diff --git a/routers/web/repo/pull.go b/routers/web/repo/pull.go
index 5c56a6f5ad..21353bae9a 100644
--- a/routers/web/repo/pull.go
+++ b/routers/web/repo/pull.go
@@ -1507,13 +1507,12 @@ func CompareAndPullRequestPost(ctx *context.Context) {
 	// instead of 500.
 
 	if err := pull_service.NewPullRequest(ctx, repo, pullIssue, labelIDs, attachments, pullRequest, assigneeIDs); err != nil {
-		if errors.Is(err, user_model.ErrBlockedByUser) {
+		switch {
+		case errors.Is(err, user_model.ErrBlockedByUser):
 			ctx.JSONError(ctx.Tr("repo.pulls.blocked_by_user"))
-			return
-		} else if repo_model.IsErrUserDoesNotHaveAccessToRepo(err) {
+		case repo_model.IsErrUserDoesNotHaveAccessToRepo(err):
 			ctx.Error(http.StatusBadRequest, "UserDoesNotHaveAccessToRepo", err.Error())
-			return
-		} else if git.IsErrPushRejected(err) {
+		case git.IsErrPushRejected(err):
 			pushrejErr := err.(*git.ErrPushRejected)
 			message := pushrejErr.Message
 			if len(message) == 0 {
@@ -1530,7 +1529,11 @@ func CompareAndPullRequestPost(ctx *context.Context) {
 				return
 			}
 			ctx.JSONError(flashError)
-			return
+		default:
+			// It's an unexpected error.
+			// If it happens, we should add another case to handle it.
+			log.Error("Unexpected error of NewPullRequest: %T %s", err, err)
+			ctx.ServerError("CompareAndPullRequest", err)
 		}
 		ctx.ServerError("NewPullRequest", err)
 		return