[Bug] KeyError: 'error' when receiving a 400+ status code

[lindycoder]

Hello!

Describe the bug
Library raises this stack trace when a > 400 status is received

../.venv/lib/python3.12/site-packages/msal/application.py:632: in __init__
    self.authority = Authority(
../.venv/lib/python3.12/site-packages/msal/authority.py:79: in __init__
    openid_config = tenant_discovery(
../.venv/lib/python3.12/site-packages/msal/authority.py:222: in tenant_discovery
    resp.raise_for_status()
../.venv/lib/python3.12/site-packages/msal/throttled_http_client.py:69: in raise_for_status
    raise MsalServiceError("HTTP Error: {}".format(self.status_code))
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = MsalServiceError('HTTP Error: 500'), args = ('HTTP Error: 500',)
kwargs = {}

    def __init__(self, *args, **kwargs):
>       super(MsalError, self).__init__(self.msg.format(**kwargs), *args)
E       KeyError: 'error'

../.venv/lib/python3.12/site-packages/msal/exceptions.py:33: KeyError

To Reproduce
Steps to reproduce the behavior:
The closest is: https://github.com/AzureAD/microsoft-authentication-library-for-python/blob/dev/sample/confidential_client_sample.py

And was reproduced in a test using requests_mock

Expected behavior
Should successfully raise a MsalServiceError i suppose

What you see instead
KeyError: 'error'

The MSAL Python version you are using
Paste the output of this
python -c "import msal; print(msal.__version__)"

1.32.3

Additional context
Seems to have been introduced here:
29d1ac1#diff-3ebc80b207eb5a4e4eae904208ad8d17cc8f7eaf23f5a7d82a185578f79898bfR61

This instantiation can't work

>>> from msal.exceptions import MsalServiceError
>>> MsalServiceError("HTTP Error: {}".format(401))

[rayluo]

Thanks for reporting. This is a bug. Its impact is considered mild, because an exception is expected to be thrown in this situation anyway. We plan to ship its fix in our next normal release cadence.

Did you run into this because your authority url was misspelled? Will you recover after specifying a correct authority?

[lindycoder]

Thank you very much!

This was discovered in integration tests where we force an error using requests-mock to validate how we handle this in our system.

[rayluo]

Fixed in #820. It will be shipped in next release.