Merge pull request 'vars/list: reduce cache misses to 1' (#5331) from dave into main

Reviewed-on: https://git.clan.lol/clan/clan-core/pulls/5331

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

@@ -1263,6 +1263,41 @@ def test_share_mode_switch_regenerates_secret(
     )
 
 
+@pytest.mark.with_core
+def test_cache_misses_for_vars_list(
+    monkeypatch: pytest.MonkeyPatch,
+    flake: ClanFlake,
+) -> None:
+    """Test that listing vars results in exactly one cache miss."""
+    config = flake.machines["my_machine"]
+    config["nixpkgs"]["hostPlatform"] = "x86_64-linux"
+
+    # Set up a simple generator
+    my_generator = config["clan"]["core"]["vars"]["generators"]["my_generator"]
+    my_generator["files"]["my_value"]["secret"] = False
+    my_generator["script"] = 'echo -n "test" > "$out"/my_value'
+
+    flake.refresh()
+    monkeypatch.chdir(flake.path)
+
+    # # Generate the vars first
+    # cli.run(["vars", "generate", "--flake", str(flake.path), "my_machine"])
+
+    # Create a fresh machine object to ensure clean cache state
+    machine = Machine(name="my_machine", flake=Flake(str(flake.path)))
+
+    # Record initial cache misses
+    initial_cache_misses = machine.flake._cache_misses
+
+    # List all vars - this should result in exactly one cache miss
+    stringify_all_vars(machine)
+
+    # Assert we had exactly one cache miss for the efficient lookup
+    assert machine.flake._cache_misses == initial_cache_misses + 1, (
+        f"Expected exactly 1 cache miss for vars list, got {machine.flake._cache_misses - initial_cache_misses}"
+    )
+
+
 @pytest.mark.with_core
 def test_dynamic_invalidation(
     monkeypatch: pytest.MonkeyPatch,

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

@@ -23,8 +23,6 @@ def get_machine_vars(machine: Machine) -> list[Var]:
     """
     # TODO: We dont have machine level store / this granularity yet
     # We should move the store definition to the flake, as there can be only one store per clan
-    pub_store = machine.public_vars_store
-    sec_store = machine.secret_vars_store
 
     all_vars = []
 
@@ -34,9 +32,9 @@ def get_machine_vars(machine: Machine) -> list[Var]:
     for generator in generators:
         for var in generator.files:
             if var.secret:
-                var.store(sec_store)
+                var.store(machine.secret_vars_store)
             else:
-                var.store(pub_store)
+                var.store(machine.public_vars_store)
             var.generator(generator)
             all_vars.append(var)
     return all_vars

pkgs/clan-cli/clan_lib/flake/flake.py

@@ -792,6 +792,7 @@ class Flake:
     _cache: FlakeCache | None = field(init=False, default=None)
     _path: Path | None = field(init=False, default=None)
     _is_local: bool | None = field(init=False, default=None)
+    _cache_misses: int = field(init=False, default=0)
 
     @classmethod
     def from_json(
@@ -1062,6 +1063,8 @@ class Flake:
         ]
 
         if not_fetched_selectors:
+            # Increment cache miss counter for each selector that wasn't cached
+            self._cache_misses += 1
             self.get_from_nix(not_fetched_selectors)
 
     def select(
@@ -1087,6 +1090,7 @@ class Flake:
         if not self._cache.is_cached(selector):
             log.debug(f"(cached) $ clan select {shlex.quote(selector)}")
             log.debug(f"Cache miss for {selector}")
+            self._cache_misses += 1
             self.get_from_nix([selector])
         else:
             log.debug(f"$ clan select {shlex.quote(selector)}")