[Haskell-beginners] cabal install happstack

[Gary Klindt]

Thank you very much for your answers!

When I check dependency problems

>  ghc-pkg check
I get no answer.

I tried to hide the containers package which I had installed:
>  ghc-pkg hide container...

It did not help, same error message.
Then I tried
>  cabal install --constraint="deepseq>  1.1.0.0" happstack

I was able to install this way. But:
I was not able to compile the simple Hello Happstack example ...

After all, I removed everything (ghc, haskell platform and cabal packages) and reinstalled a newer version of ghc 7.0.3.

Everything is working fine, now.

On 10/24/2011 02:11 AM, Daniel Fischer wrote:

> On Monday 24 October 2011, 01:37:19, Gary Klindt wrote:
>> Hey Haskellers,
>>
>> I tried to install happstack. Unfortunately I get the following error:
>>   >  cabal install happstack
>>
>> -Resolving dependencies...
>> -cabal: cannot configure deepseq-1.1.0.0. It requires containers>=0.2
>> &&  <0.4
>> -For the dependency on containers>=0.2&&  <0.4 there are these
>> packages: -containers-0.2.0.0, containers-0.2.0.1 and
>> containers-0.3.0.0. However none of them are available.
>> -containers-0.2.0.0 was excluded because containers-0.4.1.0 was selected
>> instead
>> -containers-0.2.0.1 was excluded because containers-0.4.1.0 was selected
>> instead
>> -containers-0.3.0.0 was excluded because containers-0.4.1.0 was selected
>> instead
> Since ghc-6.12.* cam with containers-0.3.0.0, this means you have installed
> a newer version of containers.
> That is generally not a good idea.
> containers is one of the boot packages, ghc depends on it and thus many of
> the packages you install will depend on the version that came with ghc.
>
> Run
>
> $ ghc-pkg check
>
> to see whether you already have some broken packages.
>
>> I wanted to deselect containers:
>>   >  ghc-pkg unregister containers-0.4.1.0
>>
>> -ghc-pkg: unregistering containers-0.4.1.0 would break the following
>> packages: Cabal-1.10.2.0 (use --force to override)
> Hm, a bit strange, Cabal's dependencies list only base and filepath on
> hackage, although it also depends on containers, array, directory...
> Anyway, your upgraded Cabal was built against containers-0.4.1.0, so it
> will break without that.
>
>> But I did not want to use the force option, because I like cabal, and
>> don't want to break it.
> Is it Cabal the library or cabal the executable?
> If the latter, once it's built, it doesn't need the Cabal version it was
> built with to be present.
>
>> What should I do?
> You could try
>
> a) installing happstack with a constraint on the containers version to use,
> $ cabal install --constraint="containers<  0.4" happstack
> If nothing but Cabal on your system depends on containers-0.4.1.0 yet, that
> would probably work, but that would leave your installation open to
> breakage due to conflicting containers dependencies.
>
> b) installing happstack with a later deepseq,
> $ cabal install --constraint="deepseq>  1.1.0.0"
>
> c) unregister Cabal-1.10.2.0, then containers-0.4.1.0, then reinstall
> Cabal-1.10.2 (--dry-run first, to check whether that would want to
> reinstall a new containers) [but you could also decide to use the
> Cabal-1.8.* that came with your ghc].
>
>>   >  ghc --version
>>
>> -6.12.1
>>
>> Greets
>> Gary