diff --git a/routers/web/repo/compare.go b/routers/web/repo/compare.go
index 43b2715fd..d66dd582a 100644
--- a/routers/web/repo/compare.go
+++ b/routers/web/repo/compare.go
@@ -252,7 +252,6 @@ func ParseCompareInfo(ctx *context.Context) *CompareInfo {
 		isSameRepo = true
 		ci.HeadUser = ctx.Repo.Owner
 		ci.HeadBranch = headInfos[0]
-
 	} else if len(headInfos) == 2 {
 		headInfosSplit := strings.Split(headInfos[0], "/")
 		if len(headInfosSplit) == 1 {
@@ -407,6 +406,9 @@ func ParseCompareInfo(ctx *context.Context) *CompareInfo {
 			return nil
 		}
 		defer ci.HeadGitRepo.Close()
+	} else {
+		ctx.NotFound("ParseCompareInfo", nil)
+		return nil
 	}
 
 	ctx.Data["HeadRepo"] = ci.HeadRepo