[Hackage] #951: Incorrect error messages for non-existing dependencies

[Hackage]

#951: Incorrect error messages for non-existing dependencies
---------------------------------+------------------------------------------
  Reporter:  guest               |        Owner:                
      Type:  defect              |       Status:  new           
  Priority:  normal              |    Milestone:                
 Component:  cabal-install tool  |      Version:  1.14.0        
  Severity:  normal              |     Keywords:  message solver
Difficulty:  unknown             |   Ghcversion:  7.4.1         
  Platform:  Linux               |  
---------------------------------+------------------------------------------
 When the build-depends-field contains non-existing packages, cabal-install
 sometimes does not report that these packages could not be found but
 complains about other constraints being unsolvable.

 The attached cabal-file contains a dependency for a non-existing package
 called "bogus". This is what I get:

 {{{
 $ cabal install --only-dependencies --dry-run
 Resolving dependencies...
 cabal: Could not resolve dependencies:
 next goal: foo (user goal)
 rejecting: foo-1.0 (global constraint requires ==0.1.0.0)
 trying: foo-0.1.0.0
 trying: heist-0.8.0 (dependency of foo-0.1.0.0)
 trying: transformers-0.3.0.0 (dependency of heist-0.8.0)
 next goal: mtl (dependency of heist-0.8.0)
 rejecting: mtl-2.1.1, 2.1 (conflict: heist => mtl>=2.0 && <2.1)
 rejecting: mtl-2.0.1.0, 2.0.0.0 (conflict: transformers==0.3.0.0, mtl =>
 transformers==0.2.*)
 rejecting: mtl-1.1.1.1, 1.1.1.0, 1.1.0.2, 1.1.0.1, 1.1.0.0, 1.0 (conflict:
 heist => mtl>=2.0 && <2.1)
 }}}
 When removing "bogus" from the build-depends, cabal-install is able to
 come up with a working install plan.

 Used versions:
 {{{
 $ cabal --version
 cabal-install version 0.14.0
 using version 1.14.0 of the Cabal library
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/hackage/ticket/951>
Hackage <http://haskell.org/cabal/>
Hackage: Cabal and related projects