July 2025 - ghc-devs - Haskell.org

Reproducing a build failure
by Simon Peyton Jones 11 Jul '25

11 Jul '25

Friends In !14410, specifically on Fedora, I get this build failure <https://gitlab.haskell.org/ghc/ghc/-/jobs/2225860>. Some kind of crash in some invocation of Haddock to make the docs for ghc-internal. Question: how can I reproduce this failure on my own machine? It builds fine for me. Thanks Simon Error when running Shake build system: at want, called at src/Main.hs:127:44 in main:Main * Depends on: binary-dist at need, called at src/Rules/BinaryDist.hs:311:13 in main:Rules.BinaryDist * Depends on: binary-dist-dir at need, called at src/Rules/BinaryDist.hs:168:9 in main:Rules.BinaryDist * Depends on: docs at need, called at src/Rules/Documentation.hs:137:9 in main:Rules.Documentation * Depends on: _build/doc/html/index.html at need, called at src/Rules/Documentation.hs:214:9 in main:Rules.Documentation * Depends on: _build/doc/html/libraries/index.html at need, called at src/Rules/Documentation.hs:251:9 in main:Rules.Documentation * Depends on: _build/doc/html/libraries/ghc-internal-9.1400.0-9f99/ghc-internal.haddock at cmd, called at src/Builder.hs:404:5 in main:Builder * Raised the exception: Development.Shake.cmd, system command failed Command line: _build/stage1/bin/haddock --verbosity=0 -B_build/stage1/lib --lib=_build/stage1/lib --odir=_build/doc/html/libraries/ghc-internal-9.1400.0-9f99 --dump-interface=_build/doc/html/libraries/ghc-internal-9.1400.0-9f99/ghc-internal.haddock --html '--title=ghc-internal-9.1400.0: Basic libraries' --prologue=_build/doc/html/libraries/ghc-internal-9.1400.0-9f99/haddock-prologue.txt --optghc=-D__HADDOCK_VERSION__=2300 --hide=GHC.Internal.Data.Typeable.Internal --hide=GHC.Internal.IO.Handle.Lock.Common --hide=GHC.Internal.IO.Handle.Lock.Flock --hide=GHC.Internal.IO.Handle.Lock.LinuxOFD --hide=GHC.Internal.IO.Handle.Lock.NoOp --hide=GHC.Internal.IO.Handle.Lock.Windows --hide=GHC.Internal.StaticPtr.Internal --hide=GHC.Internal.Event.Arr --hide=GHC.Internal.Event.Array --hide=GHC.Internal.Event.Internal --hide=GHC.Internal.Event.Internal.Types --hide=GHC.Internal.Event.IntTable --hide=GHC.Internal.Event.IntVar --hide=GHC.Internal.Event.PSQ --hide=GHC.Internal.Event.Unique --hide=GHC.Internal.Unicode.Bits --hide=GHC.Internal.Unicode.Char.DerivedCoreProperties --hide=GHC.Internal.Unicode.Char.UnicodeData.GeneralCategory --hide=GHC.Internal.Unicode.Char.UnicodeData.SimpleLowerCaseMapping --hide=GHC.Internal.Unicode.Char.UnicodeData.SimpleTitleCaseMapping --hide=GHC.Internal.Unicode.Char.UnicodeData.SimpleUpperCaseMapping --hide=GHC.Internal.Unicode.Version --hide=GHC.Internal.System.Environment.ExecutablePath --hide=GHC.Internal.Bignum.Backend.GMP --hide=GHC.Internal.Event.Control --hide=GHC.Internal.Event.EPoll --hide=GHC.Internal.Event.KQueue --hide=GHC.Internal.Event.Manager --hide=GHC.Internal.Event.Poll --hide=GHC.Internal.Event.Thread --hide=GHC.Internal.Event.TimerManager --optghc=-hisuf --optghc=dyn_hi --optghc=-osuf --optghc=dyn_o --optghc=-hcsuf --optghc=dyn_hc --optghc=-fPIC --optghc=-dynamic --optghc=-hide-all-packages --optghc=-no-user-package-db '--optghc=-package-env -' '--optghc=-this-unit-id ghc-internal-9.1400.0-9f99' '--optghc=-this-package-name ghc-internal' '--optghc=-package-id rts-1.0.3' --optghc=-i --optghc=-i/builds/ghc/ghc/_build/stage1/libraries/ghc-internal/build --optghc=-i/builds/ghc/ghc/_build/stage1/libraries/ghc-internal/build/autogen --optghc=-i/builds/ghc/ghc/libraries/ghc-internal/src --optghc=-Irts/include --optghc=-I_build/stage1/libraries/ghc-internal/build --optghc=-I_build/stage1/libraries/ghc-internal/build/include --optghc=-Ilibraries/ghc-internal/include --optghc=-I/builds/ghc/ghc/rts/include --optghc=-I/builds/ghc/ghc/_build/stage1/rts/build/include --optghc=-optP-include --optghc=-optP_build/stage1/libraries/ghc-internal/build/autogen/cabal_macros.h --optghc=-optP-DBIGNUM_GMP --optghc=-outputdir --optghc=_build/stage1/libraries/ghc-internal/build --optghc=-this-unit-id --optghc=ghc-internal --optghc=-Wcompat --optghc=-Wnoncanonical-monad-instances --optghc=-XHaskell2010 --optghc=-XNoImplicitPrelude --optghc=-no-global-package-db --optghc=-package-db=/builds/ghc/ghc/_build/stage1/inplace/package.conf.d --optghc=-ghcversion-file=rts/include/ghcversion.h --optghc=-ghcversion-file=rts/include/ghcversion.h --optghc=-this-unit-id --optghc=ghc-internal --optghc=-Wcompat --optghc=-Wnoncanonical-monad-instances --optghc=-XHaskell2010 --optghc=-XNoImplicitPrelude --optghc=-no-global-package-db --optghc=-package-db=/builds/ghc/ghc/_build/stage1/inplace/package.conf.d --optghc=-ghcversion-file=rts/include/ghcversion.h --optghc=-ghcversion-file=rts/include/ghcversion.h --optghc=-Wno-deprecated-flags --optghc=-Wno-trustworthy-safe +RTS -t_build/stage1/haddock-timing-files/ghc-internal.t --machine-readable -RTS --hyperlinked-source --hoogle --quickjump @/tmp/extra-file-54706448418404-4067-11690 Exit code: 1 Stderr: <no location info>: error: panic! (the 'impossible' happened) GHC version 9.14.0.20250710: idDetails a_alNe Call stack: CallStack (from HasCallStack): pprPanic, called at compiler/GHC/Types/Var.hs:1079:43 in ghc-9.14.0.20250710-7d78:GHC.Types.Var

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openFile gives "file is locked" error on Linux when creating a non-existing file
by Harendra Kumar 07 Jul '25

07 Jul '25

Hi everyone, We have a long standing, elusive and intermittent test failure in streamly's file system event test suite. The code where the error emanates from looks like this: createFileWithParent :: FilePath -> FilePath -> IO () createFileWithParent file parent = do let filepath = parent </> file let dir = takeDirectory filepath putStrLn $ "createFileWithParent: file [" ++ file ++ "] dir [" ++ dir ++ "]" putStrLn $ "Ensuring dir: " ++ dir createDirectoryIfMissing True dir r <- doesDirectoryExist dir if r then do putStrLn $ "Ensured dir: " ++ dir when (not (null file)) $ do exists <- doesFileExist filepath if not exists then do putStrLn $ "Creating file: " ++ (parent </> file) openFile (parent </> file) WriteMode >>= hClose putStrLn $ "Created file: " ++ (parent </> file) else error $ "File exists: " ++ filepath else error $ "Could not create dir: " ++ dir The important thing in the code above is that we check that the file does not exist already, and we are creating it. Creating this new file intermittently fails with the following error messages, all of these are coming from prints in the above: createFileWithParent: file [file1] dir [/tmp/fsevent_dir-e1098325dc2b0880/watch-root] Ensuring dir: /tmp/fsevent_dir-e1098325dc2b0880/watch-root Ensured dir: /tmp/fsevent_dir-e1098325dc2b0880/watch-root Creating file: /tmp/fsevent_dir-e1098325dc2b0880/watch-root/file1 uncaught exception: IOException of type ResourceBusy /tmp/fsevent_dir-e1098325dc2b0880/watch-root/file1: openFile: resource busy (file is locked) How can a file that does not exist and being created be locked during creation? We see this only on Linux, the same tests always succeed on Windows and macOS. We are facing this in GHC 9.2.8, I am not sure if it is version specific because in the past I selectively disabled the tests for specific GHC versions and the error still surfaced in other GHC versions. Anything obvious that we may be missing here? Any pointers or more debug info to generate to debug this? I have not started looking into the openFile code yet, hoping someone else knowing it well might help here. Is this some other "resource busy" error which is being wrongly bucketed into "file is locked" error? Thanks, Harendra

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CI hickups
by Andreas Klebinger 03 Jul '25

03 Jul '25

Hello devs, There are currently issues with the perf-notes repository tokken which cause CI pipelines to fail. If you see failures related to get being unable to fetch something this is the reason. We hope to fix this soon.

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