diff options
Diffstat (limited to 'Lib/importlib/util.py')
| -rw-r--r-- | Lib/importlib/util.py | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/Lib/importlib/util.py b/Lib/importlib/util.py index da9bd08..f1bb4b1 100644 --- a/Lib/importlib/util.py +++ b/Lib/importlib/util.py @@ -178,12 +178,11 @@ class _LazyModule(types.ModuleType): # Only the first thread to get the lock should trigger the load # and reset the module's class. The rest can now getattr(). if object.__getattribute__(self, '__class__') is _LazyModule: - # The first thread comes here multiple times as it descends the - # call stack. The first time, it sets is_loading and triggers - # exec_module(), which will access module.__dict__, module.__name__, - # and/or module.__spec__, reentering this method. These accesses - # need to be allowed to proceed without triggering the load again. - if loader_state['is_loading'] and attr.startswith('__') and attr.endswith('__'): + # Reentrant calls from the same thread must be allowed to proceed without + # triggering the load again. + # exec_module() and self-referential imports are the primary ways this can + # happen, but in any case we must return something to avoid deadlock. + if loader_state['is_loading']: return object.__getattribute__(self, attr) loader_state['is_loading'] = True |