Fix panic bug in migrator due to lack of nil check for stmt.Schema (#6932)

migrator/migrator.go

@@ -127,6 +127,11 @@ func (m Migrator) AutoMigrate(values ...interface{}) error {
 			}
 		} else {
 			if err := m.RunWithValue(value, func(stmt *gorm.Statement) error {
+
+				if stmt.Schema == nil {
+					return errors.New("failed to get schema")
+				}
+
 				columnTypes, err := queryTx.Migrator().ColumnTypes(value)
 				if err != nil {
 					return err
@@ -211,6 +216,11 @@ func (m Migrator) CreateTable(values ...interface{}) error {
 	for _, value := range m.ReorderModels(values, false) {
 		tx := m.DB.Session(&gorm.Session{})
 		if err := m.RunWithValue(value, func(stmt *gorm.Statement) (err error) {
+
+			if stmt.Schema == nil {
+				return errors.New("failed to get schema")
+			}
+
 			var (
 				createTableSQL          = "CREATE TABLE ? ("
 				values                  = []interface{}{m.CurrentTable(stmt)}
@@ -363,6 +373,9 @@ func (m Migrator) RenameTable(oldName, newName interface{}) error {
 func (m Migrator) AddColumn(value interface{}, name string) error {
 	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
 		// avoid using the same name field
+		if stmt.Schema == nil {
+			return errors.New("failed to get schema")
+		}
 		f := stmt.Schema.LookUpField(name)
 		if f == nil {
 			return fmt.Errorf("failed to look up field with name: %s", name)
@@ -382,9 +395,11 @@ func (m Migrator) AddColumn(value interface{}, name string) error {
 // DropColumn drop value's `name` column
 func (m Migrator) DropColumn(value interface{}, name string) error {
 	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
+		if stmt.Schema != nil {
 			if field := stmt.Schema.LookUpField(name); field != nil {
 				name = field.DBName
 			}
+		}
 
 		return m.DB.Exec(
 			"ALTER TABLE ? DROP COLUMN ?", m.CurrentTable(stmt), clause.Column{Name: name},
@@ -395,6 +410,7 @@ func (m Migrator) DropColumn(value interface{}, name string) error {
 // AlterColumn alter value's `field` column' type based on schema definition
 func (m Migrator) AlterColumn(value interface{}, field string) error {
 	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
+		if stmt.Schema != nil {
 			if field := stmt.Schema.LookUpField(field); field != nil {
 				fileType := m.FullDataTypeOf(field)
 				return m.DB.Exec(
@@ -403,6 +419,7 @@ func (m Migrator) AlterColumn(value interface{}, field string) error {
 				).Error
 
 			}
+		}
 		return fmt.Errorf("failed to look up field with name: %s", field)
 	})
 }
@@ -413,9 +430,11 @@ func (m Migrator) HasColumn(value interface{}, field string) bool {
 	m.RunWithValue(value, func(stmt *gorm.Statement) error {
 		currentDatabase := m.DB.Migrator().CurrentDatabase()
 		name := field
+		if stmt.Schema != nil {
 			if field := stmt.Schema.LookUpField(field); field != nil {
 				name = field.DBName
 			}
+		}
 
 		return m.DB.Raw(
 			"SELECT count(*) FROM INFORMATION_SCHEMA.columns WHERE table_schema = ? AND table_name = ? AND column_name = ?",
@@ -429,6 +448,7 @@ func (m Migrator) HasColumn(value interface{}, field string) bool {
 // RenameColumn rename value's field name from oldName to newName
 func (m Migrator) RenameColumn(value interface{}, oldName, newName string) error {
 	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
+		if stmt.Schema != nil {
 			if field := stmt.Schema.LookUpField(oldName); field != nil {
 				oldName = field.DBName
 			}
@@ -436,6 +456,7 @@ func (m Migrator) RenameColumn(value interface{}, oldName, newName string) error
 			if field := stmt.Schema.LookUpField(newName); field != nil {
 				newName = field.DBName
 			}
+		}
 
 		return m.DB.Exec(
 			"ALTER TABLE ? RENAME COLUMN ? TO ?",
@@ -794,6 +815,9 @@ type BuildIndexOptionsInterface interface {
 // CreateIndex create index `name`
 func (m Migrator) CreateIndex(value interface{}, name string) error {
 	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
+		if stmt.Schema == nil {
+			return errors.New("failed to get schema")
+		}
 		if idx := stmt.Schema.LookIndex(name); idx != nil {
 			opts := m.DB.Migrator().(BuildIndexOptionsInterface).BuildIndexOptions(idx.Fields, stmt)
 			values := []interface{}{clause.Column{Name: idx.Name}, m.CurrentTable(stmt), opts}
@@ -826,9 +850,11 @@ func (m Migrator) CreateIndex(value interface{}, name string) error {
 // DropIndex drop index `name`
 func (m Migrator) DropIndex(value interface{}, name string) error {
 	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
+		if stmt.Schema != nil {
 			if idx := stmt.Schema.LookIndex(name); idx != nil {
 				name = idx.Name
 			}
+		}
 
 		return m.DB.Exec("DROP INDEX ? ON ?", clause.Column{Name: name}, m.CurrentTable(stmt)).Error
 	})
@@ -839,9 +865,11 @@ func (m Migrator) HasIndex(value interface{}, name string) bool {
 	var count int64
 	m.RunWithValue(value, func(stmt *gorm.Statement) error {
 		currentDatabase := m.DB.Migrator().CurrentDatabase()
+		if stmt.Schema != nil {
 			if idx := stmt.Schema.LookIndex(name); idx != nil {
 				name = idx.Name
 			}
+		}
 
 		return m.DB.Raw(
 			"SELECT count(*) FROM information_schema.statistics WHERE table_schema = ? AND table_name = ? AND index_name = ?",