From 9806c0cd3e6e808d0cc2089020f7f80c97c96cca Mon Sep 17 00:00:00 2001
From: Thiago Kenji Okada <thiagokokada@gmail.com>
Date: Tue, 10 Jun 2025 18:32:23 +0100
Subject: [PATCH 1/3] nixos/tools: enable `system.rebuild.enableNg` by default

---
 nixos/doc/manual/release-notes/rl-2511.section.md | 2 ++
 nixos/modules/installer/tools/tools.nix           | 7 +++++++
 2 files changed, 9 insertions(+)

diff --git a/nixos/doc/manual/release-notes/rl-2511.section.md b/nixos/doc/manual/release-notes/rl-2511.section.md
index 932ff7b6d6f7..8b2cfb815780 100644
--- a/nixos/doc/manual/release-notes/rl-2511.section.md
+++ b/nixos/doc/manual/release-notes/rl-2511.section.md
@@ -4,6 +4,8 @@
 
 <!-- To avoid merge conflicts, consider adding your item at an arbitrary place in the list instead. -->
 
+- `nixos-rebuild-ng`, a full rewrite of `nixos-rebuild` in Python, is enabled by default from this release. You can disable it by setting [](#opt-system.rebuild.enableNg) to `false` in your configuration if you need, but please report any issues. It is expected that the next major version of NixOS (26.05) will remove the {option}`system.rebuild.enableNg` option.
+
 - Secure boot support can now be enabled for the Limine bootloader through {option}`boot.loader.limine.secureBoot.enable`. Bootloader install script signs the bootloader, then kernels are hashed during system rebuild and written to a config. This allows Limine to boot only the kernels installed through NixOS system.
 
 ## New Modules {#sec-release-25.11-new-modules}
diff --git a/nixos/modules/installer/tools/tools.nix b/nixos/modules/installer/tools/tools.nix
index bbbe0a7ed4a9..b45c51e98192 100644
--- a/nixos/modules/installer/tools/tools.nix
+++ b/nixos/modules/installer/tools/tools.nix
@@ -280,6 +280,7 @@ in
   };
 
   options.system.rebuild.enableNg = lib.mkEnableOption "" // {
+    default = true;
     description = ''
       Whether to use ‘nixos-rebuild-ng’ in place of ‘nixos-rebuild’, the
       Python-based re-implementation of the original in Bash.
@@ -330,6 +331,12 @@ in
   config = {
     documentation.man.man-db.skipPackages = [ nixos-version ];
 
+    warnings = lib.optional (!config.system.disableInstallerTools && !config.system.rebuild.enableNg) ''
+      The Bash implementation of nixos-rebuild will be deprecated and removed in the 26.05 release of NixOS.
+      Please migrate to the newer implementation by removing 'system.rebuild.enableNg = false' from your configuration.
+      If you are unable to migrate due to any issues with the new implementation, please create an issue and tag the maintainers of 'nixos-rebuild-ng'.
+    '';
+
     # These may be used in auxiliary scripts (ie not part of toplevel), so they are defined unconditionally.
     system.build = {
       inherit nixos-generate-config nixos-install;

From 9b50226bf5d38d50705c6ba0e48d1e2bf7cf6710 Mon Sep 17 00:00:00 2001
From: Thiago Kenji Okada <thiagokokada@gmail.com>
Date: Tue, 10 Jun 2025 18:35:06 +0100
Subject: [PATCH 2/3] nixos/tests: set `withNg = false` in
 nixos-rebuild-install-bootloader

---
 nixos/tests/all-tests.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/nixos/tests/all-tests.nix b/nixos/tests/all-tests.nix
index aedc99b1a7e4..134dc973183d 100644
--- a/nixos/tests/all-tests.nix
+++ b/nixos/tests/all-tests.nix
@@ -942,7 +942,7 @@ in
   nixos-generate-config = runTest ./nixos-generate-config.nix;
   nixos-rebuild-install-bootloader = handleTestOn [
     "x86_64-linux"
-  ] ./nixos-rebuild-install-bootloader.nix { };
+  ] ./nixos-rebuild-install-bootloader.nix { withNg = false; };
   nixos-rebuild-install-bootloader-ng = handleTestOn [
     "x86_64-linux"
   ] ./nixos-rebuild-install-bootloader.nix { withNg = true; };

From 3c0a57d172fbf5af8082054bccb0ad1b04e36ad6 Mon Sep 17 00:00:00 2001
From: Thiago Kenji Okada <thiagokokada@gmail.com>
Date: Tue, 10 Jun 2025 18:50:40 +0100
Subject: [PATCH 3/3] nixos-rebuild-ng: clean-up README.md

---
 pkgs/by-name/ni/nixos-rebuild-ng/README.md | 34 ----------------------
 1 file changed, 34 deletions(-)

diff --git a/pkgs/by-name/ni/nixos-rebuild-ng/README.md b/pkgs/by-name/ni/nixos-rebuild-ng/README.md
index 10bd1a90e9d4..bcbadeee301b 100644
--- a/pkgs/by-name/ni/nixos-rebuild-ng/README.md
+++ b/pkgs/by-name/ni/nixos-rebuild-ng/README.md
@@ -35,40 +35,6 @@ an attempt of the rewrite.
   currently depends on `jq` for JSON parsing, while Python has `json` in
   standard library
 
-## Do's and Don'ts
-
-- Do: be as much of a drop-in replacement as possible
-- Do: fix obvious bugs
-- Do: improvements that are non-breaking
-- Don't: change logic in breaking ways even if this would be an improvement
-
-## How to use
-
-If you want to use `nixos-rebuild-ng` without replacing `nixos-rebuild`, add the
-following to your NixOS configuration:
-
-```nix
-{ pkgs, ... }:
-{
-  environment.systemPackages = [ pkgs.nixos-rebuild-ng ];
-}
-```
-
-And use `nixos-rebuild-ng` instead of `nixos-rebuild`.
-
-If you want to completely replace `nixos-rebuild` with `nixos-rebuild-ng`, add
-the following to your NixOS configuration:
-
-```nix
-{ ... }:
-{
-  system.rebuild.enableNg = true;
-}
-```
-
-This will set `config.system.build.nixos-rebuild` to `nixos-rebuild-ng`, so
-all tools that expect it in that location should work.
-
 ## Development
 
 Run: