On Wed, Aug 5, 2009 at 1:43 PM, Thomas Girod
Hi list,
I have questions about how the haskell-platform is working with Arch. I must be missing something, please correct me :
- The haskell-platform package is a bundle of libraries/tools of specific versions that works well together - Each new version of the haskell-platform updates those libraries/tools to a more recent versions
But then, when I look at the PKGBUILD of haskell-platform, why does it have all the content of the platform declared as dependencies ? And if everything is installed as dependencies, why is the haskell-platform tarball downloaded anyway ?
Take a look in the tar-ball, it doesn't actually _contain_ all the packages. Think of haskell-platform as a meta-package, its main purpose is to pull in other packages by depending on them.
depends=('gmp' 'ghc' 'haskell-cabal' 'haskell-glut=2.1.1.2' 'haskell-http=4000.0.6' 'haskell-opengl=2.2.1.1' 'haskell-cgi=3001.1.7.1' 'haskell-editline=0.2.1.0' 'haskell-fgl=5.4.2.2' 'haskell-network=2.2.1.4' 'haskell-time=1.1.2.4' 'haskell-zlib=0.5.0.0' 'cabal-install' 'alex' 'happy' 'haddock')
Right now haskell-platform fails to install because community repo contains haskell-http version 4000.0.7, while AUR contains the 4000.0.6 version, and yaourt somehow fails to pick the right version - the problem can be solved easily, but needs human intervention.
As all libraries/tools included in haskell-platform have their own independent release-cycles on Hackage, does it mean that the "Hackage -> AUR bridge" delays the releases of haskell-platform dependencies so they match the haskell-platform release cycle ?
This is a relevant question, and it needs solving. I already got bitten by this when installing the earlier version of haskell-platform, that time it was also http that caused a diamond situation. One possibility is that it'll take care of itself once: 1. GHC is distributed without the "base packages", this'll happen in 6.12 AFAIU 2. Haskell-platform (and its dependencies) moves into [community] Then I think haskell-platform should depend on a specific version of ghc ("ghc=6.12", possibly even on a minor version "ghc=6.12.1") so that it becomes more difficult to end up in the situation where GHC "forgets" about all installed packages. Haskell-platform will have dependencies on specific versions of packages, and will hence prevent its dependencies to be out of synch with itself. Yes, this means that upgrading almost anything requires a lot of building, but that seems to be the price one has to pay to package GHC at the moment (if you want more proof read the Debian policy on Haskell :-). It'd also mean that packages that are part of HP, but which receive updates out-of-synch with HP, must be available under a different name (e.g. haskell-bleeding-edge-http :-) for people who want that. (Another option is to say we don't do that, and encourage people to use cabal-install instead. Installing such bleeding-edge packages next to HP is likely to result in versioning problems anyway.)
I wonder why the haskell-platform PKGBUILD doesn't declare its content by using the "provides" parameter, and avoid conflicts with the latest versions of those libraries on AUR by also listing them in the "replaces" parameter.
I believe my comment above, after looking inside the tar-ball, makes it obvious why it is this way. /M -- Magnus Therning (OpenPGP: 0xAB4DFBA4) magnus＠therning．org Jabber: magnus＠therning．org http://therning.org/magnus identi.ca|twitter: magthe