[Haskell-cafe] Version constraints and cabal.config files

[Michael Snoyman]

OK, should be working now:
http://www.stackage.org/lts/build-plan?package=warp

On Thu, Mar 26, 2015 at 5:03 PM Michael Snoyman <michael at snoyman.com> wrote:

> It's trivial for me to include them all, and equally trivial for me to
> call out which ones are shipped with GHC somehow (such as an extra flag on
> that line). I'll implement this currently to dump everything out without
> any extra flag, and we can tweak it in the future.
>
> On Thu, Mar 26, 2015 at 5:01 PM Anthony Cowley <acowley at gmail.com> wrote:
>
>> This is a touch subtle. base can be left out, but other packages that
>> ship with ghc and are usually found in the global package db should be
>> included as they can be upgraded. This has knock on effects where a new
>> version of the unix package means we have to rebuild the directory package
>> with that updated dependency, for example. This is something I already
>> handle, so I'd be happy to have everything included in the provided build
>> plan. I'd need to think more about whether or not some packages can safely
>> be totally left out, but I'm on the road at the moment and not terribly
>> capable of thought.
>>
>> Anthony
>>
>>
>> On Mar 26, 2015, at 10:50 AM, Michael Snoyman <michael at snoyman.com>
>> wrote:
>>
>> And do you want the information on the core packages (e.g., base,
>> template-haskell, containers) as well, or should they be left out?
>>
>> On Thu, Mar 26, 2015 at 4:48 PM Anthony Cowley <acowley at gmail.com> wrote:
>>
>>> Yes, but a line-based format along the lines of:
>>>
>>> foo 1.2.3
>>> bar-baz 0.1.00
>>>
>>> Would be easier to parse with the usual shell tools.
>>>
>>> Anthony
>>>
>>> On Mar 26, 2015, at 9:41 AM, Michael Snoyman <michael at snoyman.com>
>>> wrote:
>>>
>>> Is the idea that you'd be able to make a query such as:
>>>
>>> GET https://www.stackage.org/lts/1.14/build-plan?package=foo&
>>> package=bar&package=baz
>>>
>>> And get a result such as:
>>>
>>> [ {"name":"foo", "version":"1.2.3"}
>>> , ...
>>> ]
>>>
>>> ?
>>>
>>> On Thu, Mar 26, 2015 at 3:00 PM Anthony Cowley <acowley at gmail.com>
>>> wrote:
>>>
>>>>
>>>>
>>>>
>>>> On Mar 26, 2015, at 3:21 AM, Michael Snoyman <michael at snoyman.com>
>>>> wrote:
>>>>
>>>>
>>>>
>>>> On Wed, Mar 25, 2015 at 7:35 PM Anthony Cowley <acowley at gmail.com>
>>>> wrote:
>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Mar 25, 2015, at 11:03 AM, Michael Snoyman <michael at snoyman.com>
>>>>> wrote:
>>>>>
>>>>>
>>>>>
>>>>> On Wed, Mar 25, 2015 at 4:58 PM Anthony Cowley <acowley at gmail.com>
>>>>> wrote:
>>>>>
>>>>>>
>>>>>>
>>>>>> On Mar 25, 2015, at 10:51 AM, Michael Snoyman <michael at snoyman.com>
>>>>>> wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Wed, Mar 25, 2015 at 4:30 PM Anthony Cowley <
>>>>>> acowley at seas.upenn.edu> wrote:
>>>>>>
>>>>>>> On Wed, Mar 25, 2015 at 10:24 AM, Michael Snoyman <
>>>>>>> michael at snoyman.com> wrote:
>>>>>>> >
>>>>>>> >
>>>>>>> > On Wed, Mar 25, 2015 at 4:17 PM Anthony Cowley <
>>>>>>> acowley at seas.upenn.edu>
>>>>>>> > wrote:
>>>>>>> >>
>>>>>>> >> The suggestion to use "cabal install --dependencies-only ..."
>>>>>>> instead
>>>>>>> >> of "cabal freeze" in that issue is really nicely presented. "cabal
>>>>>>> >> freeze" is close to the right thing, but it's just not as fully
>>>>>>> >> featured as "cabal install" (e.g. taking flags).
>>>>>>> >>
>>>>>>> >> As for Stackage, I think it would be helpful to cache the full
>>>>>>> build
>>>>>>> >> plans computed for each package in Stackage. This is most of the
>>>>>>> work
>>>>>>> >> my Nix tooling currently does, so it would be a big time saver.
>>>>>>> >>
>>>>>>> >>
>>>>>>> >
>>>>>>> > By "full build plans," do you mean the dist/setup-config file, or
>>>>>>> something
>>>>>>> > else? That file would be problematic since it's
>>>>>>> Cabal-library-version
>>>>>>> > specific IIRC. If you're looking for the full listing of deep
>>>>>>> dependencies
>>>>>>> > and versions, we can extract that from the .yaml file using the
>>>>>>> technique I
>>>>>>> > mentioned earlier.
>>>>>>> >
>>>>>>> > Michael
>>>>>>>
>>>>>>> Yes, I meant the full listing of deep dependencies.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>> I've put together a Gist with an executable that does what I
>>>>>> described:
>>>>>>
>>>>>> https://gist.github.com/snoyberg/5b244331533fcb614523
>>>>>>
>>>>>> You give it three arguments on the command line:
>>>>>>
>>>>>> * LTS version, e.g. 1.14
>>>>>> * Name of package being checked
>>>>>> * true == only include dependencies of the library and executable,
>>>>>> anything else == include test and benchmark dependencies as well
>>>>>>
>>>>>> If that's useful, I can package that up and put it on Hackage.
>>>>>>
>>>>>> Michael
>>>>>>
>>>>>>
>>>>>> This is very helpfulness, thanks! There is a bootstrapping issue,
>>>>>> though, which is, I imagine, why both Miëtek and I have been writing much
>>>>>> more bash than we'd like. But perhaps this becomes part of a
>>>>>> cabal-install-like bootstrap.sh script to get things going.
>>>>>>
>>>>>> Anthony
>>>>>>
>>>>>
>>>>> Oh, that's actually a great idea. What if we had a program that:
>>>>>
>>>>> 1. takes a set of packages that needs to be installed, and an LTS
>>>>> version
>>>>> 2. computes the dependency tree
>>>>> 3. writes out a shell script (possibly batch program?) to wget, tar
>>>>> xf, and runghc Setup.hs in the correct order to get all of those packages
>>>>> installed
>>>>>
>>>>> As you can tell from the program I just threw together, stackage-types
>>>>> supports this kind of thing pretty trivially.
>>>>>
>>>>> Michael
>>>>>
>>>>>
>>>>> Yes, that's what the Nix tooling does. The extra bits are building up
>>>>> package databases suitable for each build without copying files all over
>>>>> the place. That has the extra benefit of being able to reuse builds when
>>>>> the recipe is unchanged. It is definitely not hard, but getting the build
>>>>> plans from stackage in a portable way would be valuable.
>>>>>
>>>>> Anthony
>>>>>
>>>>
>>>> OK, I've updated the Gist so that it produces a shell script that will
>>>> install all necessary packages. It also has a nicer optparse-applicative
>>>> interface now.
>>>>
>>>> https://gist.github.com/snoyberg/5b244331533fcb614523
>>>>
>>>> One thing I didn't do here is add support for custom GHC package
>>>> databases. I assume you'll need that, but wasn't sure exactly how you're
>>>> doing that in Nix.
>>>>
>>>> If this is useful for you, I'll start a stackage-bootstrap repo, clean
>>>> up this code a bit, and we can continue improving it from there.
>>>>
>>>> Michael
>>>>
>>>>
>>>> Just having a URL from which to GET the build plan would be most
>>>> useful. As you say, the actual package building happens after DB creation,
>>>> and that requires knowing what to put in the DB.
>>>>
>>>> Anthony
>>>>
>>>
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