Actually, this condition doesn't cover when auth_method == AuthMethod::Auto and auto chooses basic. You could use auth_method.is_basic(<path_to_credentials_toml>) instead, however, you need to parse the credentials file path, which is not available in this function.

Alternatively, if both remote_username and remote_password are set, you can consider that auth method is basic.

When Bridge Config is created, based on remote_username it is either AuthMethod::Certificate or AuthMethod::Basic. For aws and azure it is set to None. However, using if bridge_config.remote_username.is_some() && bridge_config.remote_password.is_some() is also what I considered.

When Bridge Config is created, based on remote_username it is either AuthMethod::Certificate or AuthMethod::Basic. For aws and azure it is set to None.

This is correct. So, just to fix the issue, your change is enough.

However, there is a misuse of the type in the code.

1. BridgeConfig::auth_method should have been Option<AuthType>, AuthType has only Basic or Certificate. AuthMethod is just a representation of c8y.auth_method config. Internally, we should use AuthType since it doesn't have Auto.
2. Next, what does None mean for authentication? AWS/Azure, we use certificate based authentication.

So, BridgeConfig::auth_method should be no longer Option, just AuthType.

As the condition seems no so obvious, it would be better to extract it into a BridgeConfig method.