Edward Z. Yang authored 8 years ago and Edward Z. Yang committed 8 years ago

The key idea is that once we put PackageTests in its own package, we can
ensure that its Setup.hs is compiled with the same version of Cabal
library as package-tests is compiled with.  This means that LBI reading
will *always succeed* which is quite nice.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

For the moment we cannot use ghc-options at the top level in the
cabal.project since it applies to all packages not just local ones.
Until that is fixed, use a workaround of specifying it for the two
local packages of interest directly.

On recent OS X, Cabal does not work correctly because it assumes
that a permission denied error when reading permissions on
executables, resulting in errors like "Setup: /usr/bin/ar: permission denied".

The proximal fix for this is to add a constraint on unix when we build
Cabal/cabal-install to avoid building with the buggy version of unix.
But this causes other problems:

- Bumping the version of unix means that our local build of Cabal
  will depend on things from the store.  But we weren't passing
  this to GHC when compiled Setup.hs for Cabal's package-tests.
  Set CABAL_PACKAGETESTS_DB_STACK env var explicitly to point
  to the right locations.

- The new configuration of versions exposed some bugs in some
  macro expanded code in cabal-install; we qualified those
  imports to squash unused warnings.

- The cabal-install integration-tests occasionally use Cabal from
  the system GHC.  Since this will never work on OS X, we just
  skip the tests in those cases.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

This was causing serious performance regression in the solver
so I'm commenting thise one out; see #3911 for details.

[skip ci]

Always in the tests, and also for devs in the cabal.project