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90 lines
3.6 KiB
Nix
90 lines
3.6 KiB
Nix
/* Impure default args for `pkgs/top-level/default.nix`. See that file
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for the meaning of each argument. */
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with builtins;
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let
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homeDir = builtins.getEnv "HOME";
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# Return ‘x’ if it evaluates, or ‘def’ if it throws an exception.
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try = x: def: let res = tryEval x; in if res.success then res.value else def;
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in
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{ # We combine legacy `system` and `platform` into `localSystem`, if
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# `localSystem` was not passed. Strictly speaking, this is pure desugar, but
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# it is most convient to do so before the impure `localSystem.system` default,
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# so we do it now.
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localSystem ? builtins.intersectAttrs { system = null; platform = null; } args
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, # These are needed only because nix's `--arg` command-line logic doesn't work
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# with unnamed parameters allowed by ...
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system ? localSystem.system
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, platform ? localSystem.platform
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, crossSystem ? null
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, # Fallback: The contents of the configuration file found at $NIXPKGS_CONFIG or
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# $HOME/.config/nixpkgs/config.nix.
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config ? let
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configFile = getEnv "NIXPKGS_CONFIG";
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configFile2 = homeDir + "/.config/nixpkgs/config.nix";
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configFile3 = homeDir + "/.nixpkgs/config.nix"; # obsolete
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in
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if configFile != "" && pathExists configFile then import configFile
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else if homeDir != "" && pathExists configFile2 then import configFile2
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else if homeDir != "" && pathExists configFile3 then import configFile3
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else {}
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, # Overlays are used to extend Nixpkgs collection with additional
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# collections of packages. These collection of packages are part of the
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# fix-point made by Nixpkgs.
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overlays ? let
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isDir = path: pathExists (path + "/.");
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pathOverlays = try (toString <nixpkgs-overlays>) "";
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homeOverlaysFile = homeDir + "/.config/nixpkgs/overlays.nix";
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homeOverlaysDir = homeDir + "/.config/nixpkgs/overlays";
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overlays = path:
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# check if the path is a directory or a file
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if isDir path then
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# it's a directory, so the set of overlays from the directory, ordered lexicographically
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let content = readDir path; in
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map (n: import (path + ("/" + n)))
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(builtins.filter (n: builtins.match ".*\\.nix" n != null || pathExists (path + ("/" + n + "/default.nix")))
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(attrNames content))
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else
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# it's a file, so the result is the contents of the file itself
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import path;
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in
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if pathOverlays != "" && pathExists pathOverlays then overlays pathOverlays
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else if pathExists homeOverlaysFile && pathExists homeOverlaysDir then
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throw ''
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Nixpkgs overlays can be specified with ${homeOverlaysFile} or ${homeOverlaysDir}, but not both.
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Please remove one of them and try again.
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''
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else if pathExists homeOverlaysFile then
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if isDir homeOverlaysFile then
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throw (homeOverlaysFile + " should be a file")
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else overlays homeOverlaysFile
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else if pathExists homeOverlaysDir then
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if !(isDir homeOverlaysDir) then
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throw (homeOverlaysDir + " should be a directory")
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else overlays homeOverlaysDir
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else []
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, crossOverlays ? []
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, ...
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} @ args:
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# If `localSystem` was explicitly passed, legacy `system` and `platform` should
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# not be passed.
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assert args ? localSystem -> !(args ? system || args ? platform);
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import ./. (builtins.removeAttrs args [ "system" "platform" ] // {
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inherit config overlays crossSystem crossOverlays;
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# Fallback: Assume we are building packages on the current (build, in GNU
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# Autotools parlance) system.
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localSystem = (if args ? localSystem then {}
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else { system = builtins.currentSystem; }) // localSystem;
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})
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