Merge verified Odysseus fixes

tests/test_compare_routes_shim.py

@@ -0,0 +1,25 @@
+"""Regression test for the compare route shim (slice 2i, #4082/#4071).
+
+The backward-compat shim at ``routes/compare_routes.py`` uses ``sys.modules``
+replacement so the legacy import path and the canonical ``routes.compare.*``
+path resolve to the *same* module object. This is required because
+``test_endpoint_owner_scope_followup.py`` uses ``import routes.compare_routes
+as cr`` followed by ``monkeypatch.setattr(cr, "SessionLocal", ...)`` /
+``"_owned_endpoint_by_url"`` / ``"_owned_endpoint_by_id"`` — for those patches
+to take effect at runtime, the legacy module object and the canonical one
+must be identical.
+"""
+
+import importlib
+
+import routes.compare_routes as _shim_compare  # noqa: F401
+
+
+def test_legacy_and_canonical_compare_module_are_same_object():
+    """``import routes.compare_routes`` must alias the canonical module."""
+    legacy = importlib.import_module("routes.compare_routes")
+    canonical = importlib.import_module("routes.compare.compare_routes")
+    assert legacy is canonical, (
+        "routes.compare_routes shim must resolve to the canonical "
+        "routes.compare.compare_routes module object"
+    )