coqPackages_8_20: fix sort instability - #418946
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Without the change `builtins.sort` is not guaranteed to produce stable results across `nix` implementations or even `std::sort` implementations. With a small patch from NixOS/nix#12106 (comment) `nix` shows predicate instability as: $ nix eval --impure --expr 'with import ./. {}; coqPackages_8_20' --show-trace error: … while evaluating the attribute 'coqPackages_8_20' ... … while calling the 'sort' builtin at pkgs/development/coq-modules/metacoq/default.nix:13:48: 12| owner = "MetaCoq"; 13| defaultVersion = lib.switch coq.coq-version (lib.lists.sort (x: y: lib.versions.isLe x.out y.out) ( | ^ 14| lib.mapAttrsToList (out: case: { inherit case out; }) { error: !(a < a) assert failed The fix is to use strict `<` comparison rather than non-strict `<=` one.
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The issue is rather theoretical since comparison keys come from an attrset, hence are all distinct, but why not. |
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Without the change
builtins.sortis not guaranteed to produce stable results acrossniximplementations or evenstd::sortimplementations.With a small patch from NixOS/nix#12106 (comment)
nixshows predicate instability as:The fix is to use strict
<comparison rather than non-strict<=one.Things done
nix.conf? (See Nix manual)sandbox = relaxedsandbox = truenix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage./result/bin/)Add a 👍 reaction to pull requests you find important.