You can do PRs from branches in the same repo on GitHub just fine if you want to. Having them in a separate repo makes more sense because 1) it doesn't require the dev submitting a PR to have anything above and beyond simple read access to the target repo, and 2) there's no concern that someone might depend on WIP branches created in those private forks, so they can be deleted or rebased at will.

The reason why it's called a "pull request" is because you're requesting the owner to pull your changes in; I don't see what this has to do with the number of repos in the picture.

> You can do PRs from branches in the same repo on GitHub just fine if you want to. Having them in a separate repo makes more sense because 1) it doesn't require the dev submitting a PR to have anything above and beyond simple read access to the target repo

Right, that's my point, though - why is there no distinction between "ability to create a real, actual, complete branch on a repo" and "ability to create a 'fake' branch that only exists for the purposes of diffs for a change request"?

For contrast, the flow I was used to inside Amazon was: 1. Clone the repo locally 2. Make my changes locally 3. Run a command that creates a 'fake branch' on the main upstream repo, which is used as the reference for the change. This works even if I don't have push-permissions on the repo (in which case, I can still push my change once it gets approval by clicking a button in the UI, whereupon a service account will push "on my behalf")

Whereas for Github, the process (if you don't have push-permissions) appears to be: 1. Fork the repo to my own Github account 2. Clone that locally (equivalent of 1. above) 3. Make my changes locally (equivalent of 2. above) 4. Push my changes to my own forked repo 5. Run a command (either CLI or UI) that creates a Pull Request from my repo to the target repo

Sure, it's only two extra steps - but I don't see why that friction has to exist in the first place. It gets _much_ worse if your change is open for a while (which will happen to coincide with the case when you don't have push permissions - that is, when you're contributing to code that you don't own), because then you need to resolve rebase locally and push to your fork rather than just being able to update in the UI (Github UI doesn't support rebase-pulls, only merges).

I see your point. FWIW I personally like it because it lets me move between my desktop and my laptop almost seamlessly - just push any changes on one end, and pull them on the other. It also means that, if any (or even all) devices suddenly die on me, whatever I was working on is still safely in my private repo.

But, yes, this does mean pushing things routinely a lot, not just when it's time to make a PR.

Fair enough! I only have a single development machine, so that advantage was invisible for me - but that makes sense!

You could theoretically get the benefits of both approaches, though: have your own personal repo to which you push "in-progress" commits for durability and portability, but maintain Amazon's tooling which generates PRs with a diff between a _local_ commit and the target (by, behind the scenes, generating the ephemeral fork from which to Request a Pull), and permitting updates to that PR from local (not necessarily "pushed to an online repo") commits. That's _still_ advantageous over GitHub's model, because:

* If you don't want to have a personal repo, you don't have to

* Even if you do, the process of updating a PR is simpler and more flexible when executed purely with local Git commands rather than by manipulating a remote repo

I appreciate the perspective, thank you!

FWIW a personal “fork” is being made for you, the tooling just makes it invisible.

Fair enough! I thought I remembered it being a (likewise invisible) branch on the upstream repo, not a separate repo entirely - but I've been out for a while and might be misremembering. Regardless, as you say, it's immaterial - so long as the tooling makes that invisible, the UX is the same.