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

[Justin Lebar via llvm-dev]

> 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.

This would solve the problem of importing history.  But if we did it
this way, you'd be unable to check out versions of the complete repo
from before the merge date.  So you'd be unable to bisect back before
the merge date, for example.  I think the umbrella repo might be a
better solution than one which had that property.

I don't know if there's a way to allow checkouts of everything from
before the merge date while also making the custom branch merge to the
monolithic repository as trivial as "git merge".  I think it may
depend on git's handling of file renames, and if so...I am not too
hopeful.  :)

For at least David's branches, I think it would be really cool if we
could merge the llvm and clang branches into a single branch with
correct history.  We wouldn't be able to do that if we used git merge
to build the monorepo out of its constituent pieces.

On Thu, 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.
>
> 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.
>
> -- Sanjoy
>
>
> On Thu, Jul 21, 2016 at 10:44 AM, Jonathan Roelofs via llvm-dev
> <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
>>
>> _______________________________________________
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>
>
>
> --
> Sanjoy Das
> http://playingwithpointers.com
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