[GHC] #1963: Pressing ^C at the right moment can trash GHC's package list

[GHC]

#1963: Pressing ^C at the right moment can trash GHC's package list
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 Reporter:  igloo     |          Owner:  igloo  
     Type:  merge     |         Status:  closed 
 Priority:  normal    |      Milestone:  6.8.3  
Component:  Compiler  |        Version:  6.8.1  
 Severity:  normal    |     Resolution:  fixed  
 Keywords:            |     Difficulty:  Unknown
 Testcase:            |   Architecture:  Unknown
       Os:  Unknown   |  
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Comment (by duncan):

 Instead of the dodgy backing up of the old file, it should use the
 `writeFileAtomic` from Cabal. On Unix it is genuinely atomic (assuming ^C
 is turned into an exception) and on Windows there is a very narrow race
 condition but it's probably a good deal narrower than in `ghc-pkg`'s
 current impl.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1963#comment:4>
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