Hypothesis ignores max_items and min_items for conlist

[mdavis-xyz]

Checks

• I added a descriptive title to this issue
• I have searched (google, github) for similar issues and couldn't find anything
• I have read and followed the docs and still think this is a bug

debug info

Output of python -c "import pydantic.utils; print(pydantic.utils.version_info())":

             pydantic version: 1.8.2
            pydantic compiled: False
                 install path: /home/ec2-user/environment/scratch/pydantic/pydantic/pydantic
               python version: 3.8.7 (default, Jun  2 2021, 12:58:26)  [GCC 7.3.1 20180712 (Red Hat 7.3.1-12)]
                     platform: Linux-4.14.232-176.381.amzn2.x86_64-x86_64-with-glibc2.26
     optional deps. installed: ['devtools', 'dotenv', 'email-validator', 'typing-extensions']

MWE

import typing
from hypothesis import given, strategies as st
from pydantic import BaseModel, conlist

class Model(BaseModel):
    x: conlist(int, min_items=1)
    
@given(st.builds(Model))
def test_property(instance):
    assert isinstance(instance, Model)
    assert len(instance.x) >= 1
    
test_property()

The expected behavior is that the script passes. Hypothesis does not generate an empty list.

Actual behavior is that hypothesis generates an empty list.

Traceback (most recent call last):
  File "mwe.py", line 13, in <module>
    test_property()
  File "mwe.py", line 10, in test_property
    def test_property(instance):
  File "/home/ec2-user/.local/lib/python3.8/site-packages/hypothesis/core.py", line 1169, in wrapped_test
    raise the_error_hypothesis_found
  File "pydantic/main.py", line 400, in pydantic.main.BaseModel.__init__
pydantic.error_wrappers.ValidationError: 1 validation error for Model
x
  ensure this value has at least 1 items (type=value_error.list.min_items; limit_value=1)

This issue is similar to #2473

Solution

A fix would look similar to #2442

[lig]

@mdavis-xyz thank you for the bug report. Could you please confirm that the bug is still relevant in Pydantic v2?

[sydney-runkle]

We’re no longer actively developing Pydantic V1 (although it will continue to receive security fixes for the next year or so), so we’re closing issues solely related to V1. If you really think this shouldn’t be closed, please comment or create a new issue 🚀.