diff for file change mode has an error

Steps to reproduce

1. Run the following command:

   chmod +x testfile.txt
   git add testfile.txt
   git commit -m "change mode"
   git push
   

2. Check the diff of the file at Repositories >> <repo_name> >> testfile.txt >> Diff to previous
3. There will be an error message:

   "An error occurred while executing an external process: Unexpected end of diff output"
   

4. Checking the diff from the command line:

   git diff <latest_commit> <previous_commit> -- testfile.txt
   diff --git a/testfile.txt b/testfile.txt
   old mode 100755
   new mode 100644
   

It will have the same error from the pull request diff as well