Undercover is slow comparing binary files

[Thong Kuah]

Normally:

$ bundle exec undercover -c "$(git merge-base origin/master HEAD)"
🚨 WARNING: Coverage data is older than your latest changes and results might be incomplete. Re-run tests to update
undercover: ✅ No coverage is missing in latest changes
Undercover finished in 20.747s

With a binary file in the staging area:

$ git s
On branch test-merge-base
Your branch is up to date with 'origin/test-merge-base'.

Untracked files:
  (use "git add <file>..." to include in what will be committed)
	git-cheat.pdf

nothing added to commit but untracked files present (use "git add" to track)
$ git add git-cheat.pdf 
$ ls -lah git-cheat.pdf 
-rw-r--r--@ 1 tkuah  staff   7.0M 23 Jun 11:59 git-cheat.pdf
$ bundle exec undercover -c "$(git merge-base origin/master HEAD)"
🚨 WARNING: Coverage data is older than your latest changes and results might be incomplete. Re-run tests to update
undercover: ✅ No coverage is missing in latest changes
Undercover finished in 119.039s

Do you think it might be OK to add an option to exclude binary files ?

[Jan Grodowski]

Thanks for reporting! It could make sense to only have an allow-list for common ruby extensions for the diff 🤔 My guess is that the slowness comes from Undercover::Changeset#full_diff and it might be where that filtering is needed.

[Thong Kuah]

Thanks for the reply @grodowski - Yes, I agree the slowness will be from full_diff possibly.

However, it looks like the file I was comparing is not a a binary, even though it's a PDF (it's some ASCII based format). So my original suggestion to exclude binary files is invalid. I'm happy to close this for now.