From 71e2b36cb855da302dc1eadf82c0fd86ff80534b Mon Sep 17 00:00:00 2001
From: sineycoder <nizhenxian@bytedance.com>
Date: Tue, 21 Jun 2022 17:05:22 +0800
Subject: [PATCH 1/2] fix: Copy to an invalid addr but can set is not
 effective.

---
 copier.go      | 17 ++++++++++++++++-
 copier_test.go | 15 +++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/copier.go b/copier.go
index 286ddb6..9fe463a 100644
--- a/copier.go
+++ b/copier.go
@@ -102,7 +102,12 @@ func copier(toValue interface{}, fromValue interface{}, opt Option) (err error)
 	)
 
 	if !to.CanAddr() {
-		return ErrInvalidCopyDestination
+		toPtr := preIndirect(reflect.ValueOf(toValue))
+		if !toPtr.CanSet() {
+			return ErrInvalidCopyDestination
+		}
+		to = reflect.New(toPtr.Type().Elem())
+		toPtr.Set(to)
 	}
 
 	// Return is from value is invalid
@@ -433,6 +438,16 @@ func deepFields(reflectType reflect.Type) []reflect.StructField {
 	return res
 }
 
+func preIndirect(reflectValue reflect.Value) reflect.Value {
+	for reflectValue.Kind() == reflect.Ptr {
+		if !reflectValue.Elem().CanAddr() {
+			break
+		}
+		reflectValue = reflectValue.Elem()
+	}
+	return reflectValue
+}
+
 func indirect(reflectValue reflect.Value) reflect.Value {
 	for reflectValue.Kind() == reflect.Ptr {
 		reflectValue = reflectValue.Elem()
diff --git a/copier_test.go b/copier_test.go
index 4cc85b4..f1fdb70 100644
--- a/copier_test.go
+++ b/copier_test.go
@@ -1666,3 +1666,18 @@ func TestSqlNullFiled(t *testing.T) {
 		t.Errorf("to (%v) value should equal from (%v) value", to.MkExpiryDateType, from.MkExpiryDateType.Int32)
 	}
 }
+
+func TestCopy(t *testing.T) {
+	now := time.Now()
+	age := int32(28)
+	src := &User{
+		Age:      14,
+		Name:     "tom",
+		Birthday: &now,
+		FakeAge:  &age,
+		Notes:    []string{"hello"},
+	}
+	var tar *User
+	err := copier.Copy(&tar, src)
+	fmt.Println(err, tar, reflect.DeepEqual(src, tar))
+}

From 7afe0ac5cf3800daff9a2425eba01d28702fdfc8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=80=AA=E6=8C=AF=E8=B4=A4?= <nizhenxian@bytedance.com>
Date: Tue, 21 Jun 2022 17:40:07 +0800
Subject: [PATCH 2/2] fix: Copy to an invalid addr but can set is not
 effective.

---
 copier.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/copier.go b/copier.go
index 9fe463a..a933d62 100644
--- a/copier.go
+++ b/copier.go
@@ -108,6 +108,10 @@ func copier(toValue interface{}, fromValue interface{}, opt Option) (err error)
 		}
 		to = reflect.New(toPtr.Type().Elem())
 		toPtr.Set(to)
+		// reindirect
+		if to = indirect(reflect.ValueOf(toValue)); !to.CanAddr() {
+			return ErrInvalidCopyDestination
+		}
 	}
 
 	// Return is from value is invalid