Hi,

Is there any good solution for the scenario of an auth_challenge() with two separate transaction suspensions?

To clarify (simplified):

    request_route {
        ...

        t_newtran();

        if(!is_present_hf("Authorization") && !is_present_hf("Proxy-Authorization")) {
           auth_challenge("$fd", "1");
           exit;
        }

        # TM suspend/continue
        t_newtran();

        async credentials query("RESUME_AUTH");
    }

    route[RESUME_AUTH] {
        # Credentials received into PVs.

        if(!pv_auth_check("...")) {
            auth_challenge("$fd", "1");
            exit;
        }

        # Create transaction shell if not exists already from auth query.
        if(!t_lookup_request())
           t_newtran();

        # TM suspend/continue
        async route query("RESUME_ROUTING");
    }

    route[RESUME_ROUTING] {
        # Unmarshal etc.

        t_relay(); # etc.
    }

What happens here is that the first auth_challenge() results in a retransmission of its 407 challenge without absorbing the negative ACK. This is despite the ostensibly stateful behaviour of auth_challenge() without "force_stateless_reply" enabled.

In this case, it eclipses the second, unrelated 407 challenge from the subsequent routing query (407 challenge with +1 CSeq):