Don't fetch Mirror when it's migrating (#19588)

- When a repository is still being migrated, don't try to fetch the
Mirror from the database. Instead skip it. This allows to visit
repositories that are still being migrated and were configured to be
mirrored.
- Resolves #19585
- Regression: #19295

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

2 files changed, 22 insertions, 5 deletions

diff --git a/models/task.go b/models/task.go
index bade1a639d..0720d28610 100644
--- a/models/task.go
+++ b/models/task.go
@@ -181,6 +181,14 @@ func GetMigratingTask(repoID int64) (*Task, error) {
 	return &task, nil
 }
 
+// HasMigratingTask returns if migrating task exist for repo.
+func HasMigratingTask(repoID int64) (bool, error) {
+	return db.GetEngine(db.DefaultContext).Exist(&Task{
+		RepoID: repoID,
+		Type:   structs.TaskTypeMigrateRepo,
+	})
+}
+
 // GetMigratingTaskByID returns the migrating task by repo's id
 func GetMigratingTaskByID(id, doerID int64) (*Task, *migration.MigrateOptions, error) {
 	task := Task{
diff --git a/modules/context/repo.go b/modules/context/repo.go
index b2c9a21f8e..c5e3a69e5c 100644
--- a/modules/context/repo.go
+++ b/modules/context/repo.go
@@ -370,15 +370,24 @@ func repoAssignment(ctx *Context, repo *repo_model.Repository) {
 	ctx.Data["Permission"] = &ctx.Repo.Permission
 
 	if repo.IsMirror {
-		var err error
-		ctx.Repo.Mirror, err = repo_model.GetMirrorByRepoID(repo.ID)
+
+		// Check if there's a migrating task.
+		// If it does exist, don't fetch the Mirror from the database as it doesn't exist yet.
+		hasTask, err := models.HasMigratingTask(repo.ID)
 		if err != nil {
 			ctx.ServerError("GetMirrorByRepoID", err)
 			return
 		}
-		ctx.Data["MirrorEnablePrune"] = ctx.Repo.Mirror.EnablePrune
-		ctx.Data["MirrorInterval"] = ctx.Repo.Mirror.Interval
-		ctx.Data["Mirror"] = ctx.Repo.Mirror
+		if !hasTask {
+			ctx.Repo.Mirror, err = repo_model.GetMirrorByRepoID(repo.ID)
+			if err != nil {
+				ctx.ServerError("GetMirrorByRepoID", err)
+				return
+			}
+			ctx.Data["MirrorEnablePrune"] = ctx.Repo.Mirror.EnablePrune
+			ctx.Data["MirrorInterval"] = ctx.Repo.Mirror.Interval
+			ctx.Data["Mirror"] = ctx.Repo.Mirror
+		}
 	}
 
 	pushMirrors, err := repo_model.GetPushMirrorsByRepoID(repo.ID)