# LLVM monorepo transition happening on Thursday, the 17th of October **URL:** \ **Category:** Announcements\ **Created:** [October 9, 2019, 8:57pm UTC](https://forums.swift.org/t/llvm-monorepo-transition-happening-on-thursday-the-17th-of-october/29674 "2019-10-09T20:57:56Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![Alex\_L](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/alex_l/32/6202_2.png) [@Alex\_L](https://forums.swift.org/u/Alex_L)\ **Post date:** [October 9, 2019, 8:57pm UTC](https://forums.swift.org/t/llvm-monorepo-transition-happening-on-thursday-the-17th-of-october/29674/1 "2019-10-09T20:57:56Z")
Hi, I would like to provide an update to the monorepo transition posts ([https://forums.swift.org/t/llvm-monorepo-transition/25689](https://forums.swift.org/t/llvm-monorepo-transition/25689) and [https://forums.swift.org/t/llvm-monorepo-transition-update/27079](https://forums.swift.org/t/llvm-monorepo-transition-update/27079)) where I announced that Apple is working on the LLVM project monorepo transition for Swift, and posted links to the prototype monorepo that can be used with Swift. Duncan (@dexonsmith), Mishal (@mishal_shah) and I are working on executing the transition before the LLVM Dev Meeting that is happening in two weeks. The final llvm-project-v3 monorepo prototype, which is currently being finalized, will replace the existing [https://github.com/apple/llvm-project-v2](https://github.com/apple/llvm-project-v2) prototype. We are aiming to publish the llvm-project-v3 prototype monorepo by Friday, 11th of October. The transition itself will happen next week, between the 14th and the 18th of October. It will involve a couple of steps spread across a couple of days, however, we will have one day (still TBD) when the main transition will happen. The transition day will look something like this: - The [https://github.com/llvm/llvm-project](http://github.com/llvm/llvm-project) repo is forked to create [https://github.com/apple/llvm-project](http://github.com/apple/llvm-project). - The monorepo branches will be pushed to [https://github.com/apple/llvm-project](http://github.com/apple/llvm-project). - The [https://github.com/apple/swift-](http://github.com/apple/swift-){llvm, clang, lldb, ...} repos are configured to be “read-only”, by restricting commit access to all branches. - The [https://github.com/apple/llvm-project](http://github.com/apple/llvm-project) repository becomes the canonical repository, i.e. - It’s no longer generated from the split [https://github.com/apple/swift-{](http://github.com/apple/swift-%7Bclang)llvm, clang, lldb, ...} repos. - Upstream [https://github.com/llvm/llvm-project](http://github.com/llvm/llvm-project) commits are merged into it. - Any new downstream commits that previously went to [https://github.com/apple/swift-{llvm, clang, lldb, ...](http://github.com/apple/swift-%7Bclang,llvm)} can now be committed to the monorepo. Pull request testing is enabled for these downstream changes. - Swift-CI starts using [https://github.com/apple/llvm-project](http://github.com/apple/llvm-project) for its jobs. We are not expecting any downtime for Swift PR testing. We will ask the individual contributors to rerun the update checkout script again after the transition occurs to ensure that their Swift checkout updates itself to use the monorepo. I will update this thread when we will publish the finalized llvm-project-v3 prototype monorepo, and when we will determine what the actual transition day is. I’ll keep updating the forums throughout the transition day as well to keep everyone up-to-date on what the status is. ---
**Author:** ![Alex\_L](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/alex_l/32/6202_2.png) [@Alex\_L](https://forums.swift.org/u/Alex_L)\ **Post date:** [October 11, 2019, 11:13pm UTC](https://forums.swift.org/t/llvm-monorepo-transition-happening-on-thursday-the-17th-of-october/29674/2 "2019-10-11T23:13:38Z")
I would like to provide an additional update to this thread. Today, the following two new repositories have been created on [github.com/apple:](http://github.com/apple:) - [https://github.com/apple/llvm-project-v3](https://github.com/apple/llvm-project-v3), a regenerated WIP downstream fork of [https://github.com/llvm/llvm-project](https://github.com/llvm/llvm-project). - [https://github.com/apple/llvm-project-v3-split](https://github.com/apple/llvm-project-v3-split), which contains the metadata related to generating llvm-project-v3. The new llvm-project-v3 repository replaces the previous WIP downstream monorepo ([https://github.com/apple/llvm-project-v2](https://github.com/apple/llvm-project-v2)). The convention that's used for branches in the new repository is the same as in llvm-project-v2. If you've been using llvm-project-v2 for your work, please migrate to v3 before the end of next week. At the end of next week we'll stop updating llvm-project-v2, and will delete it the following week. ---
**Author:** ![smeenai](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/smeenai/32/7806_2.png) [@smeenai](https://forums.swift.org/u/smeenai)\ **Post date:** [October 14, 2019, 9:09pm UTC](https://forums.swift.org/t/llvm-monorepo-transition-happening-on-thursday-the-17th-of-october/29674/3 "2019-10-14T21:09:49Z")
This is super exciting :) Thanks for all the work and the updates! A couple of questions: - The apple-llvm-mt user has a space in its email address (`mt @ apple-llvm`). Is this intentional? - Will `llvm-project-v3` be renamed to `llvm-project`, or will `llvm-project` be regenerated without the merges from the split repositories? - Once we stop merging from the split repositories, we'll just be merging from [llvm.org](http://llvm.org) wholesale, correct? E.g. when we merge from `apple/master` into `swift/master-next`, it'll be merging changes across the entire monorepo, and not e.g. dropping any LLDB changes and having those be integrated separately. ---
**Author:** ![Alex\_L](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/alex_l/32/6202_2.png) [@Alex\_L](https://forums.swift.org/u/Alex_L)\ **Post date:** [October 14, 2019, 9:57pm UTC](https://forums.swift.org/t/llvm-monorepo-transition-happening-on-thursday-the-17th-of-october/29674/4 "2019-10-14T21:57:01Z")
- I don't think the `mt @ apple-llvm` addresses were intentional, but I don't think we'll be able to change them now. Are they causing problems on your end? - It won't be regenerated, but not quite renamed either. An empty [github.com/apple/llvm-project](http://github.com/apple/llvm-project) repository will be created by cloning [GitHub - llvm/llvm-project: The LLVM Project is a collection of modular and reusable compiler and toolchain technologies. Note: the repository does not accept github pull requests at this moment. Please submit your patches at http://reviews.llvm.org.](http://github.com/llvm/llvm-project). Then the [github.com/apple/llvm-project-v3](http://github.com/apple/llvm-project-v3) branches will be pushed to [github.com/apple/llvm-project](http://github.com/apple/llvm-project), so it's kind of a rename. Right now we are 99% sure that the commit hashes in llvm-project-v3 are the ones that will be used in the final llvm-project. - Correct. The merges will bring in the entire monorepo contents. The ToT auto merger edges will look like this: `llvm.org/master -> apple/master -> swift/master-next` This week will provide a tool which will show a status of the automerger to help users see the topology and the backlog. In the future we are planning to create PRs for merge conflicts on [github.com/apple/llvm-project](http://github.com/apple/llvm-project), so that they can be resolved even by contributors outside of Apple. Unfortunately I don't have a time frame when that will be enabled yet. ---
**Author:** ![smeenai](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/smeenai/32/7806_2.png) [@smeenai](https://forums.swift.org/u/smeenai)\ **Post date:** [October 14, 2019, 10:24pm UTC](https://forums.swift.org/t/llvm-monorepo-transition-happening-on-thursday-the-17th-of-october/29674/5 "2019-10-14T22:24:21Z")
- There's a few scripts that were assuming email addresses would be free of spaces, but it's easy enough to fix those up, and changing them to be resilient is a good thing regardless. (Things breaking on spaces is one of my least favorite aspects of shell scripts.) - Cool, sounds good. - Creating PRs for merge conflicts and allowing outside contributors to resolve them would be awesome! Looking forward to more updates on that whenever it's ready :) ---
**Author:** ![John\_McCall](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/john_mccall/32/1351_2.png) [@John\_McCall](https://forums.swift.org/u/John_McCall)\ **Post date:** [October 15, 2019, 2:57am UTC](https://forums.swift.org/t/llvm-monorepo-transition-happening-on-thursday-the-17th-of-october/29674/6 "2019-10-15T02:57:55Z")
I hate to say it, but the spaces thing definitely has the potential to be one of those things that breaks random tooling for years, so if regeneration is at all in the cards, it would be really nice. ---
**Author:** ![Alex\_L](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/alex_l/32/6202_2.png) [@Alex\_L](https://forums.swift.org/u/Alex_L)\ **Post date:** [October 15, 2019, 9:41pm UTC](https://forums.swift.org/t/llvm-monorepo-transition-happening-on-thursday-the-17th-of-october/29674/7 "2019-10-15T21:41:21Z")
Due to a bug in the generator we had to re-generate v3 to produce llvm-project-v4. The issue with `mt @ apple-llvm` should now be fixed in v4. I'll update this thread when llvm-project-v4 is public. ---
**Author:** ![John\_McCall](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/john_mccall/32/1351_2.png) [@John\_McCall](https://forums.swift.org/u/John_McCall)\ **Post date:** [October 15, 2019, 10:00pm UTC](https://forums.swift.org/t/llvm-monorepo-transition-happening-on-thursday-the-17th-of-october/29674/8 "2019-10-15T22:00:01Z")
That sounds great, I'm glad we had an opportunity to fix this. ---
**Author:** ![Alex\_L](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/alex_l/32/6202_2.png) [@Alex\_L](https://forums.swift.org/u/Alex_L)\ **Post date:** [October 15, 2019, 11:38pm UTC](https://forums.swift.org/t/llvm-monorepo-transition-happening-on-thursday-the-17th-of-october/29674/9 "2019-10-15T23:38:46Z")
I would like to provide two additional updates to this thread: 1. We decided to perform the transition this Thursday, the 17th of October. We expect that there will be a couple of hours where it won't be possible to commit downstream changes to swift- llvm, clang, lldb, compiler-rt, and clang-tools-extra, until [GitHub - apple/llvm-project: The LLVM Project is a collection of modular and reusable compiler and toolchain technologies. This fork is used to manage Apple’s stable releases of Clang as well as support the Swift project.](http://github.com/apple/llvm-project) is ready to receive commits. We are not expecting any downtime for Swift PR testing. 2. The following two new repositories have been created on [github.com/apple:](http://github.com/apple:) - [https://github.com/apple/llvm-project-v4](https://github.com/apple/llvm-project-v3), a regenerated WIP downstream fork of [https://github.com/llvm/llvm-project](https://github.com/llvm/llvm-project). - [https://github.com/apple/llvm-project-v4-split](https://github.com/apple/llvm-project-v3-split), which contains the metadata related to generating llvm-project-v4. The new llvm-project-v4 repository replaces the previous WIP downstream monorepo ([https://github.com/apple/llvm-project-v3](https://github.com/apple/llvm-project-v3)). The convention that's used for branches in the new repository is the same as in llvm-project-v3. If you've been using llvm-project-v3 for your work, please migrate to v4 before the end of next week. At the end of next week we'll stop updating llvm-project-v3, and will delete it the following week. ---
**Author:** ![Alex\_L](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/alex_l/32/6202_2.png) [@Alex\_L](https://forums.swift.org/u/Alex_L)\ **Post date:** [October 17, 2019, 8:06pm UTC](https://forums.swift.org/t/llvm-monorepo-transition-happening-on-thursday-the-17th-of-october/29674/10 "2019-10-17T20:06:16Z")
The transition process is starting now. @mishal_shah has disabled commit access to the legacy split repositories ([The GitHub swift-specific split llvm-project repositories are now read-only](https://forums.swift.org/t/the-github-swift-specific-split-llvm-project-repositories-are-now-read-only/29911)). We are in the process of finalizing [GitHub - apple/llvm-project: The LLVM Project is a collection of modular and reusable compiler and toolchain technologies. This fork is used to manage Apple’s stable releases of Clang as well as support the Swift project.](http://github.com/apple/llvm-project). We have published the v5 monorepo, which contains the final commit hashes that will be identical to the ones used for the final [GitHub - apple/llvm-project: The LLVM Project is a collection of modular and reusable compiler and toolchain technologies. This fork is used to manage Apple’s stable releases of Clang as well as support the Swift project.](http://github.com/apple/llvm-project) monorepo: - [https://github.com/apple/llvm-project-v5](https://github.com/apple/llvm-project-v5), a regenerated downstream fork of [https://github.com/llvm/llvm-project](https://github.com/llvm/llvm-project). - [https://github.com/apple/llvm-project-v5-split](https://github.com/apple/llvm-project-v5-split), which contains the metadata related to generating llvm-project-v5. ---
**Author:** ![Alex\_L](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/alex_l/32/6202_2.png) [@Alex\_L](https://forums.swift.org/u/Alex_L)\ **Post date:** [October 18, 2019, 2:28am UTC](https://forums.swift.org/t/llvm-monorepo-transition-happening-on-thursday-the-17th-of-october/29674/11 "2019-10-18T02:28:26Z")
I would like to provide an update to the monorepo transition work that happened today: - [GitHub - apple/llvm-project: The LLVM Project is a collection of modular and reusable compiler and toolchain technologies. This fork is used to manage Apple’s stable releases of Clang as well as support the Swift project.](https://github.com/apple/llvm-project) has been created. It is now the official llvm-project monorepo for the Swift project. - You are allowed to submit PRs to the [GitHub - apple/llvm-project: The LLVM Project is a collection of modular and reusable compiler and toolchain technologies. This fork is used to manage Apple’s stable releases of Clang as well as support the Swift project.](https://github.com/apple/llvm-project) repository. Please fork the repo when making changes to avoid creating unnecessary branches in the main repository. swift-ci PR testing for [GitHub - apple/llvm-project: The LLVM Project is a collection of modular and reusable compiler and toolchain technologies. This fork is used to manage Apple’s stable releases of Clang as well as support the Swift project.](https://github.com/apple/llvm-project) is now enabled, so you can test your PRs that target the `apple/*` or the `swift/*` branches. We have decided to delay giving commit access to [GitHub - apple/llvm-project: The LLVM Project is a collection of modular and reusable compiler and toolchain technologies. This fork is used to manage Apple’s stable releases of Clang as well as support the Swift project.](https://github.com/apple/llvm-project), as @mishal_shah and I are still verifying that PR testing infrastructure and CI is working as expected with the monorepo. The commit access will be restored tomorrow after the final CI and PR testing checks are performed. ---
**Author:** ![Alex\_L](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/alex_l/32/6202_2.png) [@Alex\_L](https://forums.swift.org/u/Alex_L)\ **Post date:** [October 19, 2019, 2:24am UTC](https://forums.swift.org/t/llvm-monorepo-transition-happening-on-thursday-the-17th-of-october/29674/12 "2019-10-19T02:24:16Z")
I would like to provide an update to the monorepo transition work that happened today: - The `swift/master` branch in [GitHub - apple/llvm-project: The LLVM Project is a collection of modular and reusable compiler and toolchain technologies. This fork is used to manage Apple’s stable releases of Clang as well as support the Swift project.](https://github.com/apple/llvm-project) is now open for commits. Changes to that branch require a passing pull request before they can be merged. The `swift/master` branch allows LLDB changes **only** , and does not accept changes in other split directories in llvm-project. This branch is downstream of `apple/stable/20190619` , and all the llvm/clang/compiler-rt/lld changes that are needed for `swift/master` should be merged into `apple/stable/20190619` . As of today you are still not allowed to merge PRs into `apple/stable/20190619` (the only exception are PRs that unblock CI or PR testing issues). We’re aiming to allow commit access to that branch by Monday. - The `apple/master` and the `swift/master-next` branches are not yet open for merges (the only exception are PRs that unblock CI or PR testing issues). We are aiming to allow commit access to these branches by Monday as well. - swift-ci now uses the new [GitHub - apple/llvm-project: The LLVM Project is a collection of modular and reusable compiler and toolchain technologies. This fork is used to manage Apple’s stable releases of Clang as well as support the Swift project.](https://github.com/apple/llvm-project) monorepo for its pull request testing! ---
**Author:** ![DaveZ](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/davez/32/478_2.png) [@DaveZ](https://forums.swift.org/u/DaveZ)\ **Post date:** [October 20, 2019, 6:07am UTC](https://forums.swift.org/t/llvm-monorepo-transition-happening-on-thursday-the-17th-of-october/29674/13 "2019-10-20T06:07:10Z")
Congrats on all of the hard work! One question: what are the `refs/am/changes/` and `refs/am/merge-candidate/` namespaces in the GitHub repository? I've never seen these before and I've had no luck finding docs online about these namespaces. (Maybe they're new GitHub namespaces? Like `refs/pull/`?) Is it intentional? If so, then what is it? Or is it an accident of force pushing a clone of a local repository? (This can easily happen.) ---
**Author:** ![Alex\_L](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/alex_l/32/6202_2.png) [@Alex\_L](https://forums.swift.org/u/Alex_L)\ **Post date:** [October 21, 2019, 5:24pm UTC](https://forums.swift.org/t/llvm-monorepo-transition-happening-on-thursday-the-17th-of-october/29674/14 "2019-10-21T17:24:10Z")
The `refs/am` namespace is used by our automerger, which propagates changes from [llvm.org](http://llvm.org). I haven't had the time to document it properly yet, but we're aiming to make it open and usable by the community, so that merge conflicts can be resolved even outside of Apple. ---
**Author:** ![Alex\_L](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/alex_l/32/6202_2.png) [@Alex\_L](https://forums.swift.org/u/Alex_L)\ **Post date:** [October 22, 2019, 2:16am UTC](https://forums.swift.org/t/llvm-monorepo-transition-happening-on-thursday-the-17th-of-october/29674/15 "2019-10-22T02:16:00Z")
We have restored commit access to the other branches in [GitHub - apple/llvm-project: The LLVM Project is a collection of modular and reusable compiler and toolchain technologies. This fork is used to manage Apple’s stable releases of Clang as well as support the Swift project.](https://github.com/apple/llvm-project). Please see this post for more details: [The GitHub swift-specific split llvm-project repositories are now read-only - #4 by Alex\_L](https://forums.swift.org/t/the-github-swift-specific-split-llvm-project-repositories-are-now-read-only/29911/4). ---
**Author:** ![smeenai](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/smeenai/32/7806_2.png) [@smeenai](https://forums.swift.org/u/smeenai)\ **Post date:** [December 12, 2019, 2:51am UTC](https://forums.swift.org/t/llvm-monorepo-transition-happening-on-thursday-the-17th-of-october/29674/16 "2019-12-12T02:51:39Z")
@Alex_L following up on this: > This week will provide a tool which will show a status of the automerger to help users see the topology and the backlog. Was this tool released? Apologizes if I just missed it.