paumr
a045d79264
After investigating adding a project argument to override the mapping of libs to packages we realised we could fix the X11 package by updating `modules/configuration-nix.nix`. We also updated `system-nixpkgs-map.nix` to allow multiple packages to be mapped for a single library (turned out not to be necessary for X11). Co-authored-by: Rodney Lorrimar <rodney.lorrimar@iohk.io> Co-authored-by: Hamish Mackenzie <Hamish.Mackenzie@iohk.io>
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Mapping non-Haskell dependencies to Nixpkgs
Cabal files may contain dependencies to external non-Haskell dependencies via:
If there is a pkgs attribute in Nixpkgs that matches the name given
in the Cabal file, then it will be added as a dependency (see the
output of cabal-to-nix). Otherwise, there needs to be a mapping from
Cabal file names (decided by the package author) to Nix package
identifiers.
Nixpkgs overlay
The user may solve it by themself by overriding Nixpkgs and adding a package alias. For example:
nixpkgs.overlays = [
(self: super: {
icuuc = self.icu;
icui18n = self.icu;
icudata = self.icu;
})
];
Replace libraries of components
If a component is missing a dependency it can be added via modules. For example:
project = pkgs.haskell-nix.project' {
src = self;
compiler-nix-name = "ghc8102";
modules = [{
# Replace `extra-libraries` dependencies
packages.X11.components.library.libs = pkgs.lib.mkForce (with pkgs.xorg;
[ libX11 libXrandr libXext libXScrnSaver libXinerama ]);
}];
};
Mapping in Haskell.nix
Alternatively, if the name is commonly used, an alias can be added to the Haskell.nix sources, so that it's solved for all users.
-
lib/pkgconf-nixpkgs-map.nix— forpkgconfig-depends.Each mapping entry is a list of packages.
-
lib/system-nixpkgs-map.nix— forbuild-tool-depends,frameworks,extra-libraries, etc.Each name can be mapped to:
- A single package from nixkpgs.
null— eliminates the dependency- A list of packages — sometimes needed for dependencies such as
X11.
!!! tip "Open a PR" Please go ahead and open a pull request to improve the package mappings.