fix: Sync2 will remove AUTO_INCREMENT unexpectly (#2444) (#2445)

fix #2444

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Reviewed-on: https://gitea.com/xorm/xorm/pulls/2445
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: lijunshi <lijunshi2015@163.com>
Co-committed-by: lijunshi <lijunshi2015@163.com>

README.md

@@ -465,7 +465,7 @@ res, err := engine.Transaction(func(session *xorm.Session) (interface{}, error)
 
 ## Contributing
 
-If you want to pull request, please see [CONTRIBUTING](https://gitea.com/xorm/xorm/src/branch/master/CONTRIBUTING.md). And you can also go to [Xorm on discourse](https://xorm.discourse.group) to discuss.
+If you want to pull request, please see [CONTRIBUTING](CONTRIBUTING.md). And you can also go to [Xorm on discourse](https://xorm.discourse.group) to discuss.
 
 ## Credits
 

dialects/mysql.go

@@ -402,6 +402,9 @@ func (db *mysql) AddColumnSQL(tableName string, col *schemas.Column) string {
 // ModifyColumnSQL returns a SQL to modify SQL
 func (db *mysql) ModifyColumnSQL(tableName string, col *schemas.Column) string {
 	s, _ := ColumnString(db.dialect, col, false, true)
+	if col.IsAutoIncrement {
+		s += " " + db.AutoIncrStr()
+	}
 	if col.Comment != "" {
 		s += fmt.Sprintf(" COMMENT '%s'", col.Comment)
 	}

tests/schema_test.go

@@ -751,3 +751,43 @@ func getKeysFromMap(m map[string]*schemas.Index) []string {
 	}
 	return ss
 }
+
+
+type SyncTestUser struct {
+	Id         int64       `xorm:"pk autoincr 'id' comment('primary key 1')"`
+	Name       string    `xorm:"'name' notnull comment('nickname')" json:"name"`
+}
+
+func (m *SyncTestUser) TableName() string {
+	return "sync_test_user"
+}
+
+
+type SyncTestUser2 struct {
+	Id         int64       `xorm:"pk autoincr 'id' comment('primary key 2')"`
+	Name       string    `xorm:"'name' notnull comment('nickname')" json:"name"`
+}
+
+func (m *SyncTestUser2) TableName() string {
+	return "sync_test_user"
+}
+
+func TestSync2_3(t *testing.T) {
+	if testEngine.Dialect().URI().DBType == schemas.MYSQL {
+		assert.NoError(t, PrepareEngine())
+		assertSync(t, new(SyncTestUser))
+
+		assert.NoError(t, testEngine.Sync2(new(SyncTestUser2)))
+		tables, err := testEngine.DBMetas()
+		assert.NoError(t, err)
+		tableInfo, err := testEngine.TableInfo(new(SyncTestUser2))
+
+		assert.EqualValues(t, tables[0].GetColumn("id").IsAutoIncrement, tableInfo.GetColumn("id").IsAutoIncrement)
+		assert.EqualValues(t, tables[0].GetColumn("id").Name, tableInfo.GetColumn("id").Name)
+		assert.EqualValues(t, tables[0].GetColumn("id").SQLType.Name, tableInfo.GetColumn("id").SQLType.Name)
+		assert.EqualValues(t, tables[0].GetColumn("id").Nullable, tableInfo.GetColumn("id").Nullable)
+		assert.EqualValues(t, tables[0].GetColumn("id").Comment, tableInfo.GetColumn("id").Comment)
+
+	}
+	
+}