top-level: Simplify impure and pure fallback

This is now possible, since the `platform` attribute has been removed in
PR #107214. I've been waiting to do a cleanup like this for a long time!
This commit is contained in:
John Ericson 2021-01-22 16:36:06 -05:00
parent 9c213398b3
commit 2dde58903e
2 changed files with 24 additions and 34 deletions

View file

@ -1,9 +1,8 @@
/* This function composes the Nix Packages collection. It:
1. Applies the final stage to the given `config` if it is a function
1. Elaborates `localSystem` and `crossSystem` with defaults as needed.
2. Infers an appropriate `platform` based on the `system` if none is
provided
2. Applies the final stage to the given `config` if it is a function
3. Defaults to no non-standard config and no cross-compilation target
@ -50,6 +49,14 @@ let # Rename the function arguments
in let
lib = import ../../lib;
localSystem = lib.systems.elaborate args.localSystem;
# Condition preserves sharing which in turn affects equality.
crossSystem =
if crossSystem0 == null || crossSystem0 == args.localSystem
then localSystem
else lib.systems.elaborate crossSystem0;
# Allow both:
# { /* the config */ } and
# { pkgs, ... } : { /* the config */ }
@ -58,17 +65,6 @@ in let
then config0 { inherit pkgs; }
else config0;
# From a minimum of `system` or `config` (actually a target triple, *not*
# nixpkgs configuration), infer the other one and platform as needed.
localSystem = lib.systems.elaborate (if builtins.isAttrs args.localSystem then (
# Allow setting the platform in the config file. This take precedence over
# the inferred platform, but not over an explicitly passed-in one.
builtins.intersectAttrs { platform = null; } config1
// args.localSystem) else args.localSystem);
crossSystem = if crossSystem0 == null then localSystem
else lib.systems.elaborate crossSystem0;
configEval = lib.evalModules {
modules = [
./config.nix

View file

@ -12,17 +12,15 @@ let
in
{ # We combine legacy `system` and `platform` into `localSystem`, if
# `localSystem` was not passed. Strictly speaking, this is pure desugar, but
# it is most convient to do so before the impure `localSystem.system` default,
# so we do it now.
localSystem ? builtins.intersectAttrs { system = null; platform = null; } args
{ # We put legacy `system` into `localSystem`, if `localSystem` was not passed.
# If neither is passed, assume we are building packages on the current
# (build, in GNU Autotools parlance) platform.
localSystem ? { system = args.system or builtins.currentSystem; }
, # These are needed only because nix's `--arg` command-line logic doesn't work
# with unnamed parameters allowed by ...
system ? localSystem.system
, platform ? localSystem.platform
, crossSystem ? null
# These are needed only because nix's `--arg` command-line logic doesn't work
# with unnamed parameters allowed by ...
, system ? localSystem.system
, crossSystem ? localSystem
, # Fallback: The contents of the configuration file found at $NIXPKGS_CONFIG or
# $HOME/.config/nixpkgs/config.nix.
@ -77,15 +75,11 @@ in
, ...
} @ args:
# If `localSystem` was explicitly passed, legacy `system` and `platform` should
# not be passed.
assert args ? localSystem -> !(args ? system || args ? platform);
# If `localSystem` was explicitly passed, legacy `system` should
# not be passed, and vice-versa.
assert args ? localSystem -> !(args ? system);
assert args ? system -> !(args ? localSystem);
import ./. (builtins.removeAttrs args [ "system" "platform" ] // {
inherit config overlays crossSystem crossOverlays;
# Fallback: Assume we are building packages on the current (build, in GNU
# Autotools parlance) system.
localSystem = if builtins.isString localSystem then localSystem
else (if args ? localSystem then {}
else { system = builtins.currentSystem; }) // localSystem;
import ./. (builtins.removeAttrs args [ "system" ] // {
inherit config overlays localSystem;
})