 fcaa408d00
			
		
	
	
		fcaa408d00
		
	
	
	
	
		
			
			Allows detecting whether attributes are overridden in all-packages.nix. In a future commit we'll use this to detect empty arguments being set in all-packages.nix and complain about that.
		
			
				
	
	
		
			60 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
			
		
		
	
	
			60 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
| # This file turns the pkgs/by-name directory (see its README.md for more info) into an overlay that adds all the defined packages.
 | |
| # No validity checks are done here,
 | |
| # instead this file is optimised for performance,
 | |
| # and validity checks are done by CI on PRs.
 | |
| 
 | |
| # Type: Path -> Overlay
 | |
| baseDirectory:
 | |
| let
 | |
|   # Because of Nix's import-value cache, importing lib is free
 | |
|   lib = import ../../lib;
 | |
| 
 | |
|   inherit (builtins)
 | |
|     readDir
 | |
|     ;
 | |
| 
 | |
|   inherit (lib.attrsets)
 | |
|     mapAttrs
 | |
|     mapAttrsToList
 | |
|     mergeAttrsList
 | |
|     ;
 | |
| 
 | |
|   # Package files for a single shard
 | |
|   # Type: String -> String -> AttrsOf Path
 | |
|   namesForShard = shard: type:
 | |
|     if type != "directory" then
 | |
|       # Ignore all non-directories. Technically only README.md is allowed as a file in the base directory, so we could alternatively:
 | |
|       # - Assume that README.md is the only file and change the condition to `shard == "README.md"` for a minor performance improvement.
 | |
|       #   This would however cause very poor error messages if there's other files.
 | |
|       # - Ensure that README.md is the only file, throwing a better error message if that's not the case.
 | |
|       #   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.
 | |
|       # Additionally in either of those alternatives, we would have to duplicate the hardcoding of "README.md"
 | |
|       { }
 | |
|     else
 | |
|       mapAttrs
 | |
|         (name: _: baseDirectory + "/${shard}/${name}/package.nix")
 | |
|         (readDir (baseDirectory + "/${shard}"));
 | |
| 
 | |
|   # The attribute set mapping names to the package files defining them
 | |
|   # This is defined up here in order to allow reuse of the value (it's kind of expensive to compute)
 | |
|   # if the overlay has to be applied multiple times
 | |
|   packageFiles = mergeAttrsList (mapAttrsToList namesForShard (readDir baseDirectory));
 | |
| in
 | |
| # TODO: Consider optimising this using `builtins.deepSeq packageFiles`,
 | |
| # which could free up the above thunks and reduce GC times.
 | |
| # Currently this would be hard to measure until we have more packages
 | |
| # and ideally https://github.com/NixOS/nix/pull/8895
 | |
| self: super:
 | |
| {
 | |
|   # This attribute is necessary to allow CI to ensure that all packages defined in `pkgs/by-name`
 | |
|   # don't have an overriding definition in `all-packages.nix` with an empty (`{ }`) second `callPackage` argument.
 | |
|   # It achieves that with an overlay that modifies both `callPackage` and this attribute to signal whether `callPackage` is used
 | |
|   # and whether it's defined by this file here or `all-packages.nix`.
 | |
|   # 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).
 | |
|   # 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.
 | |
|   _internalCallByNamePackageFile = file: self.callPackage file { };
 | |
| }
 | |
| // mapAttrs
 | |
|   (name: self._internalCallByNamePackageFile)
 | |
|   packageFiles
 |