jensroemer.com
forked from
tangled.org/site
engineering blog at https://blog.tangled.sh
update intro and closing
anirudh.fi
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pages/blog/pulls.md
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pages/blog/pulls.md
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draft: true
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---
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We've been having great fun building pull requests. It's a feature we sort of
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take for granted
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We figured it would be fun to write about the engineering that went into
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building this, especially because Tangled is federated and Git repos
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can live across different servers (called "knots"). If you're new here,
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[read our intro](/intro) for the full story!
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Now, on with the show!
···
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</figure>
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## quick detour: what's in a fork?
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Forks are just "clones" of another repository. They aren't your typical
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+refs/heads/main:refs/hidden/feature-1/main
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```
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Since we already have a remote connection (`origin`, by default) to the original
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repository (remember, we cloned it earlier), we can use `fetch` with this
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refspec to bring the remote `main` branch into our local hidden ref. Each pull
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request gets its own hidden ref, hence the `refs/hidden/:localRef/:remoteRef`
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format. We keep this ref updated whenever you push new commits to your feature
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branch, ensuring that comparisons -- and any potential merge conflicts -- are always
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based on the latest state of the target branch.
···
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draft: true
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---
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We've spent the last few weeks building out a pull request system for Tangled,
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and today we want to lift the hood and show you how it works. What makes our
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implementation particularly interesting is that Tangled is federated --
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repositories can exist across different servers (which we call "knots"). This
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distributed nature creates unique engineering challenges that we had to solve.
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If you're new to Tangled and wondering what this knot business is all about,
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[read our intro](/intro) for the full story!
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Now, on with the show!
···
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</figure>
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## quick detour: what's in a fork?
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Forks are just "clones" of another repository. They aren't your typical
···
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+refs/heads/main:refs/hidden/feature-1/main
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```
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Since we already have a remote (`origin`, by default) to the original repository
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(remember, we cloned it earlier), we can use `fetch` with this refspec to bring
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the remote `main` branch into our local hidden ref. Each pull request gets its
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+
own hidden ref, hence the `refs/hidden/:localRef/:remoteRef` format. We keep
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+
this ref updated whenever you push new commits to your feature branch, ensuring
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+
that comparisons -- and any potential merge conflicts -- are always based on the
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+
latest state of the target branch.
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And just like earlier, we produce the patch by diffing your feature branch with
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the hidden tracking ref and do the whole atproto record thing.
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## future plans
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To close off this post, we wanted to share some of our future plans for pull requests:
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* `format-patch` support: both for pasting in the UI and internally. This allows
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us to show commits in the PR page, and offer different merge strategies to
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choose from (squash, rebase, ...).
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* Gerrit-style `refs/for/main`: we're still hashing out the details but being
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able to push commits to a ref to "auto-create" a PR would be super handy!
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* Change ID support: This will allow us to group changes together and track them
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across multiple commits, and to provide "history" for each change.