diff --git a/modules/git/ref.go b/modules/git/ref.go
index f20a175e42..7f3c2d4657 100644
--- a/modules/git/ref.go
+++ b/modules/git/ref.go
@@ -84,6 +84,19 @@ func RefNameFromCommit(shortName string) RefName {
 	return RefName(shortName)
 }
 
+func RefNameFromTypeAndShortName(tp RefType, shortName string) RefName {
+	switch tp {
+	case RefTypeBranch:
+		return RefNameFromBranch(shortName)
+	case RefTypeTag:
+		return RefNameFromTag(shortName)
+	case RefTypeCommit:
+		return RefNameFromCommit(shortName)
+	default:
+		return ""
+	}
+}
+
 func (ref RefName) String() string {
 	return string(ref)
 }
diff --git a/routers/web/repo/tree.go b/routers/web/repo/tree.go
index 9d867aebd4..0a7767aacb 100644
--- a/routers/web/repo/tree.go
+++ b/routers/web/repo/tree.go
@@ -56,16 +56,12 @@ func isExcludedEntry(entry *git.TreeEntry) bool {
 
 func Tree(ctx *context.Context) {
 	treePath := ctx.PathParam("*")
-	var refFullName git.RefName
-	switch ctx.FormTrim("ref_type") {
-	case "branch":
-		refFullName = git.RefNameFromBranch(ctx.FormTrim("ref_name"))
-	case "tag":
-		refFullName = git.RefNameFromTag(ctx.FormTrim("ref_name"))
-	default:
-		refFullName = git.RefName(ctx.FormTrim("ref_name"))
-	}
 	recursive := ctx.FormBool("recursive")
+	refFullName := git.RefNameFromTypeAndShortName(git.RefType(ctx.FormTrim("ref_type")), ctx.FormTrim("ref_name"))
+	if refFullName == "" {
+		ctx.Error(http.StatusBadRequest, "RefNameFromTypeAndShortName", "ref_type or ref_name is invalid")
+		return
+	}
 
 	var results []*files_service.TreeViewNode
 	var err error