test(control-plane): isolate cached temporary runtime roots

tests/control_plane/canonical_authority_fixture.py

@@ -9,6 +9,7 @@
 import os
 from pathlib import Path
 import subprocess
+import tempfile
 
 
 def initialize_canonical_authority(runtime_root: Path, goal_id: str, projection: dict, *, state_path: Path, provider: str = "file") -> dict:
@@ -45,9 +46,12 @@ def initialize_canonical_authority(runtime_root: Path, goal_id: str, projection:
 def isolate_sqlite_runtime(tmp_path, monkeypatch):
     monkeypatch.setenv("NODE_OPTIONS", os.environ.get("NODE_OPTIONS", "") + " --experimental-sqlite")
     # Do not reuse an Effect runtime started by the minimum-Node CI step.
-    # Each CLI subprocess resolves its own tempfile root from this environment.
+    # CLI subprocesses resolve their root from the environment; the current
+    # process may already have cached a different root in tempfile.tempdir.
+    # Patch both for the same lifetime, restoring the cache at fixture teardown.
     for variable in ("TMPDIR", "TEMP", "TMP"):
         monkeypatch.setenv(variable, str(tmp_path))
+    monkeypatch.setattr(tempfile, "tempdir", str(tmp_path))
 
 
 def single_snapshot_page(result: dict, goal_id: str = "goal-a") -> dict:

tests/control_plane/test_canonical_authority_fixture.py

@@ -0,0 +1,39 @@
+"""Canonical CLI tests must not reuse a host's warmed Effect runtime."""
+from __future__ import annotations
+
+import subprocess
+import sys
+import tempfile
+
+import pytest
+
+from canonical_authority_fixture import isolate_sqlite_runtime
+from loopx.control_plane.effect_runtime import _runtime_dir
+
+
+@pytest.mark.parametrize("cached", [False, True])
+def test_runtime_isolation_covers_process_and_cli_temp_directories(tmp_path, monkeypatch, cached):
+    shared = tmp_path / "shared"
+    shared.mkdir()
+    monkeypatch.setattr(tempfile, "tempdir", str(shared) if cached else None)
+
+    isolate_sqlite_runtime(tmp_path, monkeypatch)
+
+    assert tempfile.gettempdir() == str(tmp_path)
+    assert _runtime_dir().parent == tmp_path
+    child_root = subprocess.check_output(
+        [sys.executable, "-c", "import tempfile; print(tempfile.gettempdir())"], text=True,
+    ).strip()
+    assert child_root == str(tmp_path)
+
+
+def test_runtime_isolation_restores_the_process_cache(tmp_path, monkeypatch):
+    shared = tmp_path / "shared"
+    monkeypatch.setattr(tempfile, "tempdir", str(shared))
+
+    with monkeypatch.context() as isolated:
+        isolate_sqlite_runtime(tmp_path, isolated)
+        assert _runtime_dir().parent == tmp_path
+
+    assert tempfile.tempdir == str(shared)
+    assert _runtime_dir().parent == shared