[Haskell-beginners] Why am I having such weird dependency issues?

Brandon Allbery allbery.b at gmail.com
Thu Mar 8 19:01:46 CET 2012


On Thu, Mar 8, 2012 at 12:32, Tom Murphy <amindfv at gmail.com> wrote:

> Neither of these errors makes any sense to me. What's happening?
>

At some point cabal installed a different version of a "boot library", one
required for the correct operation of ghc itself.  This tends to lead to
bizarre error messages from cabal, and even more bizarre ones if you
override cabal and try to build anyway. (Or, worse, no error messages from
that but core dumps at runtime.)


> cabal: dependencies conflict: ghc-7.0.3 requires containers ==0.4.0.0
> however
> containers-0.4.0.0 was excluded because ghc-7.0.3 requires containers
> ==0.4.2.0
>

You have multiple versions of containers installed, and yi wants to use
both of them.  Unfortunately, cabal-install loves to report the conflict
this way (I think it's bubbling the actual dependency backwards to
ghc-7.0.3 instead of leaving it where it happened?).


> cabal: cannot configure HPath-0.0.2. It requires base >=2 && <=4
> For the dependency on base >=2 && <=4 there are these packages:
> base-3.0.3.1
> and base-3.0.3.2. However none of them are available.
> base-3.0.3.1 was excluded because of the top level dependency base -any
> base-3.0.3.2 was excluded because of the top level dependency base -any
>

"base -any" here can be read as "base that came with your compiler"; it
cannot be replaced.  HPath apparently is not known to work with the version
of base that came with your ghc, so cabal tries the versions of base that
it will work with; but it can't replace the base package, and has that
rather unfortunate way of notifying you so.

I'm given to understand the unreleased version of cabal-install in the
repository does a better job of explaining these kinds of things.  As it
is, it is *very* hair-tearing....

-- 
brandon s allbery                                      allbery.b at gmail.com
wandering unix systems administrator (available)     (412) 475-9364 vm/sms
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