Add Close() method to gogitRepository (#8901) (#8958)

Backport #8901 - Adjusted slightly for 1.9

In investigating #7947 it has become clear that the storage component of go-git repositories needs closing.

This PR adds this Close function and adds the Close functions as necessary.

In TransferOwnership the ctx.Repo.GitRepo is closed if it is open to help prevent the risk of multiple open files.

Fixes #7947

modules/migrations/base/uploader.go

@@ -16,4 +16,5 @@ type Uploader interface {
 	CreateComments(comments ...*Comment) error
 	CreatePullRequests(prs ...*PullRequest) error
 	Rollback() error
+	Close()
 }

modules/migrations/gitea.go

@@ -107,6 +107,13 @@ func (g *GiteaLocalUploader) CreateRepo(repo *base.Repository, opts base.Migrate
 	return err
 }
 
+// Close closes this uploader
+func (g *GiteaLocalUploader) Close() {
+	if g.gitRepo != nil {
+		g.gitRepo.Close()
+	}
+}
+
 // CreateMilestones creates milestones
 func (g *GiteaLocalUploader) CreateMilestones(milestones ...*base.Milestone) error {
 	var mss = make([]*models.Milestone, 0, len(milestones))

modules/migrations/migrate.go

@@ -83,6 +83,7 @@ func migrateRepository(downloader base.Downloader, uploader base.Uploader, opts
 	if err := uploader.CreateRepo(repo, opts); err != nil {
 		return err
 	}
+	defer uploader.Close()
 
 	if opts.Milestones {
 		log.Trace("migrating milestones")