[Hackage] #297: cabal fetch command don't fetch packages those have already been installed

[Hackage]

#297: cabal fetch command don't fetch packages those have already been installed
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  Reporter:  chylli              |        Owner:                 
      Type:  defect              |       Status:  new            
  Priority:  normal              |    Milestone:  Cabal-1.4      
 Component:  cabal-install tool  |      Version:                 
  Severity:  normal              |   Resolution:                 
  Keywords:                      |   Difficulty:  easy (<4 hours)
Ghcversion:  6.8.2               |     Platform:                 
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Comment (by Isaac Dupree):

 hang on, what is `cabal fetch` supposed to do?  Fetch[*] the source of:

 A. the package itself?

 B. the package and all its dependencies?

 C. the package and all its uninstalled dependencies?

 D. currently, it is, if I'm reading the code rightly: all the package's
 uninstalled dependencies (including itself if it's uninstalled), which is
 obviously wrong.

 I assumed from the help description that it meant "A" above, but then why
 is the code doing dependency analysis at all?  "B" = dep analyze with an
 empty set of "installed" packages, I suppose (would it be necessary to
 include the current "base" or similar in the installed-package-list
 though, since it's not on hackage?). "C" = just remove the named package
 from the installed-package-list (as Duncan said) -- but why would you want
 "C"?

 [*] fetch means, just make sure you have a copy of it in
 .cabal/packages/... -- if the source is already there then no need to
 download again

-- 
Ticket URL: <http://hackage.haskell.org/trac/hackage/ticket/297#comment:2>
Hackage <http://haskell.org/cabal/>
Hackage: Cabal and related projects