See #2881. We want to be using the latest commit from tj-actions/changed-files if possible.

However, we had to revert #2881 because separator was not working and there was no separator between the changed files, at least here:

We should open a bug report in https://github.com/tj-actions/changed-files to

1. reduce our tech debt to allow us to use more modern versions, and
2. be a good open-source citizen.

It'd be helpful to find a minimum reproduction: create a dedicated GitHub repository that only calls the action in GH Actions & prints the output, such as using print("""${{ steps.all-changed.outputs.all_changed_files }}""") in a Python step.

Even better is to bisect where this broke in their repository. We know that af2816c65436325c50621100d67f6e853cd1b0f1 works, but 2f7c5bfce28377bc069a65ba478de0a74aa0ca32 doesn't. So the issue must have happened somewhere between those two commits. You can use git bisect to do a binary search on their commit history to figure out where this broke. You'd clone their repository, then manually use git bisect to annotate the good and bad starting commits; try the new commits Git tells you with the minimum reproduction, and annotate if it was good or bad. (Time box this to ~20 minutes; it's still helpful to narrow the range even if we don't identify the exact commit.)