Merge branch 'dm-diff-note-for-line-performance' into 'master'

Improve performance of DiffDiscussion#truncated_diff_lines and DiffNote#diff_line by removing expensive diff position calculation and comparison

Closes #41406

See merge request gitlab-org/gitlab-ce!16111

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/gitlab/diff/file.rb b/lib/gitlab/diff/file.rb
index d0cfe2386ca..cd490aaa291 100644
--- a/lib/gitlab/diff/file.rb
+++ b/lib/gitlab/diff/file.rb
@@ -61,7 +61,9 @@ module Gitlab
       end
 
       def line_for_position(pos)
-        diff_lines.find { |line| position(line) == pos }
+        return nil unless pos.position_type == 'text'
+
+        diff_lines.find { |line| line.old_line == pos.old_line && line.new_line == pos.new_line }
       end
 
       def position_for_line_code(code)