From ef6ac2dd6e6fe0f800d008fd9e314226617fb96a Mon Sep 17 00:00:00 2001
From: Sergei Trofimovich <slyich@gmail.com>
Date: Thu, 26 Dec 2024 23:00:05 +0000
Subject: [PATCH] coqPackages.metaFetch: fix `sort` predicate stability

Incorrect sorting predicate was found as part of
https://github.com/NixOS/nix/issues/12106 where `nix` was crashing on
the code like:

    $ nix eval --expr 'builtins.sort (a: b: true) [ 1 2 3 ]'
    ...
    Aborted (core dumped)

Note: the crash happens here because sorting predicate does not
implement `lessThan` and triggers assertion failures for
`std::stable_sort` that backs `builtins.sort`.

The change restores `lessThan` semantic for `version sorting`.
---
 pkgs/build-support/coq/meta-fetch/default.nix | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pkgs/build-support/coq/meta-fetch/default.nix b/pkgs/build-support/coq/meta-fetch/default.nix
index 7491d0205c251..cc435b299cfd6 100644
--- a/pkgs/build-support/coq/meta-fetch/default.nix
+++ b/pkgs/build-support/coq/meta-fetch/default.nix
@@ -27,7 +27,7 @@ let
     sort
     switch
     switch-if
-    versionAtLeast
+    versionOlder
     versions
     ;
 
@@ -112,7 +112,7 @@ let
   shortVersion =
     x:
     if (isString x && match "^/.*" x == null) then
-      findFirst (v: versions.majorMinor v == x) null (sort versionAtLeast (attrNames release))
+      findFirst (v: versions.majorMinor v == x) null (sort (l: r: versionOlder r l) (attrNames release))
     else
       null;
   isShortVersion = x: shortVersion x != null;