Any way to fetch all changed files in a PR's lifetime?

[danielap-ma]

Scenario:

Say I have a PR with the following commit history:

Commit #1:
Introduce a change to file a.txt

Commit #2:
Introduce a change to file b.txt

Commit #3:
Revert the change to file b.txt

Commit #4:
Another change (not revert) to file a.txt

The output of all_changed_files will be a.txt, which makes sense, since that's the only current diff from the target branch. But is there a way to detect b.txt had changes along the way too? I know it's possible to compare two specific commit hashes, but that's not really a viable solution.

Thanks in advance!