assuan_read_from_server() and return value

[Marcus Brinkmann]

At Wed, 12 Dec 2007 15:47:18 +0100,
Marcus Brinkmann wrote:
> However, I want to clear up the following issues: Why you actually
> encounter this code path (it seems you should have an inquire cb but
> don't), and if sending END and reading from the server is the right
> thing to do anyway.

Werner points out that gpg-connect-agent sends CANCEL when an inquire
without a handler is encountered.  This seems to support my idea to do
the same in libassuan if no callback handler is registered.

But there is a related issue documented in the source code, see
dirmngr-client.c and the TODO item in libassuan.  Dirmngr client
returns an error instead of sending CANCEL upon seeing an unknown
inquire, causing assuan_transact to send END.

We need to properly specify what should happen and make sure that we
don't break anything.  I'll see what I can come up with.

Thanks,
Marcus