TypeError: argument of type 'NoneType' is not iterable in msal_client.py

[micafer]

• Azure.Identity:
• 1.8.0:
• Ubuntu 20.04:
• Python 3.8:

Describe the bug

Sometimes when authenticating with ClientSecretCredential class I get this error:

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/dist-packages/azure/identity/_internal/decorators.py", line 56, in wrapper
    return fn(*args, **kwargs)
  File "/usr/local/lib/python3.8/dist-packages/azure/identity/_credentials/user_password.py", line 58, in _request_token
    return app.acquire_token_by_username_password(
  File "/usr/local/lib/python3.8/dist-packages/msal/application.py", line 1417, in acquire_token_by_username_password
    user_realm_result = self.authority.user_realm_discovery(
  File "/usr/local/lib/python3.8/dist-packages/msal/authority.py", line 128, in user_realm_discovery
    resp.raise_for_status()
  File "/usr/local/lib/python3.8/dist-packages/azure/identity/_internal/msal_client.py", line 55, in raise_for_status
    if "error" in content or "error_description" in content:
TypeError: argument of type 'NoneType' is not iterable

To Reproduce
Steps to reproduce the behavior:
The error appears sometimes, I cannot reproduce the error with a fixed set ot steps.

Expected behavior

It should raise a ClientAuthenticationError with the correct error.

Additional context

I suggest to change this line:
https://github.com/Azure/azure-sdk-for-python/blob/main/sdk/identity/azure-identity/azure/identity/_internal/msal_client.py#L53

from:

if ContentDecodePolicy.CONTEXT_NAME in self._response.context:

to:

if ContentDecodePolicy.CONTEXT_NAME in self._response.context and self._response.context[ContentDecodePolicy.CONTEXT_NAME]:

[catalinaperalta]

Thanks for reporting this @micafer! We'll investigate and get back to you ASAP.

[xiangyan99]

Thanks for reporting the issue. The fix has been merged and will be available in next release.

Hi @micafer. Thank you for opening this issue and giving us the opportunity to assist. We believe that this has been addressed. If you feel that further discussion is needed, please add a comment with the text “/unresolve” to remove the “issue-addressed” label and continue the conversation.