Merge branch 'fix-old-mr-diffs' into 'master'

Fix old MR diffs

Closes #36516

See merge request !13744

1 files changed, 10 insertions, 1 deletions

diff --git a/lib/gitlab/diff/file.rb b/lib/gitlab/diff/file.rb
index 6d7de52cb80..1dabd4ebdd0 100644
--- a/lib/gitlab/diff/file.rb
+++ b/lib/gitlab/diff/file.rb
@@ -186,7 +186,10 @@ module Gitlab
       end
 
       def content_changed?
-        old_blob && new_blob && old_blob.id != new_blob.id
+        return blobs_changed? if diff_refs
+        return false if new_file? || deleted_file? || renamed_file?
+
+        text? && diff_lines.any?
       end
 
       def different_type?
@@ -225,6 +228,10 @@ module Gitlab
 
       private
 
+      def blobs_changed?
+        old_blob && new_blob && old_blob.id != new_blob.id
+      end
+
       def simple_viewer_class
         return DiffViewer::NotDiffable unless diffable?
 
@@ -250,6 +257,8 @@ module Gitlab
           DiffViewer::Renamed
         elsif mode_changed?
           DiffViewer::ModeChanged
+        else
+          DiffViewer::NoPreview
         end
       end