From 96144fde81e63b2c05dce2ced8f30cdac585ea2f Mon Sep 17 00:00:00 2001
From: Erik Arvstedt <erik.arvstedt@gmail.com>
Date: Mon, 27 Jun 2022 20:45:10 +0200
Subject: [PATCH] update-flake.nix: fix stable pkgs selection

In rare cases, the nixpkgs stable version of a package can be newer
than in unstable nixpkgs. [1]
When this happens, choose the newer stable version instead of the
older unstable version.

[1] E.g., when a package is updated in both nixpkgs stable and unstable,
and nixpkgs stable is released before unstable.
---
 helper/update-flake.nix | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/helper/update-flake.nix b/helper/update-flake.nix
index 43fbd9c..2bc592e 100644
--- a/helper/update-flake.nix
+++ b/helper/update-flake.nix
@@ -8,8 +8,8 @@ in rec {
   #   stable = { bitcoind = "0.21.1"; ... };
   #   unstable = { btcpayserver = "1.2.1"; ... };
   # }
-  # A pinned pkg is added to `stable` if the stable and unstable pkg versions
-  # are identical.
+  # A pinned pkg is added to `stable` if its stable version is newer or
+  # identical to the unstable version.
   versions = let
     pinned = flake.legacyPackages.x86_64-linux.pinned;
     pinnedPkgs = lib.filterAttrs (n: v: lib.isDerivation v) pinned;
@@ -17,7 +17,8 @@ in rec {
     unstable = pinned.pkgsUnstable;
     isStable = builtins.partition (pkgName:
       !(unstable ? "${pkgName}") ||
-      ((stable ? "${pkgName}") && stable.${pkgName}.version == unstable.${pkgName}.version)
+      ((stable ? "${pkgName}")
+       && (builtins.compareVersions stable.${pkgName}.version unstable.${pkgName}.version >= 0))
     ) (builtins.attrNames pinnedPkgs);
   in {
     stable   = lib.genAttrs isStable.right (pkgName: stable.${pkgName}.version);