[Haskell-cafe] Re: Why cabal forces reinstallation of happstack-utils?

[Ivan Lazar Miljenovic]

Henning Thielemann <schlepptop at henning-thielemann.de> writes:
> This makes sense. It would be certainly better if cabal-install would
> alert about the found inconsistency instead of trying to fix it. Then
> there might an additional cabal-install flag, that makes cabal-install
> prefer the output of ghc-pkg over the hackage database 00-index.tar in
> case of inconsistencies.

What do you mean by "prefer the output of ghc-pkg over the hackage
database"?  If there is a broken/invalid dependency chain, then
dependencies _have_ to be rebuilt to fix it.  ghc-pkg, however, doesn't
say _how_ those packages where built or from where.

> Could the problem also be solved by changing the version of packages
> with locally modified cabal files from a.b.c.d to a.b.c.d+1 ?

No, since it will always prefer the highest version, and if its the one
that's broken then it will just complain that that package doens't exist
and will refuse to build what you want.

-- 
Ivan Lazar Miljenovic
Ivan.Miljenovic at gmail.com
IvanMiljenovic.wordpress.com