[Haskell-cafe] library conflicts and how to resolve them
andres.loeh at googlemail.com
Sun May 6 22:06:14 CEST 2012
> $ cabal install persistent
> Resolving dependencies...
> In order, the following would be installed:
> aeson-0.6.0.2 (reinstall) changes: mtl-2.1.1 -> 220.127.116.11
> persistent-0.9.0.3 (new package)
> cabal: The following packages are likely to be broken by the reinstalls:
> Use --force-reinstalls if you want to install anyway.
> Any ideas what is going on ? I believe aeson-0.6.0.2 is already installed.
> And as far as I can tell the build of aeson-0.6.0.2 doesn't require that
> specific version of mtl.
It doesn't, otherwise it couldn't already be installed. Something
persistent depends on in the selected plan depends on mtl-18.104.22.168, and
therefore implies the reinstall.
It'd be interesting to see the trace of the solver (pass -v3 to the
cabal command). You could also try what adding --constraint="mtl ==
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