Re: [GHC] #9963: GHCi panic with --print-libdir flag

#9963: GHCi panic with --print-libdir flag -------------------------------------+------------------------------------- Reporter: jstolarek | Owner: thomie Type: bug | Status: patch Priority: high | Milestone: 7.10.1 Component: Driver | Version: 7.9 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: GHCi crash | Unknown/Multiple Blocked By: | Test Case: Related Tickets: | driver/T9963 | Blocking: | Differential Revisions: Phab:D730 -------------------------------------+------------------------------------- Comment (by Thomas Miedema ): In [changeset:"5166ee94e439375a4e6acb80f88ec6ee65476bbd/ghc"]: {{{ #!CommitTicketReference repository="ghc" revision="5166ee94e439375a4e6acb80f88ec6ee65476bbd" Dont call unsafeGlobalDynFlags if it is not set Parsing of static and mode flags happens before any session is started, i.e., before the first call to 'GHC.withGhc'. Therefore, to report errors for invalid usage of these two types of flags, we can not call any function that needs DynFlags, as there are no DynFlags available yet (unsafeGlobalDynFlags is not set either). So we always print "on the commandline" as the location, which is true except for Api users, which is probably ok. When reporting errors for invalid usage of dynamic flags we /can/ make use of DynFlags, and we do so explicitly in DynFlags.parseDynamicFlagsFull. Before, we called unsafeGlobalDynFlags when an invalid (combination of) flag(s) was given on the commandline, resulting in panics (#9963). This regression was introduced in 1d6124de. Also rename showSDocSimple to showSDocUnsafe, to hopefully prevent this from happening again. Reviewed By: austin Differential Revision: https://phabricator.haskell.org/D730 GHC Trac Issues: #9963 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9963#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler