connect_kwargs ambiguity check is too ambiguous

[tjstub]

For Fabric 2.5 on python 3.6 (Ubuntu 18.04.1)

For the following call, I would expect this to work.

import fabric
connect_kwargs = {"username": "foo", "password": "bar"}
with fabric.Connection(host=host, port=22, connect_kwargs=connect_kwargs) as conn:
           ...

instead, I receive

ValueError: Refusing to be ambiguous: connect() kwarg 'username' was given both via regular arg and via connect_kwargs!

This error is confusing and probably wrong. If username is set to None, there should be nothing to be ambiguous about, but if the current behavior is upheld, the error message should probably change. I don't recall this being a problem in older releases.

[asciifaceman]

I believe this issue is arising because fabric is merging ~/.ssh/config with your given config. I am seeing this even when username is not in kwargs because fabric is adding it on its own

connection.py - 406:409

        # NOTE: we load SSH config data as early as possible as it has
        # potential to affect nearly every other attribute.
        #: The per-host SSH config data, if any. (See :ref:`ssh-config`.)
        self.ssh_config = self.config.base_ssh_config.lookup(host)

imho this should be optional behavior as it is introducing unexpected behavior to explicit connection arguments

[dreambeyondorange]

So was there any resolution to this?