[Hackage] #326: Cabal should support Cabal-version-dependent Setup.hs

[Hackage]

#326: Cabal should support Cabal-version-dependent Setup.hs
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  Reporter:  claus          |        Owner:         
      Type:  enhancement    |       Status:  new    
  Priority:  normal         |    Milestone:         
 Component:  Cabal library  |      Version:  1.2.3.0
  Severity:  normal         |   Resolution:         
  Keywords:                 |   Difficulty:  normal 
Ghcversion:  6.8.2          |     Platform:         
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Comment (by claus):

 Replying to [comment:1 duncan]:
 > I'm not sure I understand why exact versions are needed and why testing
 lower bounds is not enough. Testing multi-component versions in CPP macro
 language is not very easy.

 In this case, there is only one component to version-test: Cabal, as
 implicitly available in `Setup.hs` code. Exact versions are needed because
 later versions of Cabal are highly likely to break the code.

 A small example package with that issue is `ghc-paths`, I think. One
 version works with ghc head's Cabal (1.5?), another version works with
 hackage's Cabal (1.4?). So there is code that could be made to work with
 both, if Cabal provided its version as a CPP macro. But just as the 1.4
 version doesn't work with 1.5, so I wouldn't bet on the 1.5 version
 working with 1.7. Hence the need for exact versions.

-- 
Ticket URL: <http://hackage.haskell.org/trac/hackage/ticket/326#comment:2>
Hackage <http://haskell.org/cabal/>
Hackage: Cabal and related projects