[BEAM-4036] Pickler enters infinite recursion with self-referential classes

• Type: Bug
• Status: Open
• Priority: P3
• Resolution: Unresolved
• Component/s: sdk-py-core
• Assignee: Unassigned
• Reporter: Chuan Yu Foo
• Created: 09/Apr/18 23:10
• Updated: 03/Jun/22 21:16

Description

The pickler recurses infinitely and dies with maximum recursion limit exceeded when a module contains a self-referential class (or any class which is part of a cycle).

Here's a minimal example: 

class RecursiveClass(object):
 SELF_TYPE = None

 def __init__(self, datum)
   self.datum = 'RecursiveClass:%s' % datum

RecursiveClass.SELF_TYPE = RecursiveClass

If this is in a module, then the pickler will enter the infinite recursion when trying to pickle any nested class in that module.
 

An actual example is with typing.Type, which is part of a cycle typing.Type -> type -> object -> typing.Type. If a module contains an attribute that refers to typing.Type, such as a type alias, it will trigger this bug.

Issue Links

• links to: GitHub Pull Request #5072