Comment by landr0id
12 hours ago
Part of the idea behind stacked PRs is to keep your commits focused and with isolated changes that are meaningful.
A stacked PR allows you to construct a sequence of PRs in a way that allows you to iterate on and merge the isolated commits, but blocks merging items higher in the stack until the foundational changes are merged.
What can stacked PRs do that a series of well-organized commits in a single branch can't?
Stacked PRs tend to encourage a series of well-organized commits, because you review each commit separately, rather than together.
What they do that the single branch cannot is things like "have a disjoint set of reviewers where some people only review some commits", and that property is exactly why it encourages more well-organized commits, because you are reviewing them individually, rather than as a massive whole.
They also encourage amending existing commits rather than throwing fixup commits onto the end of a branch, which makes the original commit better rather than splitting it into multiple that aren't semantically useful on their own.
I think the point the GP was trying to make is that the GitHub UI ought to be able to allow you to submit a branch with multiple well-organized commits and review each commit separately with its own PR. The curation of the commits that you'd do for stacked PRs could just as easily be done with commits on a single branch; some of us don't just toss random WIP and fixup commits on a branch and leave it to GitHub to squash at the end. I.e., it's the GitHub UI rather than Git that has been lacking.
(FWIW, I'm dealing with this sort of thing at work right now - working on a complex branch, rewriting history to keep it as a sequence of clean testable and reviewable commits, with a plan to split them out to individual PRs when I finish.)