support inner class with multiple inheritance

Summary:
Pull Request resolved: https://github.com/facebookresearch/d2go/pull/400

Before the diff, the bootstrap can't handle the following gramma:

https://www.internalfb.com/code/fbsource/[010f09214704]/fbcode/mobile-vision/d2go/tests/modeling/test_modeling_distillation.py?lines=231-236

The fix is recursively applying the truncating trick.

Reviewed By: itomatik

Differential Revision: D40701375

fbshipit-source-id: 946b6be47aa4b879e2e247b879a0d8b9ac13822b

d2go/registry/bootstrap.py

@@ -278,11 +278,15 @@ def _bootstrap_file(
         # HACK: convert multiple inheritance to single inheritance, this is needed
         # because current implementation of MoreMagicMock can't handle this well.
         # eg. `class MyClass(MyMixin, nn.Module)` -> `class MyClass(MyMixin)`
-        for stmt in tree.body:
-            if isinstance(stmt, ast.ClassDef):
-                if len(stmt.bases) > 1:
-                    stmt.bases = stmt.bases[:1]
-                stmt.keywords.clear()
+        def _truncate_multiple_inheritance(ast_tree):
+            for stmt in ast_tree.body:
+                if isinstance(stmt, ast.ClassDef):
+                    if len(stmt.bases) > 1:
+                        stmt.bases = stmt.bases[:1]
+                    stmt.keywords.clear()
+                    _truncate_multiple_inheritance(stmt)
+
+        _truncate_multiple_inheritance(tree)
 
     _log(2, f"Parsing AST takes {t.time} sec")
 

tests/skip_init/test_registries_bootstrap.py

@@ -47,10 +47,10 @@ class TestRegistryBootstrap(unittest.TestCase):
 
     def test_bootstrap_core_lib(self):
         self.assertFalse(bootstrap._IS_BOOTSTRAPPED)
-        bootstrap.bootstrap_registries(enable_cache=False, catch_exception=True)
+        bootstrap.bootstrap_registries(enable_cache=False, catch_exception=False)
         self.assertTrue(bootstrap._IS_BOOTSTRAPPED)
 
     def test_bootstrap_with_cache(self):
         self.assertFalse(bootstrap._IS_BOOTSTRAPPED)
-        bootstrap.bootstrap_registries(enable_cache=True, catch_exception=True)
+        bootstrap.bootstrap_registries(enable_cache=True, catch_exception=False)
         self.assertTrue(bootstrap._IS_BOOTSTRAPPED)