[GHC] #8591: Concurrent executions of ghc-pkg can cause inconstant package.cache files

[GHC]

#8591: Concurrent executions of ghc-pkg can cause inconstant package.cache files
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              Reporter:  janm        |            Owner:  pgj
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  Package     |          Version:  7.6.3
  system                             |         Keywords:  ghc-pkg race
            Resolution:              |     Architecture:  Unknown/Multiple
      Operating System:  FreeBSD     |       Difficulty:  Unknown
       Type of failure:  Other       |       Blocked By:
             Test Case:              |  Related Tickets:
              Blocking:              |
Differential Revisions:              |
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Comment (by janm):

 Replying to [comment:8 pgj]:
 > Replying to [comment:5 janm]:
 > > I am running a test  build now but code inspection shows that the same
 race is present. I expect it to fail.
 >
 > All right, excellent, thanks.

 Interestingly enough it didn't fail. I suspect that it is because we have
 switch to pkg from the old-style packaging system on FreeBSD. We have
 local modifications to retry database access due to contention during
 package installation. This may be serialising execution of the Haskell
 installation processes.

 I will remove the JOBS limit in lang/ghc and rerun -- that should fail
 because there is no pkg database.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8591#comment:10>
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