Merge pull request #1318 from flyingcircusio/os-python-previous-version

platform/packages: Keep around one earlier python version

Author: osnyx

changelog.d/20250303_183108_os-python-previous-version_scriv.md

@@ -0,0 +1,17 @@
+<!--
+
+A new changelog entry.
+
+Delete placeholder items that do not apply. Empty sections will be removed
+automatically during release.
+
+Leave the XX.XX as is: this is a placeholder and will be automatically filled
+correctly during the release and helps when backporting over multiple platform
+branches.
+
+-->
+
+
+### NixOS XX.XX platform
+
+- install python-3.11 by default in addition to the default python-3.12

nixos/platform/packages.nix

@@ -3,7 +3,12 @@
 {
   config = {
 
-    environment.systemPackages = with pkgs; [
+    environment.systemPackages = with pkgs;
+    let
+      previousPythonVersion = ver:
+        "${lib.versions.major ver}${toString (lib.toInt(lib.versions.minor ver) - 1)}";
+      previousPython = pkgs."python${previousPythonVersion pkgs.python3.version}";
+    in [
         apacheHttpd
         atop
         automake
@@ -52,6 +57,8 @@
         psmisc
         pwgen
         (python3.withPackages (ps: with ps; [ setuptools ]))
+        # keep around at least one previous python version for upgrade compatibility
+        (previousPython.withPackages (ps: with ps; [setuptools]))
         python3Packages.virtualenv
         rclone
         ripgrep