pyrox.dev
1# This file turns the pkgs/by-name directory (see its README.md for more info) into an overlay that adds all the defined packages.
2# No validity checks are done here,
3# instead this file is optimised for performance,
4# and validity checks are done by CI on PRs.
5
6# Type: Path -> Overlay
7baseDirectory:
8let
9 # Because of Nix's import-value cache, importing lib is free
10 lib = import ../../lib;
11
12 inherit (builtins)
13 readDir
14 ;
15
16 inherit (lib.attrsets)
17 mapAttrs
18 mapAttrsToList
19 mergeAttrsList
20 ;
21
22 # Package files for a single shard
23 # Type: String -> String -> AttrsOf Path
24 namesForShard =
25 shard: type:
26 if type != "directory" then
27 # Ignore all non-directories. Technically only README.md is allowed as a file in the base directory, so we could alternatively:
28 # - Assume that README.md is the only file and change the condition to `shard == "README.md"` for a minor performance improvement.
29 # This would however cause very poor error messages if there's other files.
30 # - Ensure that README.md is the only file, throwing a better error message if that's not the case.
31 # However this would make for a poor code architecture, because one type of error would have to be duplicated in the validity checks and here.
32 # Additionally in either of those alternatives, we would have to duplicate the hardcoding of "README.md"
33 { }
34 else
35 mapAttrs (name: _: baseDirectory + "/${shard}/${name}/package.nix") (
36 readDir (baseDirectory + "/${shard}")
37 );
38
39 # The attribute set mapping names to the package files defining them
40 # This is defined up here in order to allow reuse of the value (it's kind of expensive to compute)
41 # if the overlay has to be applied multiple times
42 packageFiles = mergeAttrsList (mapAttrsToList namesForShard (readDir baseDirectory));
43in
44# TODO: Consider optimising this using `builtins.deepSeq packageFiles`,
45# which could free up the above thunks and reduce GC times.
46# Currently this would be hard to measure until we have more packages
47# and ideally https://github.com/NixOS/nix/pull/8895
48self: super:
49{
50 # This attribute is necessary to allow CI to ensure that all packages defined in `pkgs/by-name`
51 # don't have an overriding definition in `all-packages.nix` with an empty (`{ }`) second `callPackage` argument.
52 # It achieves that with an overlay that modifies both `callPackage` and this attribute to signal whether `callPackage` is used
53 # and whether it's defined by this file here or `all-packages.nix`.
54 # TODO: This can be removed once `pkgs/by-name` can handle custom `callPackage` arguments without `all-packages.nix` (or any other way of achieving the same result).
55 # Because at that point the code in ./stage.nix can be changed to not allow definitions in `all-packages.nix` to override ones from `pkgs/by-name` anymore and throw an error if that happens instead.
56 _internalCallByNamePackageFile = file: self.callPackage file { };
57}
58// mapAttrs (name: self._internalCallByNamePackageFile) packageFiles