[GHC] #1372: Recompilation checker should consider package versions (and other factors)

[GHC]

#1372: Recompilation checker should consider package versions (and other factors)
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    Reporter:  bringert  |        Owner:  simonmar  
        Type:  bug       |       Status:  new       
    Priority:  normal    |    Milestone:  6.8 branch
   Component:  Compiler  |      Version:  6.6       
    Severity:  normal    |   Resolution:            
    Keywords:            |   Difficulty:  Unknown   
          Os:  Unknown   |     Testcase:            
Architecture:  Unknown   |  
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Comment (by simonmar):

 Replying to [comment:14 duncan]:
   Yes, currently Cabal does not notice when the .cabal file has been
 updated without
   doing configure again. So cabal-setup build is not enough, you have to
 cabal-setup
   configure && cabal-setup build. I'd like to include this feature in the
 Cabal
   dependency analysis project, ie it should automatically rebuild the
 appropriate
   things depending on what has been changed in the .cabal file.

 This would be pretty easy to do in Cabal as it stands, right?  I can
 submit a patch if you agree.

   As for Cabal doing dependency analysis for packages, it does not need to
 be as
   accurate as ghc, so long as it is conservatively inaccurate. Then it'll
 invoke ghc
   which might decide that there's nothing to do afterall.

 To be conservative and still not invoke GHC on every file, you'd have to
 check the modification times on the `.hi` files of all package
 dependencies (possibly all the `.hi` files rather than just the ones that
 are directly imported, I'm not sure).

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1372#comment:15>
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