[Hackage] #604: a feature to explicitly allow multiple versions of a single dependency

[Hackage]

#604: a feature to explicitly allow multiple versions of a single dependency
----------------------------+-----------------------------------------------
  Reporter:  guest          |        Owner:         
      Type:  enhancement    |       Status:  new    
  Priority:  normal         |    Milestone:         
 Component:  Cabal library  |      Version:  1.6.0.1
  Severity:  normal         |     Keywords:         
Difficulty:  unknown        |   Ghcversion:  6.10.1 
  Platform:  Linux          |  
----------------------------+-----------------------------------------------
 I wanted to build two executables for comparing the performance difference
 between happstack-server-0.3.4 and happstack-server-0.4. So I wrote below
 cabal file but found that cabal cannot build what I want. Here is the
 output for "cabal configure":

 {{{
 aycan at fgt:~/haskell/tests/happstack-tests$ cabal configure
 Resolving dependencies...
 Configuring happstack-tests-0.1...
 cabal: At least the following dependencies are missing:
 happstack-server ==0.4 && ==0.3.4
 }}}


 {{{
 Name: happstack-tests
 Version: 0.1
 Author: Aycan iRiCAN <aycan.irican at core.gen.tr>
 Stability: Experimental
 Category: Web
 Synopsis: Tests for Happstack Packages
 Cabal-version: >= 1.6
 Build-Type: Simple

 Flag base4
     Description: Choose the even newer, even smaller, split-up base
 package.

 Executable hello-0.3.3
   Main-Is: Hello.hs
   Hs-source-dirs: happstack-server
   GHC-options: -threaded -Wall -Wwarn -O2 -fwarn-tabs -fwarn-unused-
 imports
   Build-depends:
      base
    , happstack-server == 0.3.4

 Executable hello-0.4
   Main-Is: Hello.hs
   Hs-source-dirs: happstack-server
   GHC-options: -threaded -Wall -Wwarn -O2 -fwarn-tabs -fwarn-unused-
 imports
   Build-depends:
      base
    , happstack-server == 0.4
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/hackage/ticket/604>
Hackage <http://haskell.org/cabal/>
Hackage: Cabal and related projects