From 90e7699ad7a28ffc8dbe253a2cecac5c8438bb16 Mon Sep 17 00:00:00 2001
From: Profpatsch <mail@profpatsch.de>
Date: Wed, 9 Nov 2022 10:43:31 +0100
Subject: [PATCH] nix: revive nix_2_6

The critical regression bug in
https://github.com/NixOS/nix/issues/6572 does not appear (at least as
often) in nix 2.6 according to the discussion there, so we need to
allow people to pin this older version.

Partial revert of
https://github.com/NixOS/nixpkgs/commit/b2eea05b06baa2886039d61485d37c338ad3d578
---
 pkgs/tools/package-management/nix/default.nix | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/pkgs/tools/package-management/nix/default.nix b/pkgs/tools/package-management/nix/default.nix
index 46f92a468815..6295449c7f9b 100644
--- a/pkgs/tools/package-management/nix/default.nix
+++ b/pkgs/tools/package-management/nix/default.nix
@@ -50,7 +50,13 @@ in lib.makeExtensible (self: {
 
   nix_2_5 = throw "nixVersions.nix_2_5 has been removed";
 
-  nix_2_6 = throw "nixVersions.nix_2_6 has been removed";
+  # This is the last version of nix where https://github.com/NixOS/nix/issues/6572
+  # is not an unsolved breaking bug. Please keep it until the issue is fixed
+  # and in latest stable nix.
+  nix_2_6 = common {
+    version = "2.6.1";
+    sha256 = "sha256-E9iQ7f+9Z6xFcUvvfksTEfn8LsDfzmwrcRBC//5B3V0=";
+  };
 
   nix_2_7 = common {
     version = "2.7.0";