It's basically trying to bring the stacked diff workflow pioneered by Phabricator to GitHub.
The idea is that it allows you to better handle working on top of stuff that's not merged yet, and makes it easier for reviewers to review pieces of a larger stack of work independently.
It's really useful in larger corporate environments.
I've used stacked PRs when doing things like upgrading react-native in a monorepo. It required a massive amount of changes, and would be really hard to review as a single pull request. It has to be landed all at once, it's all or nothing. But being able to review it as smaller independent PRs is helpful.
Stacking PRs is also useful even when you don't need to merge the entire stack at once.
To my knowledge, stacked diffs were first done in the Linux kernel as stacks of patches sent over email. From there they spread to Google and Facebook. (Source: I worked on Facebook's source control team from 2012-2018 and did a lot of work to enable stacked diffs there.)
Right, I was thinking from a web-based UI. The "pull request" term is from git (AFAIK), but git itself was built to accommodate the earlier concept of mailing patches around. (Source: I've been using version control since RCS/SCCS days and contributed here and there to git in its infancy. Also an early user/contributor to Gerrit.)
Possibly from github. It got popularized there at least, encouraging forking code, and is why so many people say "pull request" when they mean "merge request".
GitHub took the "pull request" terminology from Git. A kernel developer (say) would have a bunch of changes ready in their local Git server and would request a pull from Linus, hence a pull request. There's literally a command for it:
At some point, a derivative idea becomes so different from the original one that it’s a novel idea in essence. Just like SMS is ultimately a derivative of cuneiform tablets, and yet it isn’t in any meaningful sense.
I don't think mailing stacks of patches is that different? As someone who built this stuff it was pretty obvious to me that web-based patch stack management was a relatively small evolution over mailing lists. Tools like patchwork bridged the gap initially, and we were quite familiar with them.
I'm not in a large corporate environment, but that also means we're not always a well oiled machine, and sometimes i am writing faster than the reviewer can review for a period of time -- and i really need the stacking then too.
Ha, yeah, of course I know too! I should have said it different, I meant other people were talking about needing this feature for very large teams, but I find it's needed for very small teams for perhaps different reasons related to their smallness! I need to stack PR's because I need to keep writing on top of the completed PR(s) but it might be a few days until someone else can get to reviewing because there are only a few of us and we're all doing everything.
You head to the farthest branch in the chain, fetch the latest main, and run `git rebase --update-refs main` (I prefer interactive mode myself) and then force push all of the branches from start to the end.
I know what one does manually, but how does stack make decisions here when there’s a conflict? The reason we use a rebase flow is to allow for adjusting commits that are no longer valid.
Before this feature when you were doing it manually, it was a huge problem. One of the points of this feature, is it automates rebasing the whole stack.
I don't use Github but I do work at one of the companies that popularized this workflows and it is extremely not a big deal. Pull, rebase, resolve conflicts if necessary, resubmit.
The idea is that it allows you to better handle working on top of stuff that's not merged yet, and makes it easier for reviewers to review pieces of a larger stack of work independently.
It's really useful in larger corporate environments.
I've used stacked PRs when doing things like upgrading react-native in a monorepo. It required a massive amount of changes, and would be really hard to review as a single pull request. It has to be landed all at once, it's all or nothing. But being able to review it as smaller independent PRs is helpful.
Stacking PRs is also useful even when you don't need to merge the entire stack at once.