[Haskell-cafe] Cabal problem, broken packages?

[Brandon Allbery]

It looks good because you're using it the way you're supposed to
instead of blindly using --lib to install things. That creates
dependency issues like what you're having. Basically, don't use --lib
unless you know what you're doing.

Remove the environment file, and create projects with dependencies on
the libraries you want, instead of trying to preinstall them. Cabal
knows how to manage packages for you so they don't conflict.

On Thu, Sep 15, 2022 at 12:12 PM Volker Wysk <post at volker-wysk.de> wrote:
>
> Am Donnerstag, dem 15.09.2022 um 16:31 +0100 schrieb Tom Ellis:
> > On Thu, Sep 15, 2022 at 05:23:10PM +0200, Volker Wysk wrote:
> > > I've lately set up the Haskell environment on my Linux box, with no
> > > problems. Then I have installed some packages with "cabal install", again
> > > without problems. But now I'm trying to install another package and I get a
> > > dependency conflict. It doesn't seem to matter which package I try to
> > > install:
> >
> > This is quite weird, because neither directory nor ghc are
> > dependencies of rfc5051.
> >
> > As a first step, can you try the following and report back whether you
> > successfully get to a GHCi a prompt?
> >
> > $ cabal repl -z --build-depends rfc5051
>
> This results in:
>
>
> desktop ~ $ cabal repl -z --build-depends rfc5051
> Resolving dependencies...
> Build profile: -w ghc-8.8.4 -O1
> In order, the following will be built (use -v for more details):
>  - rfc5051-0.2 (lib) (requires download & build)
>  - fake-package-0 (lib) (first run)
> Downloading  rfc5051-0.2
> Downloaded   rfc5051-0.2
> Starting     rfc5051-0.2 (lib)
> Building     rfc5051-0.2 (lib)
> Installing   rfc5051-0.2 (lib)
> Completed    rfc5051-0.2 (lib)
> Configuring library for fake-package-0..
> Preprocessing library for fake-package-0..
> Warning: No exposed modules
> GHCi, version 8.8.4: https://www.haskell.org/ghc/  :? for help
> Loaded GHCi configuration from /tmp/cabal-repl.-17863/setcwd.ghci
> Prelude>
>
>
> Looks good, doesn't it..?
>
> Volker
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-- 
brandon s allbery kf8nh
allbery.b at gmail.com