From f1fdd782d57ddbd2a759dad2843ee619709a4609 Mon Sep 17 00:00:00 2001
From: guillep2k <18600385+guillep2k@users.noreply.github.com>
Date: Sat, 12 Oct 2019 01:55:07 -0300
Subject: [PATCH] Add check for empty set when dropping indexes during
 migration (#8471)

* Add check for empty set when dropping indexes during migration
---
 models/migrations/migrations.go | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/models/migrations/migrations.go b/models/migrations/migrations.go
index 1f5b918de8..e14437a04b 100644
--- a/models/migrations/migrations.go
+++ b/models/migrations/migrations.go
@@ -404,9 +404,11 @@ func dropTableColumns(sess *xorm.Session, tableName string, columnNames ...strin
 		}
 		for _, index := range res {
 			indexName := index["column_name"]
-			_, err := sess.Exec(fmt.Sprintf("DROP INDEX `%s` ON `%s`", indexName, tableName))
-			if err != nil {
-				return err
+			if len(indexName) > 0 {
+				_, err := sess.Exec(fmt.Sprintf("DROP INDEX `%s` ON `%s`", indexName, tableName))
+				if err != nil {
+					return err
+				}
 			}
 		}