Regression in ByteSize error after migrating to pydantic 2.6

[mardiros]

Initial Checks

• I confirm that I'm using Pydantic V2

Description

Hi, I prefer to starts by a small thank you for your work, you did an amazing job with this library.

Here is a detailed description of the issue.

validation errors regression

In pydantic 2.6, for some reason the 'loc' of errors is now ('byte_size', 'constrained-str')
and not ('byte_size') for the ByteSize type. The error msg is also not clean.

The example works on pydantic 3.5.3 but failed with pydantic 2.6.0

Migrate to pydantic 2.6

$ poetry install

Package operations: 0 installs, 2 updates, 0 removals

  • Updating pydantic-core (2.14.6 -> 2.16.1)
  • Updating pydantic (2.5.3 -> 2.6.0)

[...]

Tests Results:

tests/helpers/test_pydantic_2_6_migration.py::test_bytes_errors_format[invalid unit] PASSED
tests/helpers/test_pydantic_2_6_migration.py::test_bytes_errors_format[Not a Number] FAILED
_________________________________ test_bytes_errors_format[Not a Number] _________________________________

params = {'expected': [{'input': 'tenMib', 'loc': ('byte_size',), 'msg': 'could not parse value and unit from byte string', 'type': 'byte_size'}], 'input': 'tenMib'}

    @pytest.mark.parametrize(
        "params",
        [
            pytest.param(
                {
                    "input": "4x",
                    "expected": [
                        {
                            "ctx": {"unit": "x"},
                            "input": "4x",
                            "loc": ("byte_size",),
                            "msg": "could not interpret byte unit: x",
                            "type": "byte_size_unit",
                        },
                    ],
                },
                id="invalid unit",
            ),
            pytest.param(
                {
                    "input": "tenMib",
                    "expected": [
                        {
                            "input": "tenMib",
                            "loc": ("byte_size",),
                            "msg": "could not parse value and unit from byte string",
                            "type": "byte_size",
                        },
                    ],
                },
                id="Not a Number",
            ),
        ],
    )
    def test_bytes_errors_format(params):
        with pytest.raises(ValidationError) as exc:
            PydanticBytes.model_validate({"byte_size": params["input"]})

>       assert exc.value.errors() == params["expected"]
E       assert [{'type': 'string_pattern_mismatch', 'loc': ('byte_size', 'constrained-str'), 'msg': "String should match pattern '^\\s*(\\d*\\.?\\d+)\\s*(\\w+)?'", 'input': 'tenMib', 'ctx': {'pattern': '^\\s*(\\d*\\.?\\d+)\\s*(\\w+)?'}, 'url': 'https://errors.pydantic.dev/2.6/v/string_pattern_mismatch'}, {'type': 'int
_parsing', 'loc': ('byte_size', 'constrained-int'), 'msg': 'Input should be a valid integer, unable to parse string as an integer', 'input': 'tenMib', 'url': 'https://errors.pydantic.dev/2.6/v/int_parsing'}] == [{'input': 'tenMib', 'loc': ('byte_size',), 'msg': 'could not parse value and unit from byte string', 'type'
: 'byte_size'}]
E         At index 0 diff: {'type': 'string_pattern_mismatch', 'loc': ('byte_size', 'constrained-str'), 'msg': "String should match pattern '^\\s*(\\d*\\.?\\d+)\\s*(\\w+)?'", 'input': 'tenMib', 'ctx': {'pattern': '^\\s*(\\d*\\.?\\d+)\\s*(\\w+)?'}, 'url': 'https://errors.pydantic.dev/2.6/v/string_pattern_mismatch'} !=
{'input': 'tenMib', 'loc': ('byte_size',), 'msg': 'could not parse value and unit from byte string', 'type': 'byte_size'}
E         Left contains one more item: {'input': 'tenMib', 'loc': ('byte_size', 'constrained-int'), 'msg': 'Input should be a valid integer, unable to parse string as an integer', 'type': 'int_parsing', ...}
E         Full diff:
E           [
E         +  {'ctx': {'pattern': '^\\s*(\\d*\\.?\\d+)\\s*(\\w+)?'},
E         +   'input': 'tenMib',
E         +   'loc': ('byte_size',
E         +           'constrained-str'),
E         +   'msg': "String should match pattern '^\\s*(\\d*\\.?\\d+)\\s*(\\w+)?'",
E         +   'type': 'string_pattern_mismatch',
E         +   'url': 'https://errors.pydantic.dev/2.6/v/string_pattern_mismatch'},
E            {'input': 'tenMib',
E         -   'loc': ('byte_size',),
E         ?                       --
E         +   'loc': ('byte_size',
E         -   'msg': 'could not parse value and unit from byte string',
E         -   'type': 'byte_size'},
E         +           'constrained-int'),
E         +   'msg': 'Input should be a valid integer, unable to parse string as an '
E         +          'integer',
E         +   'type': 'int_parsing',
E         +   'url': 'https://errors.pydantic.dev/2.6/v/int_parsing'},
E           ]

sequoia/base3/tests/helpers/test_pydantic_2_6_migration.py:47: AssertionError

Example Code

import pytest
from pydantic import BaseModel, ByteSize, Field, ValidationError


class PydanticBytes(BaseModel):
    byte_size: ByteSize = Field()


@pytest.mark.parametrize(
    "params",
    [
        pytest.param(
            {
                "input": "4x",
                "expected": [
                    {
                        "ctx": {"unit": "x"},
                        "input": "4x",
                        "loc": ("byte_size",),
                        "msg": "could not interpret byte unit: x",
                        "type": "byte_size_unit",
                    },
                ],
            },
            id="invalid unit",
        ),
        pytest.param(
            {
                "input": "tenMib",
                "expected": [
                    {
                        "input": "tenMib",
                        "loc": ("byte_size",),
                        "msg": "could not parse value and unit from byte string",
                        "type": "byte_size",
                    },
                ],
            },
            id="Not a Number",
        ),
    ],
)
def test_bytes_errors_format(params):
    with pytest.raises(ValidationError) as exc:
        PydanticBytes.model_validate({"byte_size": params["input"]})

    assert exc.value.errors() == params["expected"]

Python, Pydantic & OS Version

pydantic version: 2.6.0
        pydantic-core version: 2.16.1
          pydantic-core build: profile=release pgo=true
                 install path: /home/guillaume/.cache/pypoetry/virtualenvs/sequoia-base3-oGZ-ftSE-py3.11/lib/python3.11/site-packages/pydantic
               python version: 3.11.6 (main, Nov 14 2023, 09:36:21) [GCC 13.2.1 20230801]
                     platform: Linux-6.7.0-arch3-1-x86_64-with-glibc2.38
             related packages: typing_extensions-4.7.1
                       commit: unknown

[sydney-runkle]

@mardiros,

Thanks for the report. We'll look into a fix for this to be included in a patch release soon!

[sydney-runkle]

Broken in this PR: https://github.com/pydantic/pydantic/pull/8537/files

[sydney-runkle]

@mardiros,

I've opened a PR that should fix this issue. Thanks for bringing this to our attention!

[mardiros]

Thanks for the reactivity. Awesome job!