draft proposal on provenance-qualified dependencies

[Simon Peyton Jones]

|  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?

Well I can say with certainty that it's insufficiently understood by /this/ cabal user.

I had no idea there could be more than one repo, which 'cabal update' caches locally.

Simon

|  -----Original Message-----
|  From: Gershom B [mailto:gershomb at gmail.com]
|  Sent: 23 February 2018 15:02
|  To: Simon Peyton Jones <simonpj at microsoft.com>
|  Cc: cabal-devel <cabal-devel at haskell.org>
|  Subject: Re: draft proposal on provenance-qualified dependencies
|  
|  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%2Fgit
|  > | hu
|  > |  b.com%2Fgbaz%2Fghc-proposals%2Fblob%2Fpatch-1%2Fproposals%2F0000-
|  > |  provenance-qualified-
|  > |
|  > |
|  imports.rst&data=04%7C01%7Csimonpj%40microsoft.com%7C64fd20012b9a4b2
|  > | 4d
|  > |
|  > |
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|  936143539%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMz
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|  > |  LCJBTiI6Ik1haWwifQ%3D%3D%7C-
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|  1&sdata=cH0gNADmzA%2BTkmXZEDY6lLYUTx2D2KX%2B3T8KO%2FvU86s%3D&reserve
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|  > |  0
|  > |
|  > |  There's no urgency, but it would be good to get some feedback in
|  > | the  next few weeks if possible.
|  > |
|  > |  Cheers,
|  > |  Gershom
|  > |  _______________________________________________
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|  > | .h
|  > |  askell.org%2Fcgi-bin%2Fmailman%2Flistinfo%2Fcabal-
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