diff --git a/routers/web/repo/pull.go b/routers/web/repo/pull.go
index e71b7f4be2a56..237742d6737cb 100644
--- a/routers/web/repo/pull.go
+++ b/routers/web/repo/pull.go
@@ -1296,9 +1296,10 @@ func CompareAndPullRequestPost(ctx *context.Context) {
 	// instead of 500.
 
 	if err := pull_service.NewPullRequest(ctx, repo, pullIssue, labelIDs, attachments, pullRequest, assigneeIDs); err != nil {
-		if repo_model.IsErrUserDoesNotHaveAccessToRepo(err) {
+		switch {
+		case repo_model.IsErrUserDoesNotHaveAccessToRepo(err):
 			ctx.Error(http.StatusBadRequest, "UserDoesNotHaveAccessToRepo", err.Error())
-		} else if git.IsErrPushRejected(err) {
+		case git.IsErrPushRejected(err):
 			pushrejErr := err.(*git.ErrPushRejected)
 			message := pushrejErr.Message
 			if len(message) == 0 {
@@ -1315,7 +1316,7 @@ func CompareAndPullRequestPost(ctx *context.Context) {
 				return
 			}
 			ctx.JSONError(flashError)
-		} else if errors.Is(err, user_model.ErrBlockedUser) {
+		case errors.Is(err, user_model.ErrBlockedUser):
 			flashError, err := ctx.RenderToHTML(tplAlertDetails, map[string]any{
 				"Message": ctx.Tr("repo.pulls.push_rejected"),
 				"Summary": ctx.Tr("repo.pulls.new.blocked_user"),
@@ -1325,7 +1326,7 @@ func CompareAndPullRequestPost(ctx *context.Context) {
 				return
 			}
 			ctx.JSONError(flashError)
-		} else if errors.Is(err, issues_model.ErrMustCollaborator) {
+		case errors.Is(err, issues_model.ErrMustCollaborator):
 			flashError, err := ctx.RenderToHTML(tplAlertDetails, map[string]any{
 				"Message": ctx.Tr("repo.pulls.push_rejected"),
 				"Summary": ctx.Tr("repo.pulls.new.must_collaborator"),
@@ -1335,6 +1336,11 @@ func CompareAndPullRequestPost(ctx *context.Context) {
 				return
 			}
 			ctx.JSONError(flashError)
+		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)
 		}
 		return
 	}