diff options
| -rw-r--r-- | pkgs/development/haskell-modules/generic-builder.nix | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/pkgs/development/haskell-modules/generic-builder.nix b/pkgs/development/haskell-modules/generic-builder.nix index edff84a0403c..c0505d6e3c63 100644 --- a/pkgs/development/haskell-modules/generic-builder.nix +++ b/pkgs/development/haskell-modules/generic-builder.nix @@ -72,7 +72,10 @@ let hasActiveLibrary = isLibrary && (enableStaticLibraries || enableSharedLibraries || enableLibraryProfiling); - enableParallelBuilding = versionOlder "7.10" ghc.version || (versionOlder "7.8" ghc.version && !hasActiveLibrary); + # We cannot enable -j<n> parallelism for libraries because GHC is far more + # likely to generate a non-determistic library ID in that case. Further + # details are at <https://github.com/peti/ghc-library-id-bug>. + enableParallelBuilding = versionOlder "7.8" ghc.version && !hasActiveLibrary; defaultConfigureFlags = [ "--verbose" "--prefix=$out" "--libdir=\\$prefix/lib/\\$compiler" "--libsubdir=\\$pkgid" |