Check if blob or tree and redirect to the correct one.

app/controllers/projects/blob_controller.rb

@@ -30,8 +30,12 @@ class Projects::BlobController < Projects::ApplicationController
   def blob
     @blob ||= @repository.blob_at(@commit.id, @path)
 
-    return not_found! unless @blob
-
+    if @blob
       @blob
+    elsif tree.entries.any?
+      redirect_to project_tree_path(@project, File.join(@ref, @path)) and return
+    else
+      return not_found!
+    end
   end
 end

app/controllers/projects/tree_controller.rb

 # Controller for viewing a repository's file structure
 class Projects::TreeController < Projects::BaseTreeController
   def show
-    return not_found! if tree.entries.empty?
+
+    if tree.entries.empty?
+      if @repository.blob_at(@commit.id, @path)
+        redirect_to project_blob_path(@project, File.join(@ref, @path)) and return
+      else
+        return not_found!
+      end
+    end
 
     respond_to do |format|
       format.html