diff --git a/routers/repo/middlewares.go b/routers/repo/middlewares.go
index 757a049ab7..11b0009dbf 100644
--- a/routers/repo/middlewares.go
+++ b/routers/repo/middlewares.go
@@ -23,10 +23,16 @@ func SetEditorconfigIfExists(ctx *context.Context) {
 }
 
 func SetDiffViewStyle(ctx *context.Context) {
+	queryStyle := ctx.Query("style")
+
+	if !ctx.IsSigned {
+		ctx.Data["IsSplitStyle"] = queryStyle == "split"
+		return
+	}
+
 	var (
-		userStyle  = ctx.User.DiffViewStyle
-		queryStyle = ctx.Query("style")
-		style      string
+		userStyle = ctx.User.DiffViewStyle
+		style     string
 	)
 
 	if queryStyle == "unified" || queryStyle == "split" {