draft proposal on provenance-qualified dependencies

[Gershom B]

Thanks for these comments Simon. It is good to have a sanity-check on
these proposals before they go before a broad audience. I'll try to
take them into account and submit this properly as a proposal
(including creating the associated discussion thread) in the next few
days. If anyone else has any thoughts (bear in mind this involves
cross-cutting changes across cabal files and a bit of ghc) please send
them on.

On "Does a particular build have to use packages from one repo only?"
-- the idea is that _per package_ a provenance may be specified to a
specific repo. If no provenance is specified, then there is the
current existing "search path-like" functionality where a chain of
overlays may live over a repo. The proposal does not address that,
because it is how things work already -- although arguably, the way in
which this works may be insufficiently understood among existing cabal
users? (In fact, looking at the cabal documentation, I see that the
description of multiple remote repos doesn't specify the manner in
which they are combined, which it should).

Cheers,
Gershom

On Fri, Feb 23, 2018 at 6:26 AM, Simon Peyton Jones
<simonpj at microsoft.com> wrote:
> Gershom
>
> Looks like a great idea.
>
> Lots of questions though:
>
>
> - I think more motivation would be helpful.  E.g. "You are in change
>   of the GHC 8.6 release.  Package authors don't want to upload a new
>   version of their packages until 8.6 is out, but you still want to
>   smoke-test 8.6 against their packages.  Doing so requires some minor
>   changes (version bounds, changes in base-library APIs etc); so you
>   want to be able to make these changes in a sandbox that won't hurt
>   anyone".      Or something like that.
>
>   Maybe describe other use-cases.  It's *much* easier to evaluate
>   a proposal when I'm totally clear what it's for.
>
> - Does a particular build have to use packages from one repo only?
>   Or is there something like a "search path"?
>
> Thanks!
>
> Simon
>
> |  -----Original Message-----
> |  From: cabal-devel [mailto:cabal-devel-bounces at haskell.org] On Behalf
> |  Of Gershom B
> |  Sent: 19 February 2018 00:26
> |  To: cabal-devel <cabal-devel at haskell.org>
> |  Subject: draft proposal on provenance-qualified dependencies
> |
> |  Hey all, I mentioned (on the long SLURP thread) that I was thinking
> |  about a general proposal for provenance-qualified dependencies to
> |  reduce coupling in the haskell ecosystem. Having worked it out a bit,
> |  I think the bigger win is it also provides a way to specify
> |  dependencies on git repos, etc., which has been an oft-requested
> |  feature.
> |
> |  I don't want to submit it as an ecosystem proposal proper without
> |  further polish, and I held off on bugging a larger audience of cabal
> |  folks until the 2.2 branch was cut. So now I'm passing this along for
> |  further comment and polish before I make a real proposal:
> |  https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithu
> |  b.com%2Fgbaz%2Fghc-proposals%2Fblob%2Fpatch-1%2Fproposals%2F0000-
> |  provenance-qualified-
> |  imports.rst&data=04%7C01%7Csimonpj%40microsoft.com%7C64fd20012b9a4b24d
> |  28508d5772f6cf2%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636545967
> |  936143539%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIi
> |  LCJBTiI6Ik1haWwifQ%3D%3D%7C-
> |  1&sdata=cH0gNADmzA%2BTkmXZEDY6lLYUTx2D2KX%2B3T8KO%2FvU86s%3D&reserved=
> |  0
> |
> |  There's no urgency, but it would be good to get some feedback in the
> |  next few weeks if possible.
> |
> |  Cheers,
> |  Gershom
> |  _______________________________________________
> |  cabal-devel mailing list
> |  cabal-devel at haskell.org
> |  https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmail.h
> |  askell.org%2Fcgi-bin%2Fmailman%2Flistinfo%2Fcabal-
> |  devel&data=04%7C01%7Csimonpj%40microsoft.com%7C64fd20012b9a4b24d28508d
> |  5772f6cf2%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636545967936143
> |  539%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTi
> |  I6Ik1haWwifQ%3D%3D%7C-
> |  1&sdata=fgfMNTNt%2BwEQ5PaTKxtl0bmO7wDv9sBiMUnWSbJhcnE%3D&reserved=0