Regression of case sensitive environment variable support

[slingshotsys]

As of v2.5.0 case sensitive environment variables no longer function properly:

import os

from pydantic import BaseModel
from pydantic_settings import BaseSettings, SettingsConfigDict

class NestedSettings(BaseModel):
    A: str
    b: int

class Settings(BaseSettings):
    not_nested: str
    NESTED: NestedSettings | None
    NestedTwo: NestedSettings | None

    model_config = SettingsConfigDict(
        case_sensitive=True,
        extra="forbid",
    )

os.environ["not_nested"] = "test"
os.environ["NESTED"] = '{"A": "10", "b": "10"}'
os.environ["NestedTwo"] = '{"a": "10", "b": "10"}'

print(Settings())

result:

pydantic_core._pydantic_core.ValidationError: 2 validation errors for Settings
not_nested
  Field required [type=missing, input_value={'NESTED': {'a': '10', 'b': '10'}}, input_type=dict]
    For further information visit https://errors.pydantic.dev/2.9/v/missing
NestedTwo
  Field required [type=missing, input_value={'NESTED': {'a': '10', 'b': '10'}}, input_type=dict]
    For further information visit https://errors.pydantic.dev/2.9/v/missing

changing case_sensitive to False works as expected.

see: #295

[hramezani]

Thanks @slingshotvfx for reporting.

Is it happening on Windows?

[slingshotsys]

On Windows 11 in Python 3.12.1

I misspoke actually, this is a regression maybe all the way back to v2.2.0

[hramezani]

Thanks for your quick response @slingshotvfx .

my question is why do you enable the case_sensitive in your model. as you said you are using windows and this config doesn't have any effect on windows:

from the doc:
On Windows, Python's os module always treats environment variables as case-insensitive, so the case_sensitive config setting will have no effect - settings will always be updated ignoring case.

[slingshotsys]

Our code is cross-platform and we utilize case_sensitive for our Linux deployments. I admit having case_sensitive=True in windows code is misleading if it really does nothing, but ideally it would still work and not throw a validation error.

[hramezani]

One solution would be to set case_sensitive=False when pydantic-settings in on Windows.

But you can do it on your side as well. like

case_sensitive=False if sys.platform.startswith('win') else True,

[slingshotsys]

I suppose that would work. The docs are a bit misleading though, since the case_sensitive config setting will have no effect implies that it doesn't matter if it's True or False and yet the behavior does change on windows when it's set to True.

I actually bumped into this while troubleshooting #420, but I'm realizing now that that issue is unrelated and I think this issue is just a duplicate of #295 rather than a regression. Apologies for the confusion.

[hramezani]

No worries, let's mark this one as duplicate and close.