From dff88cbd79ddd9d0ba9f5b3b81d257d16e62ebc9 Mon Sep 17 00:00:00 2001
From: r-vdp <ramses@well-founded.dev>
Date: Tue, 9 Jun 2026 22:03:02 +0300
Subject: [PATCH] nixos/systemd-boot: drop bootspec synthesize fallback

Older generations without boot.json are skipped with a
warning.
---
 .../systemd-boot/systemd-boot-builder.py      | 44 +++++++++----------
 .../boot/loader/systemd-boot/systemd-boot.nix |  2 -
 nixos/tests/installer.nix                     |  1 -
 3 files changed, 20 insertions(+), 27 deletions(-)

diff --git a/nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py b/nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py
index a0d4256c3c0f..06c15ee6674b 100644
--- a/nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py
+++ b/nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py
@@ -27,7 +27,6 @@ NIXOS_DIR = Path(
 TIMEOUT = "@timeout@"
 EDITOR = "@editor@" == "1"  # noqa: PLR0133
 CONSOLE_MODE = "@consoleMode@"
-BOOTSPEC_TOOLS = "@bootspecTools@"
 DISTRO_NAME = "@distroName@"
 NIX = "@nix@"
 SYSTEMD = "@systemd@"
@@ -291,31 +290,26 @@ def write_loader_conf(default_entry_id: str | None) -> None:
     os.rename(tmp, LOADER_CONF)
 
 
-def get_bootspec(profile: str | None, generation: int) -> BootSpec:
+def get_bootspec(profile: str | None, generation: int) -> BootSpec | None:
     system_directory = system_dir(profile, generation, None)
     boot_json_path = (system_directory / "boot.json").resolve()
-    if boot_json_path.is_file():
-        with boot_json_path.open("r") as f:
-            # check if json is well-formed, else throw error with filepath
-            try:
-                bootspec_json = json.load(f)
-            except ValueError as e:
-                print(
-                    f"error: Malformed Json: {e}, in {boot_json_path}", file=sys.stderr
-                )
-                sys.exit(1)
-    else:
-        boot_json_str = run(
-            [
-                f"{BOOTSPEC_TOOLS}/bin/synthesize",
-                "--version",
-                "1",
-                system_directory,
-                "/dev/stdout",
-            ],
-            stdout=subprocess.PIPE,
-        ).stdout
-        bootspec_json = json.loads(boot_json_str)
+    if not boot_json_path.is_file():
+        print(
+            f"warning: skipping generation {generation}"
+            + (f" of profile {profile}" if profile else "")
+            + f": {boot_json_path} does not exist",
+            file=sys.stderr,
+        )
+        return None
+    with boot_json_path.open("r") as f:
+        # check if json is well-formed, else throw error with filepath
+        try:
+            bootspec_json = json.load(f)
+        except ValueError as e:
+            print(
+                f"error: Malformed Json: {e}, in {boot_json_path}", file=sys.stderr
+            )
+            sys.exit(1)
     return bootspec_from_json(bootspec_json)
 
 
@@ -551,6 +545,8 @@ def install_bootloader(args: argparse.Namespace) -> None:
 
     for gen in gens:
         bootspec = get_bootspec(gen.profile, gen.generation)
+        if bootspec is None:
+            continue
         is_default = Path(bootspec.init).parent == default_config
         new_boot_files, new_bootctl_id = boot_file(*gen, machine_id, bootspec)
         boot_files.extend(new_boot_files)
diff --git a/nixos/modules/system/boot/loader/systemd-boot/systemd-boot.nix b/nixos/modules/system/boot/loader/systemd-boot/systemd-boot.nix
index 4c3c28b11e90..31590bb1101b 100644
--- a/nixos/modules/system/boot/loader/systemd-boot/systemd-boot.nix
+++ b/nixos/modules/system/boot/loader/systemd-boot/systemd-boot.nix
@@ -47,8 +47,6 @@ let
 
       systemd = config.systemd.package;
 
-      bootspecTools = config.boot.bootspec.package;
-
       nix = config.nix.package.out;
 
       timeout = if config.boot.loader.timeout == null then "menu-force" else config.boot.loader.timeout;
diff --git a/nixos/tests/installer.nix b/nixos/tests/installer.nix
index b8f2fad73503..76b3b62c0389 100644
--- a/nixos/tests/installer.nix
+++ b/nixos/tests/installer.nix
@@ -793,7 +793,6 @@ let
                 ++ optionals (bootLoader == "systemd-boot") [
                   pkgs.zstd.bin
                   pkgs.mypy
-                  config.boot.bootspec.package
                 ]
                 ++ optionals clevisTest [ pkgs.klibc ]
                 ++ optional systemdStage1 config.system.nixos-init.package;