[Haskell-cafe] broken on build encoding

[Daniel Fischer]

On Monday 04 April 2011 16:19:46, Gang Yu wrote:
> Hi, cafe,
> 
>    I always get the following build failure when I try to install
> encoding:
> 
>  Configuring encoding-0.6.4...
> Warning: This package indirectly depends on multiple versions of the
> same package. This is highly likely to cause a compile failure.
> package haskell98-1.0.1.1 requires random-1.0.0.2
> package HaXml-1.20.2 requires random-1.0.0.2
> package random-1.0.0.2 requires time-1.1.4
> package random-1.0.0.2 requires time-1.2.0.4

That looks as though you have two random-1.0.0.2 packages (and two time 
packages), probably one in the global package-db and one in the user-db.
haskell98 depends on the one in the global db and probably HaXml depends on 
the one in the user-db.

For some package you installed (or did you perchance run cabal upgrade?), 
cabal seems to have reinstalled random and time (possibly more), that's not 
good.

Ask ghc-pkg about broken packages,
$ ghc-pkg check

You might need to remove packages from the user-db

> [ 6 of 65] Compiling Data.Encoding.ByteSource (
> Data/Encoding/ByteSource.hs, dist/build/Data/Encoding/ByteSource.o )
> 
> Data/Encoding/ByteSource.hs:151:17:
>     Not in scope: data constructor `State'

You have mtl-2.*, but encoding would need mtl-1.* it seems, but it hasn't 
put an upper bound on that dependency. Notify author/maintainer.

> 
> I manually installed a ghc-6.12.3, a ubuntu ghc-6.12.1, all the same?
> 
> anybody can provide helps? thanks

To circumvent the build failure, have an mtl-1.*, but no mtl-2.* available, 
then it should build (or you could edit the source to replace all 
occurrences of the data constructor State with the function state to make 
it build with mtl-2.*).