I mean, GitHub allows you to squash merge a PR, which is what we do at work. I find it really simple to summarize everything in the PR in that squash commit that ends up on master. I only rebase/squash locally if I need to make it easier for review
Can you still easily bisect to find which change broke a certain feature? I usually recommend against squashing because it's easier to identify an error in a 10-line diff than in a 2000-line diff.
We use the same method and yes, it's been usually easy enough to bisect from squashed commits. In mobile development it even helps, as bisecting effort is dominated by rebuilding time -- less commits makes for much faster bisecting.
The problem is more the state of the rebased commits. If it is a dirty history, bisect will break for a myriad of random reasons (broken tests, incomplete features etc.). So if you don't squash, and want to run bisect, you _have_ to ensure that all commits are clean and working. Easier said that done.
> So if you don't squash, and want to run bisect, you _have_ to ensure that all commits are clean and working. Easier said that done.
It can be done if the commits are separate logical units of work rather than work in progress commits. One approach I take is to take the diff between your branch and master, make a new branch based off of master and stage parts of that diff (parts that make a logical unit of work) and make a commit out of it. You can do that with commands like git apply with the relevant diff hunks.
Then, to test whether each commit works, you can run git rebase --exec "your-test-commands" master and it will apply each commit in your branch and run the test commands. If they fail, then you can fix the issue in that commit and run git rebase --continue to move onto the next commit.
This way, you can get a logical set of commits where each of them are in a working state.
Can the PR still show all the individual commits when you come back to it? If so, are they still in the repo with some keepalive tag or are they persisted outside of the repo along with the PR-comments/metadata?
Yes, GitHub keeps the separate commits visible in the closed PRs. For what it's worth, I never ever found those useful anyway and worked just with the squashed commits. It's up to the team to make sure the squashed commits don't grow to thousands of lines in size.
