llvm dev - Jul 2016 - [RFC] One or many git repositories?

On 28 July 2016 at 22:12, Chris Bieneman <beanz at apple.com>
wrote:
> It is worth pointing out the Jenkins job that runs that is a playground I
setup for myself. It is nowhere near production ready, and it will fail
frequently as I iterate messing around with it.
Sure, I think that's implied.

cheers,
--renato

Aaaand I'm (mostly) caught up. Phew.

FWIW Chris B is right: I had been put off commenting on this thread by the
length, and the number of git discussions that have come before this. He
convinced me to make the effort to put my 2 cents in though - thanks Chris.

So - for my use-case I don't have strong feelings one way or the other*
<https://www.youtube.com/watch?v=fpaQpyU_QiM>. That said, something about
the discussion so far strikes me as dissonant: If we're going to break out
some sub-projects (the test-suite for licensing reasons, the runtimes for
modularity) then it's not really a mono-repo any more. It's a multi-repo
where we've collapsed some (but not all) of the existing repos. To the
extent that we have to build tooling to support multiple-repos
(auto-mergers for test bots, command line utils for devs who want the main
repo plus tests plus ...), could we re-use that to keep the existing
modular project setup? This might be a fairly low-benefit proposition if
the tools we develop were only usable by in-tree projects, but there are
many other users of LLVM (Swift leaps to mind since I'm at Apple, but there
are many others) who might appreciate the ability to use LLVM-provided
tools to pick-and-mix LLVM projects into their repos. Otherwise, every
downstream user will have to roll some version of these tools themselves.

- Lang.

On Thu, Jul 28, 2016 at 3:19 PM, Renato Golin via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> On 28 July 2016 at 22:12, Chris Bieneman <beanz at apple.com> wrote:
> > It is worth pointing out the Jenkins job that runs that is a
playground
> I setup for myself. It is nowhere near production ready, and it will fail
> frequently as I iterate messing around with it.
>
> Sure, I think that's implied.
>
> cheers,
> --renato
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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> On Jul 28, 2016, at 6:23 PM, Lang Hames via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
> 
> Aaaand I'm (mostly) caught up. Phew.
> 
> FWIW Chris B is right: I had been put off commenting on this thread by the
length, and the number of git discussions that have come before this. He
convinced me to make the effort to put my 2 cents in though - thanks Chris.
> 
> So - for my use-case I don't have strong feelings one way or the other*
<https://www.youtube.com/watch?v=fpaQpyU_QiM>. That said, something about
the discussion so far strikes me as dissonant: If we're going to break out
some sub-projects (the test-suite for licensing reasons, the runtimes for
modularity) then it's not really a mono-repo any more. It's a multi-repo
where we've collapsed some (but not all) of the existing repos.
This a narrow view IMO: the criteria #1 Chris mentioned to include projects in
the monorepo was " must be tightly coupled to specific versions”.
It means that even with the test suite (and possibly some runtime) out of the
monorepo, all the software that is tightly coupled would be in the monorepo, and
that alone would be enough to alleviate the needs for (most of the)
tooling/infrastructure.

> To the extent that we have to build tooling to support multiple-repos
(auto-mergers for test bots, command line utils for devs who want the main repo
plus tests plus ...), could we re-use that to keep the existing modular project
setup?
I find it a fairly different scale to clone 3 repos on a bot versus having to
keep multiple repositories *in sync* (i.e. cross repository synchronization).

> This might be a fairly low-benefit proposition if the tools we develop were
only usable by in-tree projects, but there are many other users of LLVM (Swift
leaps to mind since I'm at Apple, but there are many others) who might
appreciate the ability to use LLVM-provided tools to pick-and-mix LLVM projects
into their repos. Otherwise, every downstream user will have to roll some
version of these tools themselves.
Different problems, different tools… I’m against artificially creating
“problems" for upstream developers only because the tooling to solve them
works for downstream users.

— 
Mehdi

> 
> On Thu, Jul 28, 2016 at 3:19 PM, Renato Golin via llvm-dev <llvm-dev at
lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote:
> On 28 July 2016 at 22:12, Chris Bieneman <beanz at apple.com
<mailto:beanz at apple.com>> wrote:
> > It is worth pointing out the Jenkins job that runs that is a
playground I setup for myself. It is nowhere near production ready, and it will
fail frequently as I iterate messing around with it.
> 
> Sure, I think that's implied.
> 
> cheers,
> --renato
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
<http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev>
> 
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
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