From 1b200bdcbabf02c141802336c583250e15ebd34e Mon Sep 17 00:00:00 2001
From: Lunny Xiao <xiaolunwen@gmail.com>
Date: Tue, 8 Sep 2020 15:40:26 +0000
Subject: [PATCH] Fix bug of ToDB when update on a nil pointer (#1786)

Fix test

Fix bug

Fix bug

Add test for insert nil struct field

Fix test

Fix bug of ToDB when update on a nil pointer

Reviewed-on: https://gitea.com/xorm/xorm/pulls/1786
---
 integrations/session_update_test.go | 54 +++++++++++++++++++++++++++--
 internal/statements/update.go       |  2 +-
 internal/statements/values.go       | 25 +++++++------
 3 files changed, 67 insertions(+), 14 deletions(-)

diff --git a/integrations/session_update_test.go b/integrations/session_update_test.go
index 1bc1f32a..07c722bd 100644
--- a/integrations/session_update_test.go
+++ b/integrations/session_update_test.go
@@ -188,6 +188,9 @@ func TestForUpdate(t *testing.T) {
 
 	// lock is NOT used
 	wg.Add(1)
+
+	wg2 := &sync.WaitGroup{}
+	wg2.Add(1)
 	go func() {
 		f3 := new(ForUpdate)
 		session3.Where("id = ?", 1)
@@ -201,10 +204,10 @@ func TestForUpdate(t *testing.T) {
 			t.Errorf("read lock failed")
 		}
 		wg.Done()
+		wg2.Done()
 	}()
 
-	// wait for go rountines
-	time.Sleep(50 * time.Millisecond)
+	wg2.Wait()
 
 	f := new(ForUpdate)
 	f.Name = "updated by session1"
@@ -1350,3 +1353,50 @@ func TestUpdateMultiplePK(t *testing.T) {
 	_, err = testEngine.ID(&MySlice{test.Id, test.Name}).Update(test)
 	assert.NoError(t, err)
 }
+
+type TestFieldType1 struct {
+	cb []byte
+}
+
+func (a *TestFieldType1) FromDB(src []byte) error {
+	a.cb = src
+	return nil
+}
+
+func (a TestFieldType1) ToDB() ([]byte, error) {
+	return a.cb, nil
+}
+
+type TestTable1 struct {
+	Id         int64
+	Field1     *TestFieldType1 `xorm:"text"`
+	UpdateTime time.Time
+}
+
+func TestNilFromDB(t *testing.T) {
+	assert.NoError(t, PrepareEngine())
+	assertSync(t, new(TestTable1))
+
+	cnt, err := testEngine.Insert(&TestTable1{
+		Field1: &TestFieldType1{
+			cb: []byte("string"),
+		},
+		UpdateTime: time.Now(),
+	})
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, cnt)
+
+	cnt, err = testEngine.Update(TestTable1{
+		UpdateTime: time.Now().Add(time.Second),
+	}, TestTable1{
+		Id: 1,
+	})
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, cnt)
+
+	cnt, err = testEngine.Insert(&TestTable1{
+		UpdateTime: time.Now(),
+	})
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, cnt)
+}
diff --git a/internal/statements/update.go b/internal/statements/update.go
index b6ae118e..ff5f82b7 100644
--- a/internal/statements/update.go
+++ b/internal/statements/update.go
@@ -130,7 +130,7 @@ func (statement *Statement) BuildUpdates(tableValue reflect.Value,
 			}
 		}
 
-		if structConvert, ok := fieldValue.Interface().(convert.Conversion); ok {
+		if structConvert, ok := fieldValue.Interface().(convert.Conversion); ok && !fieldValue.IsNil() {
 			data, err := structConvert.ToDB()
 			if err != nil {
 				return nil, nil, err
diff --git a/internal/statements/values.go b/internal/statements/values.go
index a1102c54..99eaa766 100644
--- a/internal/statements/values.go
+++ b/internal/statements/values.go
@@ -36,18 +36,21 @@ func (statement *Statement) Value2Interface(col *schemas.Column, fieldValue refl
 		}
 	}
 
-	if fieldConvert, ok := fieldValue.Interface().(convert.Conversion); ok {
-		data, err := fieldConvert.ToDB()
-		if err != nil {
-			return nil, err
+	isNil := fieldValue.Kind() == reflect.Ptr && fieldValue.IsNil()
+	if !isNil {
+		if fieldConvert, ok := fieldValue.Interface().(convert.Conversion); ok {
+			data, err := fieldConvert.ToDB()
+			if err != nil {
+				return nil, err
+			}
+			if col.SQLType.IsBlob() {
+				return data, nil
+			}
+			if nil == data {
+				return nil, nil
+			}
+			return string(data), nil
 		}
-		if col.SQLType.IsBlob() {
-			return data, nil
-		}
-		if nil == data {
-			return nil, nil
-		}
-		return string(data), nil
 	}
 
 	fieldType := fieldValue.Type()