ghc fails to parse versioned GPL and LGPL license from package configuration

[int-e]

I used this shell script to reproduce the problem:

#! /bin/sh

DIR=$(mktemp -d); cd ${DIR}; trap "cd /; rm -r ${DIR}" EXIT

echo "[]" > P
ghc-pkg -f P register - > /dev/null <<EOF
name: dummy-gpl
license: GPL
EOF
ghc-pkg -f P register - > /dev/null <<EOF
name: dummy-lgpl
license: LGPL-3
EOF
ghc -package-conf P -e 'putStrLn "success"' || echo fail

which fails like this:

ghc-stage2: P:1:163: parse error on input `Nothing'
fail

It turns out that ghc-pkg uses Cabal's code to manipulate the package configuration, while ghc comes with its own parser in ParsePkgConf.y - possible reasons include: historic reasons, better error messages, better performance.

See also this recent thread:  http://www.haskell.org/pipermail/glasgow-haskell-users/2009-July/017600.html

[int-e]

Fix: Extend ghc's parser to cover versioned licenses.

[int-e]

Alternative fix: Use Cabal's Read instance for InstalledPackageInfo?_ for parsing package configurations in ghc as well. Upside: Less code. Downsides: The code is slower (I don't have hard numbers for that) and it breaks T1969 (but that's expected - the package.conf file there needs to be updated to reflect the new format)

[simonmar]

The binary package DB (#593) will fix this. I have it working, but it's in the queue to be pushed after some other changes to the package system, so I can't push it right away.

[simonmar]

Fixed

Fri Sep 11 04:49:28 PDT 2009  Simon Marlow <marlowsd@gmail.com>
  * Remove the old package.conf parser, use read instead (fixed #3410)