Please add --licensedir flag to cabal-install

[peti]

Currently, cabal install license files into the location given by --docdir. Many distributions, however, have a special location into which license files (and nothing else) should be placed, i.e. both SUSE and Fedora use /usr/share/licenses/PKGNAME for that purpose. It would be nice if we could have Cabal install those license files into the correct location right away, instead of having to move the files around after the fact.

[hvr]

there's a problem though: for tooling I'm working on I need to be able to locate the license files; the docdir is registered in the pkg-db; so locating the licence file is doable now by querying the pkg-db for the docdir, and working from there.

If we add a licensdir, we need to extend the IPI format to register this new location

moreover, we have additional problems with the current install-logic which I intended to address to avoid licence files overwriting or being overwritten by name-clashes (ticket pending)

[juhp]

@hvr can you explain in more detail? Eg I don't see any docdir in package .conf files?

Anyway seems to me Cabal happily breaks API for major versions, though I see what you are saying :)

[hvr]

Breaking the API isn't a big deal if all you need to do is to change your code; but in this case you'd make it impossible to adapt to the new API, as you'd remove the ability to locate those files via the pkg-db metadata

[juhp]

So we need to add licensedir to pkg-db too?

I just don't understand how docdir is getting into it?