WARNING: package dependencies

Daan Leijen daan at cs.uu.nl
Tue May 10 06:11:04 EDT 2005

Simon Marlow wrote:

>  1. Package builders should be careful about dependencies.  Don't
>     depend on any non-hierarchical packages from an exposed package.
>     Daan - can you fix wxHaskell?
Yes, I probably can -- I guess it is time to move forward and forget
about compatability with older ghc's (< 6.2.2)

However, I don't really understand what is wrong and what to fix :-)
(should I remove -package util and qualify explicitly in the code?)

I can probably figure it out from the docs but maybe it would help
if someone could add some "simple guidelines for package writers"
documentation that would tell concretely what is good practice
(and what is bad practice).

All the best,
-- Daan.

>  2. The GHC build could start using -fignore-all-packages to insulate
>     itself from the environment (or, simpler but more hacky:
>     -ignore-package lang).  This isn't a *solution* as such, because
>     the problem affects everyone, not just us.
>  3. We could put some safeguards in place to avoid this happening
>     in the future, e.g. warnings from Cabal and/or ghc-pkg.
>  4. Cabal needs to start using -fignore-all-packages.  Isaac?
>	Simon
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