This is just to track progress on reverting this for the 1.4.0 release as it was a source of issues. The list of PRs/things to do are: - [x] Add the Python implementation back with unit tests. - [x] Backport the #2793 to the Python codebase. - [x] Wire the python code back for the marker evaluation. - [x] Wire the python code back for the `deps` generation. I will be working on this one piece at a time to have steady progress.