feat: track Decman configuration

system-config/scripts/verify.py

@@ -0,0 +1,92 @@
+#!/usr/bin/env python3
+"""Read-only invariant checks for the active Decman configuration."""
+
+from __future__ import annotations
+
+import os
+import runpy
+import subprocess
+import sys
+from collections import Counter
+from collections.abc import Callable
+from pathlib import Path
+from typing import cast
+
+ROOT = Path(__file__).resolve().parents[1]
+PACKAGES = ROOT / "packages"
+
+
+def lines(path: Path) -> set[str]:
+    return {
+        line.strip()
+        for line in path.read_text(encoding="utf-8").splitlines()
+        if line.strip()
+    }
+
+
+def actual(command: str) -> set[str]:
+    return set(
+        subprocess.run(
+            ["pacman", command], check=True, text=True, stdout=subprocess.PIPE
+        ).stdout.split()
+    )
+
+
+def main() -> None:
+    repo_files = list(PACKAGES.glob("**/*-repo.txt"))
+    aur_files = list(PACKAGES.glob("**/*-aur.txt"))
+    repo = [name for path in repo_files for name in lines(path)]
+    aur = [name for path in aur_files for name in lines(path)]
+    duplicate = {name for name, count in Counter(repo + aur).items() if count > 1}
+    if duplicate:
+        raise SystemExit(f"duplicate package ownership: {sorted(duplicate)}")
+    installed_repo = actual("-Qqen")
+    installed_aur = actual("-Qqem")
+
+    os.chdir(ROOT)
+    sys.path.insert(0, str(ROOT))
+    import decman
+
+    runpy.run_path(str(ROOT / "source.py"))
+    loaded_repo: set[str] = set()
+    loaded_aur: set[str] = set()
+    for module in decman.modules:
+        native = getattr(module, "native_packages", None)
+        foreign = getattr(module, "aur_packages", None)
+        if callable(native):
+            loaded_repo |= cast(Callable[[], set[str]], native)()
+        if callable(foreign):
+            loaded_aur |= cast(Callable[[], set[str]], foreign)()
+    if loaded_repo != set(repo) or loaded_aur != set(aur):
+        raise SystemExit("active profile does not compose the full laptop package set")
+    expected_system = set().union(
+        *(lines(path) for path in (ROOT / "manifests").glob("**/*-system.txt"))
+    )
+    expected_user = set().union(
+        *(lines(path) for path in (ROOT / "manifests").glob("**/*-user.txt"))
+    )
+    loaded_system: set[str] = set()
+    loaded_user: set[str] = set()
+    for module in decman.modules:
+        system = getattr(module, "system_units", None)
+        user = getattr(module, "user_units", None)
+        if callable(system):
+            loaded_system |= cast(Callable[[], set[str]], system)()
+        if callable(user):
+            loaded_user |= cast(Callable[[], dict[str, set[str]]], user)().get(
+                "alex", set()
+            )
+    if loaded_system != expected_system or loaded_user != expected_user:
+        raise SystemExit("active profile does not compose the complete unit manifests")
+    pending_remove = sorted((installed_repo - set(repo)) | (installed_aur - set(aur)))
+    pending_install = sorted((set(repo) - installed_repo) | (set(aur) - installed_aur))
+    print(
+        f"OK: repo={len(repo)} aur={len(aur)} system={len(loaded_system)} "
+        f"user={len(loaded_user)} concerns={len(repo_files)} profile=laptop"
+    )
+    print(f"PENDING REMOVE: {' '.join(pending_remove) or 'none'}")
+    print(f"PENDING INSTALL: {' '.join(pending_install) or 'none'}")
+
+
+if __name__ == "__main__":
+    main()