I'm afraid that I am not one of those 'terrifyingly clever' people you speak of, Magnus, but in the past I have had a world of pain trying to use a mixture of packages between cabal and pacman.

Had a very happy time using just pacman until haskell-buildwrapper disappeared recently, and I could no longer use my favourite Haskell IDE :-(
I don't want to even try installing it using cabal, becuase then I'll be back in package-dependency hell.

I have to say, I appreciate your efforts into making Haskell easy to use on Arch so very much - I don't mean to complain at all!

regards,
Dawid

On 12/05/2014 15:47, Magnus Therning wrote:

On Mon, May 12, 2014 at 3:33 PM, Nicola Squartini <tensor5@gmail.com> wrote:

On Mon, May 12, 2014 at 2:24 PM, Dawid Loubser <dawid.loubser@ibi.co.za>
wrote:

I had a similar issue with a large number of packages.
I ended up removing and re-installing my entire Haskell ecosystem, and now
things work again.

Normally this should never happen. It's because Haskell is very strict on
dependencies (despite being lazy on other things).
In this case the reason was that those packages were added to the repository
[haskell-core] with initial release number set to 1, although they had been
in [haskell-happstack] already for some time and their release number was
higher. I removed those immediately from [haskell-happstack] to avoid
duplicate work, but they must also be manually removed from local, since
pacman always keeps the highest version-release.

In order to avoid this kind of issues in the future we should either have a
policy to coordinate work between different haskell repositories, or merge
everything into a unique repository and call it simply [haskell].

Indeed.  This is entirely my fault!

I have not been keeping track of what is available in any other repos
at all.  I was even under the impression that there were no other
maintained repos at the moment.  Clearly I am completely wrong :(

I note the absence of certain packages like haskell-buildwrapper (which
EclipseFP tools needs) - and reading the wiki, it seems confusing at this
time whether the Haskell tinkerer / developer should just be using
cabal-install to install all required packages (even though I know that
cabal is not a package management system) or... what?

Personally I don't like installing things using cabal-install because in my
opinion the distro package manager should always be in charge.

The same goes for me.  Occasionally I revert to installing a package
for the local user only, but not even then do I use `cabal install` to
do that, I prefer running `./Setup.hs configure,build,install` myself.

I do mean to look into using `cabal` myself at some point, because I
keep on hearing good things about it.  So far every time I've tried it
I've run into something weird, most recently it was trying to install
an older version of a lib than was needed, and I already had the newer
version installed on my system too.  A lot of terrifyingly clever
people swear by it though, so there has to be something I'm missing
out on!

/M