debug

migrator/migrator.go

@@ -759,7 +759,8 @@ func (m Migrator) CreateConstraint(value interface{}, name string) error {
 func (m Migrator) DropConstraint(value interface{}, name string) error {
 	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
 		if !m.HasConstraint(value, name) {
-			return nil
+			constraint, _ := m.GuessConstraintInterfaceAndTable(stmt, name)
+			return errors.New(fmt.Sprintf("Can't find constraint for %q, with guessed name %q", name, constraint))
 		}
 		constraint, table := m.GuessConstraintInterfaceAndTable(stmt, name)
 		if constraint != nil {

tests/migrate_test.go

@@ -681,6 +681,10 @@ func TestMigrateConstraint(t *testing.T) {
 			DB.Migrator().CreateConstraint(&User{}, name)
 		}
 
+		if !DB.Migrator().HasConstraint(&User{}, name) {
+			t.Fatalf("failed to create constraint %v", name)
+		}
+
 		if err := DB.Migrator().DropConstraint(&User{}, name); err != nil {
 			t.Fatalf("failed to drop constraint %v, got error %v", name, err)
 		}