[Haskell-cafe] Problems with installing the correct version of "process". Help?

Daniel Fischer daniel.is.fischer at googlemail.com
Tue Nov 15 23:04:51 CET 2011

On Tuesday 15 November 2011, 22:34:17, Blaine wrote:
> Great question. How does one ignore the warning?


process and directory are boot packages, required by ghc  and indirectly by 
many of the packages you install(ed).
Having multiple versions of these spells trouble and breakage.
Read http://www.vex.net/~trebla/haskell/sicp.xhtml for more.

You already have two versions of directory, the one ghc was built with and It's not unlikely that you already have some unusable packages due 
to that.

$ ghc-pkg check

should tell you about such.
You should unregister the duplicate directory (, *keep the one ghc 
was built with*) and all packages depending on it.
Then you can try to reinstall those packages, before cabal installing 
anything, you should check with --dry-run whether it would install a new 
version of any of the boot packages (basically everything coming with ghc 
itself, but having a newer version of Cabal is okay). If it would, stop.

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