[GHC] #10550: Drop truncated package name prefix from package keys

[GHC]

#10550: Drop truncated package name prefix from package keys
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        Reporter:  ezyang            |                   Owner:  ezyang
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:  7.12.1
       Component:  Package system    |                 Version:  7.11
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  None/Unknown      |  Unknown/Multiple
      Blocked By:                    |               Test Case:
 Related Tickets:                    |                Blocking:
                                     |  Differential Revisions:
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Comment (by ezyang):

 Backwards compatibility considerations: GHC 7.10.1/7.10.2 will ship with
 libraries that are installed as `ghcpr_8TmvWUcS1U1IKHT0levwg3`, so Cabal
 will need to continue to understand this format.  However, GHC is
 indifferent to how you pick future `-this-package-key`, so Cabal can
 simply generate `8TmvWUcS1U1IKHT0levwg3` for any subsequent installations
 and GHC wouldn't mind. (Old Cabal would not be able to read the package
 database however, because the parser is not setup to understand
 `8TmvWUcS1U1IKHT0levwg3`, but `ghc-pkg` doesn't validate the format so
 this would simply translate into not being able to use Cabal to manage a
 more recent package database, which I think already applies.)

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10550#comment:3>
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