test(pm): exercise active profile propagation through real subprocess env

pm/plugins_state.py

@@ -85,12 +85,8 @@ def enabled_plugins_ordered(*, proposed_home=None, enabled=None, disabled=None)
     The ACTIVE MEMORY PROVIDER joins its home's list: providers install
     via ``memory.provider`` (mnemosyne's documented path), not via
     plugins.enabled — without this, a provider's dep plugin never joins
-    the union. GAP, stated honestly: pm has NO automatic bisect or
-    disable decision today — a resolver conflict fails loud and the
-    admission authority refuses the candidate; nothing disables plugins
-    on its own, so "prefer the memory provider" is not yet implemented
-    by any code path. When such a decision exists it must keep the
-    active memory provider over ordinary plugins."""
+    the union. Admission refuses a conflicting candidate without changing
+    the active environment or disabling an existing provider."""
     out: dict[Path, list[str]] = {}
     for home in _all_homes():
         # ONE parse per home feeds both queries (enabled + provider).

tests/pm/test_plugin_survival_contract.py

@@ -266,31 +266,20 @@ def test_retry_after_conflict_enables_resolvable_candidate(admission_env):
 # 4. Active context home propagates to wrapper subprocess launches
 # ---------------------------------------------------------------------------
 
-@pytest.mark.skipif(sys.platform != "win32", reason="detached respawn spec is Windows")
 def test_active_context_home_exported_to_wrapper_subprocess(monkeypatch, tmp_path):
-    """Hermes subprocess launchers must pass HERMES_HOME explicitly (the
-    context-local override never crosses a process boundary on its own).
-    The detached respawn spec exports the ACTIVE context home, and a
-    child launched with that overlay observes it."""
     from hermes_constants import reset_hermes_home_override, set_hermes_home_override
-    from hermes_cli.gateway_windows import windowless_gateway_restart_spec
+    from tools.environments.local import build_subprocess_env
 
-    active = tmp_path / "profiles" / "worker"
+    monkeypatch.setenv("HERMES_HOME", str(tmp_path / "ambient"))
+    active = tmp_path / "custom-root/profiles/worker"
     active.mkdir(parents=True)
     token = set_hermes_home_override(active)
     try:
-        argv, _cwd, overlay = windowless_gateway_restart_spec([sys.executable, "-c", "pass"])
-        assert overlay.get("HERMES_HOME") == str(active), (
-            "the respawn overlay must export the ACTIVE context home as HERMES_HOME"
+        child_env = build_subprocess_env()
+        child = subprocess.run(
+            [sys.executable, "-c", "import os; print(os.environ['HERMES_HOME'], end='')"],
+            env=child_env, capture_output=True, text=True, check=True, timeout=60,
         )
+        assert child.stdout == str(active)
     finally:
         reset_hermes_home_override(token)
-
-    # and a real subprocess launched with that overlay sees it
-    child_env = {**os.environ, **overlay}
-    out = subprocess.run(
-        [sys.executable, "-c",
-         "import os; print(os.environ['HERMES_HOME'], end='')"],
-        env=child_env, capture_output=True, text=True, timeout=60,
-    )
-    assert out.returncode == 0 and out.stdout == str(active)