Delete Labels & IssueLabels on Repo Delete too (#15039)

* Doctor: find IssueLabels without existing label

* on Repo Delete: delete labels & issue_labels too

* performance nits

* Add Migration: Delete orphaned IssueLabels

* Migration v174: use Sync2

* USE sess !!!

* better func name

* code format & comment

* RAW SQL

* Update models/migrations/v176.go

* next try?

1 files changed, 11 insertions, 6 deletions

diff --git a/models/repo.go b/models/repo.go
index 15d6351251..329e63cc42 100644
--- a/models/repo.go
+++ b/models/repo.go
@@ -1447,11 +1447,11 @@ func DeleteRepository(doer *User, uid, repoID int64) error {
 		releaseAttachments = append(releaseAttachments, attachments[i].RelativePath())
 	}
 
-	if _, err = sess.Exec("UPDATE `user` SET num_stars=num_stars-1 WHERE id IN (SELECT `uid` FROM `star` WHERE repo_id = ?)", repo.ID); err != nil {
+	if _, err := sess.Exec("UPDATE `user` SET num_stars=num_stars-1 WHERE id IN (SELECT `uid` FROM `star` WHERE repo_id = ?)", repo.ID); err != nil {
 		return err
 	}
 
-	if err = deleteBeans(sess,
+	if err := deleteBeans(sess,
 		&Access{RepoID: repo.ID},
 		&Action{RepoID: repo.ID},
 		&Watch{RepoID: repoID},
@@ -1475,28 +1475,33 @@ func DeleteRepository(doer *User, uid, repoID int64) error {
 		return fmt.Errorf("deleteBeans: %v", err)
 	}
 
+	// Delete Labels and related objects
+	if err := deleteLabelsByRepoID(sess, repoID); err != nil {
+		return err
+	}
+
 	// Delete Issues and related objects
 	var attachmentPaths []string
 	if attachmentPaths, err = deleteIssuesByRepoID(sess, repoID); err != nil {
 		return err
 	}
 
-	if _, err = sess.Where("repo_id = ?", repoID).Delete(new(RepoUnit)); err != nil {
+	if _, err := sess.Where("repo_id = ?", repoID).Delete(new(RepoUnit)); err != nil {
 		return err
 	}
 
 	if repo.IsFork {
-		if _, err = sess.Exec("UPDATE `repository` SET num_forks=num_forks-1 WHERE id=?", repo.ForkID); err != nil {
+		if _, err := sess.Exec("UPDATE `repository` SET num_forks=num_forks-1 WHERE id=?", repo.ForkID); err != nil {
 			return fmt.Errorf("decrease fork count: %v", err)
 		}
 	}
 
-	if _, err = sess.Exec("UPDATE `user` SET num_repos=num_repos-1 WHERE id=?", uid); err != nil {
+	if _, err := sess.Exec("UPDATE `user` SET num_repos=num_repos-1 WHERE id=?", uid); err != nil {
 		return err
 	}
 
 	if len(repo.Topics) > 0 {
-		if err = removeTopicsFromRepo(sess, repo.ID); err != nil {
+		if err := removeTopicsFromRepo(sess, repo.ID); err != nil {
 			return err
 		}
 	}