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nixpkgs/pkgs/development/haskell-modules/make-package-set.nix
Georges Dubus 2645e1a1eb cabal2nix: split into a lightweight version and a wrapper
Current, the `cabal2nix` derivation contains both the executable, and a wrapper
that adds `nix` and `nix-prefetch-scripts`, which are required for some
features.

However, when calling `callCabal2nix` to create a derivation from a cabal file
at evaluation time,
these features are not actually used, but the huge closure of
`nix-prefetch-scripts` (which includes multiple vcs, as well as python and perl)
still needs to be fetched.

This commit splits cabal2nix into a lightweight version that is a standalone
static binary (`cabal2nix-unwrapped`), and a wrapper that includes the proper
dependencies in the path for full usage of the command line
utility (`cabal2nix`).

This commit also switches to the default ghc, to reduce the likelyhood of
building a different ghc when calling `callCabal2nix`.
2020-03-13 20:18:14 +01:00

330 lines
12 KiB
Nix

# This expression takes a file like `hackage-packages.nix` and constructs
# a full package set out of that.
{ # package-set used for build tools (all of nixpkgs)
buildPackages
, # A haskell package set for Setup.hs, compiler plugins, and similar
# build-time uses.
buildHaskellPackages
, # package-set used for non-haskell dependencies (all of nixpkgs)
pkgs
, # stdenv to use for building haskell packages
stdenv
, haskellLib
, # hashes for downloading Hackage packages
all-cabal-hashes
, # compiler to use
ghc
, # A function that takes `{ pkgs, stdenv, callPackage }` as the first arg and
# `self` as second, and returns a set of haskell packages
package-set
, # The final, fully overriden package set usable with the nixpkgs fixpoint
# overriding functionality
extensible-self
}:
# return value: a function from self to the package set
self:
let
inherit (stdenv) buildPlatform hostPlatform;
inherit (stdenv.lib) fix' extends makeOverridable;
inherit (haskellLib) overrideCabal;
mkDerivationImpl = pkgs.callPackage ./generic-builder.nix {
inherit stdenv;
nodejs = buildPackages.nodejs-slim;
inherit (self) buildHaskellPackages ghc ghcWithHoogle ghcWithPackages;
inherit (self.buildHaskellPackages) jailbreak-cabal;
hscolour = overrideCabal self.buildHaskellPackages.hscolour (drv: {
isLibrary = false;
doHaddock = false;
hyperlinkSource = false; # Avoid depending on hscolour for this build.
postFixup = "rm -rf $out/lib $out/share $out/nix-support";
});
cpphs = overrideCabal (self.cpphs.overrideScope (self: super: {
mkDerivation = drv: super.mkDerivation (drv // {
enableSharedExecutables = false;
enableSharedLibraries = false;
doHaddock = false;
useCpphs = false;
});
})) (drv: {
isLibrary = false;
postFixup = "rm -rf $out/lib $out/share $out/nix-support";
});
};
mkDerivation = makeOverridable mkDerivationImpl;
# manualArgs are the arguments that were explictly passed to `callPackage`, like:
#
# callPackage foo { bar = null; };
#
# here `bar` is a manual argument.
callPackageWithScope = scope: fn: manualArgs:
let
# this code is copied from callPackage in lib/customisation.nix
#
# we cannot use `callPackage` here because we want to call `makeOverridable`
# on `drvScope` (we cannot add `overrideScope` after calling `callPackage` because then it is
# lost on `.override`) but determine the auto-args based on `drv` (the problem here
# is that nix has no way to "passthrough" args while preserving the reflection
# info that callPackage uses to determine the arguments).
drv = if stdenv.lib.isFunction fn then fn else import fn;
auto = builtins.intersectAttrs (stdenv.lib.functionArgs drv) scope;
# this wraps the `drv` function to add a `overrideScope` function to the result.
drvScope = allArgs: drv allArgs // {
overrideScope = f:
let newScope = mkScope (fix' (extends f scope.__unfix__));
# note that we have to be careful here: `allArgs` includes the auto-arguments that
# weren't manually specified. If we would just pass `allArgs` to the recursive call here,
# then we wouldn't look up any packages in the scope in the next interation, because it
# appears as if all arguments were already manually passed, so the scope change would do
# nothing.
in callPackageWithScope newScope drv manualArgs;
};
in stdenv.lib.makeOverridable drvScope (auto // manualArgs);
mkScope = scope: let
ps = pkgs.__splicedPackages;
scopeSpliced = pkgs.splicePackages {
pkgsBuildBuild = scope.buildHaskellPackages.buildHaskellPackages;
pkgsBuildHost = scope.buildHaskellPackages;
pkgsBuildTarget = {};
pkgsHostHost = {};
pkgsHostTarget = scope;
pkgsTargetTarget = {};
} // {
# Don't splice these
inherit (scope) ghc buildHaskellPackages;
};
in ps // ps.xorg // ps.gnome2 // { inherit stdenv; } // scopeSpliced;
defaultScope = mkScope self;
callPackage = drv: args: callPackageWithScope defaultScope drv args;
withPackages = packages: buildPackages.callPackage ./with-packages-wrapper.nix {
inherit (self) ghc llvmPackages;
inherit packages;
};
# Use cabal2nix to create a default.nix for the package sources found at 'src'.
haskellSrc2nix = { name, src, sha256 ? null, extraCabal2nixOptions ? "" }:
let
sha256Arg = if sha256 == null then "--sha256=" else ''--sha256="${sha256}"'';
in buildPackages.stdenv.mkDerivation {
name = "cabal2nix-${name}";
nativeBuildInputs = [ buildPackages.cabal2nix-unwrapped ];
preferLocalBuild = true;
allowSubstitutes = false;
phases = ["installPhase"];
LANG = "en_US.UTF-8";
LOCALE_ARCHIVE = pkgs.lib.optionalString (buildPlatform.libc == "glibc") "${buildPackages.glibcLocales}/lib/locale/locale-archive";
installPhase = ''
export HOME="$TMP"
mkdir -p "$out"
cabal2nix --compiler=${self.ghc.haskellCompilerName} --system=${hostPlatform.config} ${sha256Arg} "${src}" ${extraCabal2nixOptions} > "$out/default.nix"
'';
};
all-cabal-hashes-component = name: version: buildPackages.runCommand "all-cabal-hashes-component-${name}-${version}" {} ''
tar --wildcards -xzvf ${all-cabal-hashes} \*/${name}/${version}/${name}.{json,cabal}
mkdir -p $out
mv */${name}/${version}/${name}.{json,cabal} $out
'';
hackage2nix = name: version: let component = all-cabal-hashes-component name version; in self.haskellSrc2nix {
name = "${name}-${version}";
sha256 = ''$(sed -e 's/.*"SHA256":"//' -e 's/".*$//' "${component}/${name}.json")'';
src = "${component}/${name}.cabal";
};
# Adds a nix file as an input to the haskell derivation it
# produces. This is useful for callHackage / callCabal2nix to
# prevent the generated default.nix from being garbage collected
# (requiring it to be frequently rebuilt), which can be an
# annoyance.
callPackageKeepDeriver = src: args:
overrideCabal (self.callPackage src args) (orig: {
preConfigure = ''
# Generated from ${src}
${orig.preConfigure or ""}
'';
passthru = orig.passthru or {} // {
# When using callCabal2nix or callHackage, it is often useful
# to debug a failure by inspecting the Nix expression
# generated by cabal2nix. This can be accessed via this
# cabal2nixDeriver field.
cabal2nixDeriver = src;
};
});
in package-set { inherit pkgs stdenv callPackage; } self // {
inherit mkDerivation callPackage haskellSrc2nix hackage2nix buildHaskellPackages;
inherit (haskellLib) packageSourceOverrides;
# callHackage :: Text -> Text -> AttrSet -> HaskellPackage
#
# e.g., while overriding a package set:
# '... foo = self.callHackage "foo" "1.5.3" {}; ...'
callHackage = name: version: callPackageKeepDeriver (self.hackage2nix name version);
# callHackageDirect
# :: { pkg :: Text, ver :: Text, sha256 :: Text }
# -> AttrSet
# -> HaskellPackage
#
# This function does not depend on all-cabal-hashes and therefore will work
# for any version that has been released on hackage as opposed to only
# versions released before whatever version of all-cabal-hashes you happen
# to be currently using.
callHackageDirect = {pkg, ver, sha256}:
let pkgver = "${pkg}-${ver}";
in self.callCabal2nix pkg (pkgs.fetchzip {
url = "mirror://hackage/${pkgver}/${pkgver}.tar.gz";
inherit sha256;
});
# Creates a Haskell package from a source package by calling cabal2nix on the source.
callCabal2nixWithOptions = name: src: extraCabal2nixOptions: args:
let
filter = path: type:
pkgs.lib.hasSuffix "${name}.cabal" path ||
baseNameOf path == "package.yaml";
expr = self.haskellSrc2nix {
inherit name extraCabal2nixOptions;
src = if pkgs.lib.canCleanSource src
then pkgs.lib.cleanSourceWith { inherit src filter; }
else src;
};
in overrideCabal (callPackageKeepDeriver expr args) (orig: {
inherit src;
});
callCabal2nix = name: src: args: self.callCabal2nixWithOptions name src "" args;
# : { root : Path
# , name : Defaulted String
# , source-overrides : Defaulted (Either Path VersionNumber)
# , overrides : Defaulted (HaskellPackageOverrideSet)
# , modifier : Defaulted
# , returnShellEnv : Defaulted
# } -> NixShellAwareDerivation
# Given a path to a haskell package directory, an optional package name
# which defaults to the base name of the path, an optional set of source
# overrides as appropriate for the 'packageSourceOverrides' function, an
# optional set of arbitrary overrides, and an optional haskell package
# modifier, return a derivation appropriate for nix-build or nix-shell to
# build that package.
developPackage =
{ root
, name ? builtins.baseNameOf root
, source-overrides ? {}
, overrides ? self: super: {}
, modifier ? drv: drv
, returnShellEnv ? pkgs.lib.inNixShell }:
let drv =
(extensible-self.extend
(pkgs.lib.composeExtensions
(self.packageSourceOverrides source-overrides)
overrides))
.callCabal2nix name root {};
in if returnShellEnv then (modifier drv).env else modifier drv;
ghcWithPackages = selectFrom: withPackages (selectFrom self);
ghcWithHoogle = selectFrom:
let
packages = selectFrom self;
hoogle = callPackage ./hoogle.nix {
inherit packages;
};
in withPackages (packages ++ [ hoogle ]);
# Returns a derivation whose environment contains a GHC with only
# the dependencies of packages listed in `packages`, not the
# packages themselves. Using nix-shell on this derivation will
# give you an environment suitable for developing the listed
# packages with an incremental tool like cabal-install.
# In addition to the "packages" arg and "withHoogle" arg, anything that
# can be passed into stdenv.mkDerivation can be included in the input attrset
#
# # default.nix
# with import <nixpkgs> {};
# haskellPackages.extend (haskell.lib.packageSourceOverrides {
# frontend = ./frontend;
# backend = ./backend;
# common = ./common;
# })
#
# # shell.nix
# let pkgs = import <nixpkgs> {} in
# (import ./.).shellFor {
# packages = p: [p.frontend p.backend p.common];
# withHoogle = true;
# buildInputs = [ pkgs.python ];
# }
#
# -- cabal.project
# packages:
# frontend/
# backend/
# common/
#
# bash$ nix-shell --run "cabal new-build all"
# bash$ nix-shell --run "python"
shellFor = { packages, withHoogle ? false, ... } @ args:
let
combinedPackageFor = packages:
let
selected = packages self;
pname = if pkgs.lib.length selected == 1
then (pkgs.lib.head selected).name
else "packages";
# If `packages = [ a b ]` and `a` depends on `b`, don't build `b`,
# because cabal will end up ignoring that built version, assuming
# new-style commands.
combinedPackages = pkgs.lib.filter
(input: pkgs.lib.all (p: input.outPath or null != p.outPath) selected);
# Returns an attrset containing a combined list packages' inputs for each
# stage of the build process
packageInputs = pkgs.lib.zipAttrsWith
(_: pkgs.lib.concatMap combinedPackages)
(map (p: p.getCabalDeps) selected);
genericBuilderArgs = {
inherit pname;
version = "0";
license = null;
} // packageInputs;
in self.mkDerivation genericBuilderArgs;
mkDerivationArgs = builtins.removeAttrs args [ "packages" "withHoogle" ];
in ((combinedPackageFor packages).envFunc { inherit withHoogle; }).overrideAttrs (old: mkDerivationArgs // {
nativeBuildInputs = old.nativeBuildInputs ++ mkDerivationArgs.nativeBuildInputs or [];
buildInputs = old.buildInputs ++ mkDerivationArgs.buildInputs or [];
});
ghc = ghc // {
withPackages = self.ghcWithPackages;
withHoogle = self.ghcWithHoogle;
};
}