progress: stop getting stuck in a nested topic during a long inner step Convert, for example, has loops like this: for revision in source_repo: progress(revisions) for file in revision: progresss(file) Prior to this change, we would start showing the file-level progress when we encountered a big revision, and then we'd get stuck in showing file-progress instead of revision progress, often producing many many instantly-completing progress bars rather than the actually-helpful top-level revisions bar.