refactor: replace eval_nix/build_nix with machine.select()

- Remove nix(), eval_nix(), and build_nix() methods from Machine class
- Add select() method that handles machine-specific attribute prefixes
- Update all usages to use machine.select() directly
- Handle Path conversion and tmp_store logic at call sites
- This simplifies the Machine API and prepares for deployment.json removal

pkgs/clan-cli/clan_cli/tests/test_vars.py

@@ -992,7 +992,7 @@ def test_dynamic_invalidation(
     # before generating, dependent generator validation should be empty; see bogus hardware-configuration.nix above
     # we have to avoid `*.files.value` in this initial select because the generators haven't been run yet
     # Generators 0: The initial generators before any 'vars generate'
-    generators_0 = machine.eval_nix(f"{gen_prefix}.*.{{validationHash}}")
+    generators_0 = machine.select(f"{gen_prefix}.*.{{validationHash}}")
     assert generators_0["dependent_generator"]["validationHash"] is None
 
     # generate both my_generator and (the dependent) dependent_generator
@@ -1001,7 +1001,7 @@ def test_dynamic_invalidation(
 
     # after generating once, dependent generator validation should be set
     # Generators_1: The generators after the first 'vars generate'
-    generators_1 = machine.eval_nix(gen_prefix)
+    generators_1 = machine.select(gen_prefix)
     assert generators_1["dependent_generator"]["validationHash"] is not None
 
     # @tangential: after generating once, neither generator should want to run again because `clan vars generate` should have re-evaluated the dependent generator's validationHash after executing the parent generator but before executing the dependent generator
@@ -1014,7 +1014,7 @@ def test_dynamic_invalidation(
     cli.run(["vars", "generate", "--flake", str(flake.path), machine.name])
     clan_flake.invalidate_cache()
     # Generators_2: The generators after the second 'vars generate'
-    generators_2 = machine.eval_nix(gen_prefix)
+    generators_2 = machine.select(gen_prefix)
     assert (
         generators_1["dependent_generator"]["validationHash"]
         == generators_2["dependent_generator"]["validationHash"]

pkgs/clan-cli/clan_cli/vars/generate.py

@@ -72,14 +72,20 @@ class Generator:
 
     def final_script(self) -> Path:
         assert self._machine is not None
-        final_script = self._machine.build_nix(
-            f'config.clan.core.vars.generators."{self.name}".finalScript'
+        from clan_lib.nix import nix_test_store
+
+        output = Path(
+            self._machine.select(
+                f'config.clan.core.vars.generators."{self.name}".finalScript'
+            )
         )
-        return final_script
+        if tmp_store := nix_test_store():
+            output = tmp_store.joinpath(*output.parts[1:])
+        return output
 
     def validation(self) -> str | None:
         assert self._machine is not None
-        return self._machine.eval_nix(
+        return self._machine.select(
             f'config.clan.core.vars.generators."{self.name}".validationHash'
         )
 

pkgs/clan-cli/clan_cli/vars/secret_modules/password_store.py

@@ -33,7 +33,7 @@ class SecretStore(StoreBase):
 
     @property
     def _store_backend(self) -> str:
-        backend = self.machine.eval_nix("config.clan.core.vars.settings.passBackend")
+        backend = self.machine.select("config.clan.core.vars.settings.passBackend")
         return backend
 
     @property

pkgs/clan-cli/clan_cli/vms/inspect.py

@@ -55,7 +55,7 @@ class VmConfig:
 
 
 def inspect_vm(machine: Machine) -> VmConfig:
-    data = machine.eval_nix("config.clan.core.vm.inspect")
+    data = machine.select("config.clan.core.vm.inspect")
     # HACK!
     data["flake_url"] = dataclasses.asdict(machine.flake)
     return VmConfig.from_json(data)

pkgs/clan-cli/clan_cli/vms/run.py

@@ -49,16 +49,24 @@ def facts_to_nixos_config(facts: dict[str, dict[str, bytes]]) -> dict:
 
 
 # TODO move this to the Machines class
-def build_vm(machine: Machine, tmpdir: Path) -> dict[str, str]:
+def build_vm(
+    machine: Machine, tmpdir: Path, nix_options: list[str] | None = None
+) -> dict[str, str]:
     # TODO pass prompt here for the GTK gui
-
+    if nix_options is None:
+        nix_options = []
     secrets_dir = get_secrets(machine, tmpdir)
 
-    public_facts = machine.public_facts_store.get_all()
+    from clan_lib.nix import nix_test_store
 
-    nixos_config_file = machine.build_nix(
-        "config.system.clan.vm.create", extra_config=facts_to_nixos_config(public_facts)
+    output = Path(
+        machine.select(
+            "config.system.clan.vm.create",
+        )
     )
+    if tmp_store := nix_test_store():
+        output = tmp_store.joinpath(*output.parts[1:])
+    nixos_config_file = output
     try:
         vm_data = json.loads(Path(nixos_config_file).read_text())
         vm_data["secrets_dir"] = str(secrets_dir)