Fix zero

internal/utils/zero.go

@@ -13,7 +13,14 @@ type Zeroable interface {
 	IsZero() bool
 }
 
+var nilTime *time.Time
+
+// IsZero returns false if k is nil or has a zero value
 func IsZero(k interface{}) bool {
+	if k == nil {
+		return true
+	}
+
 	switch k.(type) {
 	case int:
 		return k.(int) == 0
@@ -43,31 +50,57 @@ func IsZero(k interface{}) bool {
 		return k.(bool) == false
 	case string:
 		return k.(string) == ""
+	case *time.Time:
+		return k.(*time.Time) == nilTime || IsTimeZero(*k.(*time.Time))
+	case time.Time:
+		return IsTimeZero(k.(time.Time))
 	case Zeroable:
-		return k.(Zeroable).IsZero()
+		return k.(Zeroable) == nil || k.(Zeroable).IsZero()
+	case reflect.Value: // for go version less than 1.13 because reflect.Value has no method IsZero
+		return IsValueZero(k.(reflect.Value))
 	}
-	return false
+
+	return IsValueZero(reflect.ValueOf(k))
 }
 
+var zeroType = reflect.TypeOf((*Zeroable)(nil)).Elem()
+
 func IsValueZero(v reflect.Value) bool {
-	if IsZero(v) {
-		return true
-	}
-	if IsZero(v.Interface()) {
-		return true
-	}
 	switch v.Kind() {
-	case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice:
+	case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Slice:
 		return v.IsNil()
+	case reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int, reflect.Int64:
+		return v.Int() == 0
+	case reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint, reflect.Uint64:
+		return v.Uint() == 0
+	case reflect.String:
+		return v.Len() == 0
+	case reflect.Ptr:
+		if v.IsNil() {
+			return true
+		}
+		return IsValueZero(v.Elem())
+	case reflect.Struct:
+		return IsStructZero(v)
+	case reflect.Array:
+		return IsArrayZero(v)
 	}
 	return false
 }
 
 func IsStructZero(v reflect.Value) bool {
-	if !v.IsValid() {
+	if !v.IsValid() || v.NumField() == 0 {
 		return true
 	}
 
+	if v.Type().Implements(zeroType) {
+		f := v.MethodByName("IsZero")
+		if f.IsValid() {
+			res := f.Call(nil)
+			return len(res) == 1 && res[0].Bool()
+		}
+	}
+
 	for i := 0; i < v.NumField(); i++ {
 		field := v.Field(i)
 		switch field.Kind() {

internal/utils/zero_test.go

@@ -0,0 +1,73 @@
+// Copyright 2020 The Xorm Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package utils
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type MyInt int
+type ZeroStruct struct{}
+
+func TestZero(t *testing.T) {
+	var zeroValues = []interface{}{
+		int8(0),
+		int16(0),
+		int(0),
+		int32(0),
+		int64(0),
+		uint8(0),
+		uint16(0),
+		uint(0),
+		uint32(0),
+		uint64(0),
+		MyInt(0),
+		reflect.ValueOf(0),
+		nil,
+		time.Time{},
+		&time.Time{},
+		nilTime,
+		ZeroStruct{},
+		&ZeroStruct{},
+	}
+
+	for _, v := range zeroValues {
+		t.Run(fmt.Sprintf("%#v", v), func(t *testing.T) {
+			assert.True(t, IsZero(v))
+		})
+	}
+}
+
+func TestIsValueZero(t *testing.T) {
+	var zeroReflectValues = []reflect.Value{
+		reflect.ValueOf(int8(0)),
+		reflect.ValueOf(int16(0)),
+		reflect.ValueOf(int(0)),
+		reflect.ValueOf(int32(0)),
+		reflect.ValueOf(int64(0)),
+		reflect.ValueOf(uint8(0)),
+		reflect.ValueOf(uint16(0)),
+		reflect.ValueOf(uint(0)),
+		reflect.ValueOf(uint32(0)),
+		reflect.ValueOf(uint64(0)),
+		reflect.ValueOf(MyInt(0)),
+		reflect.ValueOf(time.Time{}),
+		reflect.ValueOf(&time.Time{}),
+		reflect.ValueOf(nilTime),
+		reflect.ValueOf(ZeroStruct{}),
+		reflect.ValueOf(&ZeroStruct{}),
+	}
+
+	for _, v := range zeroReflectValues {
+		t.Run(fmt.Sprintf("%#v", v), func(t *testing.T) {
+			assert.True(t, IsValueZero(v))
+		})
+	}
+}