[Haskell-cafe] Cabal robustness

[Dominick Samperi]

I have seen the dreaded "ExitFailure 1" many times when a package fails to
install (under Linux or Windows), and I wonder why something more helpful
cannot be printed? Sometimes one gets a variant of this where the message
is "this system is not compatible with this package," but the user must
study the foo.cabal file to determine what is missing.

Also, it seems that the only way to determine if a package will install under
Windows is to try and hope for the best (often getting "ExitFailure 1" if it
fails). Wouldn't it make more sense to tag packages with the OS and
other dependencies and fail with a helpful message like "Windows not
supported" if appropriate?

It appears that some packages (like lens-4.1) have version dependencies
that cannot be satisfied (at least not on my Linux and Windows boxes),
so it appears that the Hackage hosting process suffers from a variant of
the well-known "dll hell" problem.

I tried the new (Cabal 1.18.0) sandbox feature but this did not help in my case.

Any comments on these issues would be appreciated.

Thanks,
Dominick