fix bug when migrate repository 500 when repo is existed (#6188) (#6197)

Author: lunny

routers/api/v1/repo/repo.go

@@ -400,6 +400,11 @@ func Migrate(ctx *context.APIContext, form auth.MigrateRepoForm) {
 		RemoteAddr:  remoteAddr,
 	})
 	if err != nil {
+		if models.IsErrRepoAlreadyExist(err) {
+			ctx.Error(409, "", "The repository with the same name already exists.")
+			return
+		}
+
 		err = util.URLSanitizedError(err, remoteAddr)
 		if repo != nil {
 			if errDelete := models.DeleteRepository(ctx.User, ctxUser.ID, repo.ID); errDelete != nil {

routers/repo/repo.go

@@ -256,6 +256,11 @@ func MigratePost(ctx *context.Context, form auth.MigrateRepoForm) {
 		return
 	}
 
+	if models.IsErrRepoAlreadyExist(err) {
+		ctx.RenderWithErr(ctx.Tr("form.repo_name_been_taken"), tplMigrate, &form)
+		return
+	}
+
 	// remoteAddr may contain credentials, so we sanitize it
 	err = util.URLSanitizedError(err, remoteAddr)