nixpkgs/pkgs/development/haskell-modules/with-packages-wrapper.nix
Guillaume Bouchard abc4f961b4 haskellPackages.ghcWithPackages: fix for GHC 8.10
This closes #79441.

ghcWithPackages is using `ghc-pkg recache` to build its package
database. By doing so, it overrides the `package.cache[.lock]` files.

Details are unclear, but GHC 8.10 changed a bit the behavior.
Previously, it was unconditionally replacing the files by new ones. Now
it tries to open (for modification) the files. These files are symlinks
to another nix derivation, which is hence read-only.

This commit removes the files before running `ghc-pkg recache`, hence it
will just write the new files.

Tested with `haskellPackages.ghcWithPackages` (i.e. GHC 8.8) and
`haskell.packages.ghc8101.ghcWithPackages` (i.e GHC 8.10) with the
following nix file, at the root of the nixpkgs repository:

```
with import ./. {
  overlays = [
    (
      self: super: {
        haskellPackages = super.haskell.packages.ghc8101.override {
          overrides = selfh: superh: {
             th-lift-instances = super.haskell.lib.doJailbreak superh.th-lift-instances;
             th-expand-syns    = super.haskell.lib.doJailbreak superh.th-expand-syns;
             th-reify-many     = super.haskell.lib.doJailbreak superh.th-reify-many;
             th-orphans        = super.haskell.lib.doJailbreak superh.th-orphans;
             haskell-src-meta  = super.haskell.lib.doJailbreak superh.haskell-src-meta;
          };
        };
      }
  )
  ];
};
haskellPackages.ghcWithPackages(p:[p.PyF])
```

This will test with GHC 8.10. Comment out the `overlays` to test with
GHC 8.8.
2020-04-17 20:50:48 +02:00

155 lines
6.5 KiB
Nix

{ lib, stdenv, ghc, llvmPackages, packages, symlinkJoin, makeWrapper
, withLLVM ? false
, postBuild ? ""
, ghcLibdir ? null # only used by ghcjs, when resolving plugins
}:
assert ghcLibdir != null -> (ghc.isGhcjs or false);
# This wrapper works only with GHC 6.12 or later.
assert lib.versionOlder "6.12" ghc.version || ghc.isGhcjs || ghc.isHaLVM;
# It's probably a good idea to include the library "ghc-paths" in the
# compiler environment, because we have a specially patched version of
# that package in Nix that honors these environment variables
#
# NIX_GHC
# NIX_GHCPKG
# NIX_GHC_DOCDIR
# NIX_GHC_LIBDIR
#
# instead of hard-coding the paths. The wrapper sets these variables
# appropriately to configure ghc-paths to point back to the wrapper
# instead of to the pristine GHC package, which doesn't know any of the
# additional libraries.
#
# A good way to import the environment set by the wrapper below into
# your shell is to add the following snippet to your ~/.bashrc:
#
# if [ -e ~/.nix-profile/bin/ghc ]; then
# eval $(grep export ~/.nix-profile/bin/ghc)
# fi
let
isGhcjs = ghc.isGhcjs or false;
isHaLVM = ghc.isHaLVM or false;
ghc761OrLater = isGhcjs || isHaLVM || lib.versionOlder "7.6.1" ghc.version;
packageDBFlag = if ghc761OrLater then "--global-package-db" else "--global-conf";
ghcCommand' = if isGhcjs then "ghcjs" else "ghc";
ghcCommand = "${ghc.targetPrefix}${ghcCommand'}";
ghcCommandCaps= lib.toUpper ghcCommand';
libDir = if isHaLVM then "$out/lib/HaLVM-${ghc.version}"
else "$out/lib/${ghcCommand}-${ghc.version}";
docDir = "$out/share/doc/ghc/html";
packageCfgDir = "${libDir}/package.conf.d";
paths = lib.filter (x: x ? isHaskellLibrary) (lib.closePropagation packages);
hasLibraries = lib.any (x: x.isHaskellLibrary) paths;
# CLang is needed on Darwin for -fllvm to work:
# https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/codegens.html#llvm-code-generator-fllvm
llvm = lib.makeBinPath
([ llvmPackages.llvm ]
++ lib.optional stdenv.targetPlatform.isDarwin llvmPackages.clang);
in
if paths == [] && !withLLVM then ghc else
symlinkJoin {
# this makes computing paths from the name attribute impossible;
# if such a feature is needed, the real compiler name should be saved
# as a dedicated drv attribute, like `compiler-name`
name = ghc.name + "-with-packages";
paths = paths ++ [ghc];
postBuild = ''
. ${makeWrapper}/nix-support/setup-hook
# wrap compiler executables with correct env variables
for prg in ${ghcCommand} ${ghcCommand}i ${ghcCommand}-${ghc.version} ${ghcCommand}i-${ghc.version}; do
if [[ -x "${ghc}/bin/$prg" ]]; then
rm -f $out/bin/$prg
makeWrapper ${ghc}/bin/$prg $out/bin/$prg \
--add-flags '"-B$NIX_${ghcCommandCaps}_LIBDIR"' \
--set "NIX_${ghcCommandCaps}" "$out/bin/${ghcCommand}" \
--set "NIX_${ghcCommandCaps}PKG" "$out/bin/${ghcCommand}-pkg" \
--set "NIX_${ghcCommandCaps}_DOCDIR" "${docDir}" \
--set "NIX_${ghcCommandCaps}_LIBDIR" "${libDir}" \
${lib.optionalString (ghc.isGhcjs or false)
''--set NODE_PATH "${ghc.socket-io}/lib/node_modules"''
} \
${lib.optionalString withLLVM ''--prefix "PATH" ":" "${llvm}"''}
fi
done
for prg in runghc runhaskell; do
if [[ -x "${ghc}/bin/$prg" ]]; then
rm -f $out/bin/$prg
makeWrapper ${ghc}/bin/$prg $out/bin/$prg \
--add-flags "-f $out/bin/${ghcCommand}" \
--set "NIX_${ghcCommandCaps}" "$out/bin/${ghcCommand}" \
--set "NIX_${ghcCommandCaps}PKG" "$out/bin/${ghcCommand}-pkg" \
--set "NIX_${ghcCommandCaps}_DOCDIR" "${docDir}" \
--set "NIX_${ghcCommandCaps}_LIBDIR" "${libDir}"
fi
done
for prg in ${ghcCommand}-pkg ${ghcCommand}-pkg-${ghc.version}; do
if [[ -x "${ghc}/bin/$prg" ]]; then
rm -f $out/bin/$prg
makeWrapper ${ghc}/bin/$prg $out/bin/$prg --add-flags "${packageDBFlag}=${packageCfgDir}"
fi
done
# haddock was referring to the base ghc, https://github.com/NixOS/nixpkgs/issues/36976
if [[ -x "${ghc}/bin/haddock" ]]; then
rm -f $out/bin/haddock
makeWrapper ${ghc}/bin/haddock $out/bin/haddock \
--add-flags '"-B$NIX_${ghcCommandCaps}_LIBDIR"' \
--set "NIX_${ghcCommandCaps}_LIBDIR" "${libDir}"
fi
'' + (lib.optionalString (stdenv.targetPlatform.isDarwin && !isGhcjs && !stdenv.targetPlatform.isiOS) ''
# Work around a linker limit in macOS Sierra (see generic-builder.nix):
local packageConfDir="$out/lib/${ghc.name}/package.conf.d";
local dynamicLinksDir="$out/lib/links"
mkdir -p $dynamicLinksDir
# Clean up the old links that may have been (transitively) included by
# symlinkJoin:
rm -f $dynamicLinksDir/*
for d in $(grep dynamic-library-dirs $packageConfDir/*|awk '{print $2}'|sort -u); do
ln -s $d/*.dylib $dynamicLinksDir
done
for f in $packageConfDir/*.conf; do
# Initially, $f is a symlink to a read-only file in one of the inputs
# (as a result of this symlinkJoin derivation).
# Replace it with a copy whose dynamic-library-dirs points to
# $dynamicLinksDir
cp $f $f-tmp
rm $f
sed "s,dynamic-library-dirs: .*,dynamic-library-dirs: $dynamicLinksDir," $f-tmp > $f
rm $f-tmp
done
'') + ''
${lib.optionalString hasLibraries ''
# GHC 8.10 changes.
# Instead of replacing package.cache[.lock] with the new file,
# ghc-pkg is now trying to open the file. These file are symlink
# to another nix derivation, so they are not writable. Removing
# them allow the correct behavior of ghc-pkg recache
# See: https://github.com/NixOS/nixpkgs/issues/79441
rm $out/lib/${ghc.name}/package.conf.d/package.cache.lock
rm $out/lib/${ghc.name}/package.conf.d/package.cache
$out/bin/${ghcCommand}-pkg recache
''}
${# ghcjs will read the ghc_libdir file when resolving plugins.
lib.optionalString (isGhcjs && ghcLibdir != null) ''
mkdir -p "${libDir}"
rm -f "${libDir}/ghc_libdir"
printf '%s' '${ghcLibdir}' > "${libDir}/ghc_libdir"
''}
$out/bin/${ghcCommand}-pkg check
'' + postBuild;
passthru = {
preferLocalBuild = true;
inherit (ghc) version meta;
};
}