[darcs-users] darcs patch: (cabal build) add two missing modules to... (and 1 more)

[Petr Rockai]

Ian Lynagh <igloo at earth.li> writes:
[snip]
> I doubt that making them "other" rather than "exposed" fixes whatever
> problem Petr saw (which presumably is that building from a clean tree
> doesn't work, but building from one in which Autoconf and ThisVersion
> have already been generated does?).

Indeed. What I see with current mainline is this:

14:34:49 | morn at eri:~/dev/darcs/upstream -> runghc Setup sdist -v
darcs changes --from-tag 2.2.0 --count
darcs changes --from-tag 2.2.0
darcs changes --context
Distribution quality warnings:
'ghc-options: -O2' is rarely needed. Check that it is giving a real benefit
and not just imposing longer compile times on your users.
Creating dist/src (and its parents)
Building source dist for darcs-2.2.0...
Creating dist/src/darcs-2.2.0 (and its parents)
Setup: Error: Could not find module: ThisVersion with any suffix:
["gc","chs","hsc","x","y","ly","cpphs","hs","lhs"]

So it is now impossible to build a distribution tarball from Cabal. I suppose
one solution would be to call writeGeneratedModules in sDistHook and add
dist/build/autogen to hs-source-dir. However:

Distribution quality errors:
'hs-source-dirs: dist/build/autogen' points inside the 'dist' directory. This
is not reliable because the location of this directory is configurable by the
user (or package manager). In addition the layout of the 'dist' directory is
subject to change in future versions of Cabal.

=> no-go.

Googling around just brought this:

http://www.nabble.com/How-to-expose-cabal-generated-installation-paths--td20659232.html

but I wasn't able to figure what do actually do there. Even runghc Setup build
does not help here, since the generated modules are under dist/, so aren't
found anyway. And I also think it's a bad idea to distribute them anyway.

Some ideas:

1 Move all ThisVersion and Autoconf references to darcs.hs. But, this can't
  really be done, since our "library" functionality prolly depends on things
  defined there.

2 Scrap Autoconf.hs and ThisVersion.hs like I did with my first
  cabalisation. Use CPP macros instead. We use them anyway. Still, there's no
  easy way to get rid of Context.hs, but it's not used in the library.
  Compromise anyone?

3 Generate files under src/ instead of under dist/. Very ugly.

Unless anyone complains, I'll go ahead with 2 and post patches.

Yours,
   Petr.

-- 
Peter Rockai | me()mornfall!net | prockai()redhat!com
 http://blog.mornfall.net | http://web.mornfall.net

"In My Egotistical Opinion, most people's C programs should be
 indented six feet downward and covered with dirt."
     -- Blair P. Houghton on the subject of C program indentation