cabal should force a rebuild when Extensions: or *-Options: change

[bos]

(Imported from Trac #339, reported by guest on 2008-08-23)

I have removed -fglasgow-exts from the line

Ghc-Options: -Wall -fglasgow-exts

of my .cabal file, but otherwise no file did change.

After that I was told to

./Setup.lhs configure

and then

./Setup.lhs build

The latter did not complain.

Then I did:

./Setup.lhs clean

and

./Setup.lhs build

This time I ended up with compile errors.

(Unfortunately I uploaded the package to Hackage before noticing this :-(

The right way to fix this might be to (configure to) remind the user to clean
the package before building (or to do that automatically).

[bos]

(Imported comment by @dcoutts on 2008-08-23)

Depends on #15.

[bos]

(Imported comment by @dcoutts on 2008-08-23)

Wed Aug 25 14:11:06 BST 2010  Dmitry Astapov <[email protected]>
- Auto-reconfiguration when .cabal is newer than setup-config
  This patch adds "ConfigFlags" to the "LocalBuildInfo" and reuses them to
  perform "configureAction" when .cabal file is changed. This has
  the same effect as re-running "configure" with the most recent used
  set of options, which should be the sensible thing to do.
  Closes #294, #477, #309 and #518.
  

Also closes this ticket.