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Diffstat (limited to 'lib/sqlalchemy/ext/declarative/clsregistry.py')
| -rw-r--r-- | lib/sqlalchemy/ext/declarative/clsregistry.py | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/lib/sqlalchemy/ext/declarative/clsregistry.py b/lib/sqlalchemy/ext/declarative/clsregistry.py index 4595b857a..3ef63a5ae 100644 --- a/lib/sqlalchemy/ext/declarative/clsregistry.py +++ b/lib/sqlalchemy/ext/declarative/clsregistry.py @@ -103,7 +103,12 @@ class _MultipleClassMarker(object): self.on_remove() def add_item(self, item): - modules = set([cls().__module__ for cls in self.contents]) + # protect against class registration race condition against + # asynchronous garbage collection calling _remove_item, + # [ticket:3208] + modules = set([ + cls.__module__ for cls in + [ref() for ref in self.contents] if cls is not None]) if item.__module__ in modules: util.warn( "This declarative base already contains a class with the " |