Multiple RecursionErrors with self-referencing models #524
Description
- OS: Ubuntu 19.04
- Python version: 3.7.3 (default, Apr 3 2019, 05:39:12) [GCC 8.3.0]
- Pydantic version: 0.25
The following code works:
from typing import Optional
from pydantic import BaseModel
class Foo(BaseModel):
id: str
parent: Optional['Foo'] = None
child: Optional['Foo'] = None
# 1:
# class Config:
# validate_assignment = True
def __contains__(self, other):
return other is self or other in self.child
Foo.update_forward_refs()
items = []
for i in range(10):
items.append(Foo(id='Object {}'.format(i)))
if i > 0:
# 2:
# print(items[-1], items[-2])
items[-1].parent = items[-2]
items[-2].child = items[-1]
print(items[1] in items[0])
print(items[-1] in items[0])However, RecursionError can be triggered in two trivial ways:
Uncommenting the lines at # 1: which set validate_assignment = True:
File "/home/khaeru/.local/lib/python3.7/site-packages/pydantic/main.py", line 473, in _iter
yield k, self._get_value(v, by_alias=by_alias, skip_defaults=skip_defaults)
File "/home/khaeru/.local/lib/python3.7/site-packages/pydantic/main.py", line 443, in _get_value
return v.dict(by_alias=by_alias, skip_defaults=skip_defaults)
File "/home/khaeru/.local/lib/python3.7/site-packages/pydantic/main.py", line 284, in dict
return {get_key(k): v for k, v in self._iter(by_alias=by_alias, skip_defaults=skip_defaults)}
File "/home/khaeru/.local/lib/python3.7/site-packages/pydantic/main.py", line 284, in <dictcomp>
return {get_key(k): v for k, v in self._iter(by_alias=by_alias, skip_defaults=skip_defaults)}
File "/home/khaeru/.local/lib/python3.7/site-packages/pydantic/main.py", line 473, in _iter
yield k, self._get_value(v, by_alias=by_alias, skip_defaults=skip_defaults)
File "/home/khaeru/.local/lib/python3.7/site-packages/pydantic/main.py", line 442, in _get_value
if isinstance(v, BaseModel):
File "/usr/lib/python3.7/abc.py", line 139, in __instancecheck__
return _abc_instancecheck(cls, instance)
RecursionError: maximum recursion depth exceeded in comparison
Uncommenting the line at # 2: with the print(...) call:
File "/home/khaeru/.local/lib/python3.7/site-packages/pydantic/utils.py", line 144, in truncate
v = repr(v)
File "/home/khaeru/.local/lib/python3.7/site-packages/pydantic/main.py", line 502, in __repr__
return f'<{self}>'
File "/home/khaeru/.local/lib/python3.7/site-packages/pydantic/main.py", line 513, in __str__
return self.to_string()
File "/home/khaeru/.local/lib/python3.7/site-packages/pydantic/main.py", line 509, in to_string
divider.join('{}={}'.format(k, truncate(v)) for k, v in self.__values__.items()),
File "/home/khaeru/.local/lib/python3.7/site-packages/pydantic/main.py", line 509, in <genexpr>
divider.join('{}={}'.format(k, truncate(v)) for k, v in self.__values__.items()),
File "/home/khaeru/.local/lib/python3.7/site-packages/pydantic/utils.py", line 144, in truncate
v = repr(v)
RecursionError: maximum recursion depth exceeded