Before reading this post - note that when I say "resolving", I'm only talking about clicking the "Resolve" button for that particular comment thread. I am not talking about actually fixing the issue that the comment is describing.
The TLDR; version is that the person who started the PR comment should be the person to mark it as resolved.
Also note that I'm talking about PRs within a team - not open source projects.
The reason I'm writing this post, is that it's something I keep on seeing come up. I leave a PR comment, and the PR author makes a change to fix it, then they resolve my comment before I have a chance to review that fix/change.
What's wrong with this? It means changes can be merged into the main branch that haven't been reviewed at all. Which kindof defeats the purpose of a PR!
Take this scenario...
However, Bob misunderstood the bug fix, and didn't fix it correctly. Jane, who spotted the bug hasn't had chance to review/accept the new changes, as Bob wrongly completed the PR comment on her behalf. Unreviewed code has now made it into the main branch, which could well be CI/CDing straight to production!
If the author of the PR comment is always the person who has the responsibility of marking that comment as resolved - this gets rid of this problem, and all changes will have had by at least two people's eyes on them.