#8591: Concurrent executions of ghc-pkg can cause inconstant package.cache files -------------------------------------+------------------------------------- Reporter: janm | Owner: pgj Type: bug | Status: new Priority: normal | Milestone: Component: Package system | Version: 7.6.3 Resolution: | Keywords: ghc-pkg Operating System: Unknown/Multiple | race Type of failure: Other | Architecture: Blocked By: | Unknown/Multiple Related Tickets: #10205 | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Changes (by thomie): * os: FreeBSD => Unknown/Multiple * related: => #10205 Comment: janm: are you installing the packages with cabal or manually? The GHC build system (in ghc.mk) contains the following comment: {{{ # register the boot packages in strict sequence, because running # multiple ghc-pkgs in parallel doesn't work (registrations may get # lost). }}} Presumably `cabal -j` also registers the packages sequentially, or there'd be many more reported issues. Changing just `withFileAtomic` as you propose in comment:2 and comment:5 wouldn't solve the problem. Two concurrent ghc-pkg processes still wouldn't know about each other's modifications to the package database, so the last one to call `withFileAtomic` would still win. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8591#comment:11 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler