test: invert UI boundary guard to allowlist

Co-authored-by: Copilot App <[email protected]>

tests/test_ui_boundaries.py

@@ -15,23 +15,15 @@ UI_DIR = Path(__file__).resolve().parents[1] / "src" / "transcription" / "ui"
 PAGES_DIR = UI_DIR / "pages"
 COMPONENTS_DIR = UI_DIR / "components"
 
-# Names a page must not pull in: they hand the page a session, a transaction, ORM
-# loader introspection, or process-global configuration.
-FORBIDDEN_PAGE_IMPORTS = frozenset(
-    {
-        "session_scope",
-        "transaction_scope",
-        "get_session_factory",
-        "resolve_session_factory",
-        "get_settings",
-        "get_engine",
-        "upgrade_schema",
-        "create_all",
-    }
-)
-
 FORBIDDEN_PAGE_MODULES = frozenset({"sqlalchemy", "sqlmodel"})
 
+# Sensitive modules are allowlisted, not blocklisted, so newly added persistence
+# helpers cannot slip through by using an unlisted name.
+PAGE_IMPORT_ALLOWLIST: dict[tuple[str, int], frozenset[str]] = {
+    ("db.session", 3): frozenset({"SessionFactoryDep"}),
+    ("transcription.config", 0): frozenset({"Settings"}),
+}
+
 
 def _page_paths() -> list[Path]:
     return sorted(path for path in PAGES_DIR.glob("*.py") if path.stem != "__init__")
@@ -57,6 +49,21 @@ def _imports(tree: ast.Module) -> tuple[set[str], set[str]]:
     return names, modules
 
 
+def _page_allowlist_violations(tree: ast.Module) -> set[str]:
+    violations: set[str] = set()
+    for node in ast.walk(tree):
+        if not isinstance(node, ast.ImportFrom) or not node.module:
+            continue
+        allowed = PAGE_IMPORT_ALLOWLIST.get((node.module, node.level))
+        if allowed is None:
+            continue
+        for alias in node.names:
+            imported_name = alias.name
+            if imported_name not in allowed:
+                violations.add(f"{'.' * node.level}{node.module}.{imported_name}")
+    return violations
+
+
 def test_page_modules_are_discovered():
     """Guard the guard: the rules below are meaningless if nothing is scanned."""
     discovered = {path.stem for path in _page_paths()}
@@ -67,8 +74,10 @@ def test_no_page_imports_persistence_or_process_globals():
     """HIGH-07: pages orchestrate services; they do not own sessions or settings."""
     violations: dict[str, list[str]] = {}
     for path in _page_paths():
-        names, modules = _imports(ast.parse(path.read_text(encoding="utf-8")))
+        tree = ast.parse(path.read_text(encoding="utf-8"))
-        found = sorted((names & FORBIDDEN_PAGE_IMPORTS) | (modules & FORBIDDEN_PAGE_MODULES))
+        _, modules = _imports(tree)
+        allowlist_violations = _page_allowlist_violations(tree)
+        found = sorted((modules & FORBIDDEN_PAGE_MODULES) | allowlist_violations)
         if found:
             violations[path.stem] = found
     assert violations == {}
@@ -79,7 +88,8 @@ def test_no_component_resolves_request_or_application_state():
     violations: dict[str, list[str]] = {}
     for path in _component_paths():
         names, modules = _imports(ast.parse(path.read_text(encoding="utf-8")))
-        found = sorted((names & FORBIDDEN_PAGE_IMPORTS) | (modules & (FORBIDDEN_PAGE_MODULES | {"fastapi"})))
+        forbidden_names = {"get_settings", "get_engine", "session_scope", "transaction_scope"}
+        found = sorted((names & forbidden_names) | (modules & (FORBIDDEN_PAGE_MODULES | {"fastapi"})))
         if found:
             violations[str(path.relative_to(COMPONENTS_DIR))] = found
     assert violations == {}