.Pointer(val.UnsafeAddr())).Elem().Interface()
+	}
+
+	switch val.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return val.Int()
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return val.Uint()
+	case reflect.Complex64, reflect.Complex128:
+		return val.Complex()
+	case reflect.Float32, reflect.Float64:
+		return val.Float()
+	default:
+		return val.String()
+	}
+}

validator_instance.go

@@ -80,20 +80,21 @@ type internalValidationFuncWrapper struct {
 
 // Validate contains the validator settings and cache
 type Validate struct {
-	tagName               string
-	pool                  *sync.Pool
-	tagNameFunc           TagNameFunc
-	structLevelFuncs      map[reflect.Type]StructLevelFuncCtx
-	customFuncs           map[reflect.Type]CustomTypeFunc
-	aliases               map[string]string
-	validations           map[string]internalValidationFuncWrapper
-	transTagFunc          map[ut.Translator]map[string]TranslationFunc // map[<locale>]map[<tag>]TranslationFunc
-	rules                 map[reflect.Type]map[string]string
-	tagCache              *tagCache
-	structCache           *structCache
-	hasCustomFuncs        bool
-	hasTagNameFunc        bool
-	requiredStructEnabled bool
+	tagName                string
+	pool                   *sync.Pool
+	tagNameFunc            TagNameFunc
+	structLevelFuncs       map[reflect.Type]StructLevelFuncCtx
+	customFuncs            map[reflect.Type]CustomTypeFunc
+	aliases                map[string]string
+	validations            map[string]internalValidationFuncWrapper
+	transTagFunc           map[ut.Translator]map[string]TranslationFunc // map[<locale>]map[<tag>]TranslationFunc
+	rules                  map[reflect.Type]map[string]string
+	tagCache               *tagCache
+	structCache            *structCache
+	hasCustomFuncs         bool
+	hasTagNameFunc         bool
+	requiredStructEnabled  bool
+	privateFieldValidation bool
 }
 
 // New returns a new instance of 'validate' with sane defaults.

validator_test.go

@@ -13692,3 +13692,105 @@ func TestOmitNilAndRequired(t *testing.T) {
 		AssertError(t, err2, "OmitNil.Inner.Str", "OmitNil.Inner.Str", "Str", "Str", "required")
 	})
 }
+
+func TestPrivateFieldsStruct(t *testing.T) {
+	type tc struct {
+		stct     interface{}
+		errorNum int
+	}
+
+	tcs := []tc{
+		{
+			stct: &struct {
+				f1 int8  `validate:"required"`
+				f2 int16 `validate:"required"`
+				f3 int32 `validate:"required"`
+				f4 int64 `validate:"required"`
+			}{},
+			errorNum: 4,
+		},
+		{
+			stct: &struct {
+				f1 uint8  `validate:"required"`
+				f2 uint16 `validate:"required"`
+				f3 uint32 `validate:"required"`
+				f4 uint64 `validate:"required"`
+			}{},
+			errorNum: 4,
+		},
+		{
+			stct: &struct {
+				f1 complex64  `validate:"required"`
+				f2 complex128 `validate:"required"`
+			}{},
+			errorNum: 2,
+		},
+		{
+			stct: &struct {
+				f1 float32 `validate:"required"`
+				f2 float64 `validate:"required"`
+			}{},
+			errorNum: 2,
+		},
+		{
+			stct: struct {
+				f1 int8  `validate:"required"`
+				f2 int16 `validate:"required"`
+				f3 int32 `validate:"required"`
+				f4 int64 `validate:"required"`
+			}{},
+			errorNum: 4,
+		},
+		{
+			stct: struct {
+				f1 uint8  `validate:"required"`
+				f2 uint16 `validate:"required"`
+				f3 uint32 `validate:"required"`
+				f4 uint64 `validate:"required"`
+			}{},
+			errorNum: 4,
+		},
+		{
+			stct: struct {
+				f1 complex64  `validate:"required"`
+				f2 complex128 `validate:"required"`
+			}{},
+			errorNum: 2,
+		},
+		{
+			stct: struct {
+				f1 float32 `validate:"required"`
+				f2 float64 `validate:"required"`
+			}{},
+			errorNum: 2,
+		},
+		{
+			stct: struct {
+				f1 *int `validate:"required"`
+				f2 struct {
+					f3 int `validate:"required"`
+				}
+			}{},
+			errorNum: 2,
+		},
+		{
+			stct: &struct {
+				f1 *int `validate:"required"`
+				f2 struct {
+					f3 int `validate:"required"`
+				}
+			}{},
+			errorNum: 2,
+		},
+	}
+
+	validate := New(WithPrivateFieldValidation())
+
+	for _, tc := range tcs {
+		err := validate.Struct(tc.stct)
+		NotEqual(t, err, nil)
+
+		errs := err.(ValidationErrors)
+		Equal(t, len(errs), tc.errorNum)
+	}
+}