[llvm-dev] [RFC] One or many git repositories?

[Mehdi Amini via llvm-dev]

> On Jul 21, 2016, at 2:32 PM, Mehdi Amini via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> 
>> 
>> On Jul 21, 2016, at 2:29 PM, Mehdi Amini <mehdi.amini at apple.com> wrote:
>> 
>> 
>>> On Jul 21, 2016, at 11:03 AM, Sanjoy Das via llvm-dev <llvm-dev at lists.llvm.org> wrote:
>>> 
>>> FWIW, like David Chisnall, we (Azul) have a problem with rewriting
>>> history.  
>>> Our LLVM fork has O(100) changes diverging from upstream
>>> (though our branching structure is simple), and keeping all of that
>>> history is important.
>> 
>> Nobody downstream has to adopt the new structure, I believe it is possible to extract only the “llvm” commits from the new repo and rebase them on top of the existing llvm repo.
>> This can be done on the fly by you CI, but it is also a deterministic process, i.e. you can restart from scratch anytime (assuming you have the original llvm.git repo and the new one).

To clarify, I believe we* can maintain this read-only view of the individual repo like (https://github.com/llvm-mirror/llvm <https://github.com/llvm-mirror/llvm> and siblings) with their current history (hashes…), and adding on top the new commits from the new repo: 

*: we could be the LLVM foundation or some volunteer or each downstream user/org.

— 
Mehdi



>> 
>>> 
>>> What do people think of having one (or a set of) merge commit(s)
>>> merging in the non-llvm projects that will be part of the new
>>> monorepo?  That's the only technique I can think of that will preserve
>>> history for downstream users by construction.
>> 
>> I have no idea what you mean here?
> 
> I think I understand what you mean:
> 
> 1) checkout the existing clang repo
> 2) move everything in a subdirectory “clang”
> 3) commit the move
> 4) merge this into the new “llvm-project”.
> 5) repeat for every single project
> 
> That should preserve the hashes and avoid user to have to “extract” the subproject to merge into their own branch.
> Annoyingly, it breaks git log path/to/file though.
> 
> — 
> Mehdi
> 
> 
> 
> 
>>> 
>>> 
>>> 
>>> On Thu, Jul 21, 2016 at 10:44 AM, Jonathan Roelofs via llvm-dev
>>> <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote:
>>>> 
>>>> 
>>>> On 7/21/16 11:03 AM, C Bergström via llvm-dev wrote:
>>>>> 
>>>>> Monolithic is trying to solve the wrong problem - it's that simple.
>>>>> Any discussion or attempt to coddle those who think it's necessary is
>>>>> a waste of time. #dictator
>>>> 
>>>> 
>>>> Christopher,
>>>> 
>>>> AFAICT, you haven't explained *why* it is the wrong problem. Mind
>>>> elaborating on that?
>>>> 
>>>> 
>>>> Jon
>>>> 
>>>> p.s: edicts, appeals to authority, and ad hominems are not useful for
>>>> discussion. Doing that, and following up with "#dictator" further solidifies
>>>> that you know your own argument is b-s.... please stop.
>>>> 
>>>> --
>>>> Jon Roelofs
>>>> jonathan at codesourcery.com
>>>> CodeSourcery / Mentor Embedded
>>>> 
>>>> _______________________________________________
>>>> LLVM Developers mailing list
>>>> llvm-dev at lists.llvm.org
>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>> 
>>> 
>>> 
>>> -- 
>>> Sanjoy Das
>>> http://playingwithpointers.com
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> llvm-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>> 
> 
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