Date: Thu, 21 Oct 2021 13:36:15 +0200
From: Natanael Copa <ncopa@alpinelinux.org>
To: Alpine development <~alpine/devel@lists.alpinelinux.org>
Cc: Olliver Schinagl <oliver@schinagl.nl>, Mitch Tishmack
 <mitch.tishmack@gmail.com>
Subject: Remove haskell compiler (ghc) from alpine
Message-ID: <20211021133615.32f08070@ncopa-desktop.lan>
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## TL;DR

ghc is blocking the 3.15 release, so I wonder if we can remove
the following packages:

- community/gch
- community/cabal
- community/shellcheck
- testing/pandoc
- testing/apostrophe

## longer explanation

Maintaining ghc and cabal packages requries significant amount
of time and skills. To my understanding, upstream recommends use ghcup
to install haskell, not the distro package.

We use shellcheck in our CI but shellcheck is available from upstream
as a statically precompiled binary[1] which we can use for our infra.

pandoc is also available as precompiled binary[2].

But those cannot be used as dependencies for other packages which means
that we cannot provide a package for testing/apostrophe or
testing/py3-pypandoc.

Would it be ok to remove those packages to save ourselves from
significant amount of maintenance work?

Alternatively, are there anyone who have time and skills to take
maintenance for those? What needs to be done:

- complete the update of ghc to 9.0.2 [3]:
  - either revert back to system libffi (and add comment in libffi
    package that special care is needed when upgrading libffi due to
    ghc needing ghc to update) or solve how the bundled libffi is handled.
  - find out how to update cabal. one of the following alternatives
    needs to be done:
    a) copy the way boostrap.sh from cabal 3.2.0.0 works (fetch and
       build all the needed deps together with cabal-install itself).
    b) figure out if/how we can use cabal's bootstrap.py[4]
    c) find out how to use previous cabal to update cabal (another
       circular dep) and investigate what the consequences of that is.
       (any external dependencies will need special care when the are
       upgraded).
    d) create apk packages for the dependencies, similar to what arch
       linux does[5]. eg package for uusi[6], haskell-hashable[7] etc.
  - split out ghc-libs runtime libraries

- rebuild everything using the ghc (shellcheck, pandoc, py3-pypandoc
  etc)

- figure out and document how to do the haskell-* packages in case
  option d) was chosen above. Maybe also add support for haskell
  packages in newapkbuild.

- figure out how to bootstrap ghc and cabal for the remaining
  architectures. At least aarch64.

I have already spent way too many days on ghc and would prefer that
someone else takes over or that we remove it.

[1]: https://github.com/koalaman/shellcheck/releases/tag/v0.7.2
[2]: https://github.com/jgm/pandoc/releases/tag/2.14.2
[3]: https://gitlab.alpinelinux.org/alpine/aports/-/merge_requests/20134
[4]: https://github.com/haskell/cabal/tree/master/bootstrap
[5]: https://github.com/archlinux/svntogit-community/blob/packages/cabal-install/trunk/PKGBUILD
[6]: https://github.com/archlinux/svntogit-community/blob/packages/uusi/trunk/PKGBUILD
[7]: https://github.com/archlinux/svntogit-community/blob/packages/haskell-hashable/trunk/PKGBUILD