This fixes the case with multiple devices on the joining side: if we observe such a message from
another device, we mark an inviter as verified and an accepted contact thus causing a subsequent
"vg-member-added" message -- in case of a verified group -- to create it properly.
This bug was introduced by 3cf78749df - there are three visibility
states: Archived, Pinned and Normal - in the database, this "visibility" is named historically
"archived" ... the original code has an AND archived=1 therefore.
It seems .abort() does not work on the recently seen loop
in some cases, e.g. if it is busy looping in a separate thread.
In my case after account reconfiguration recently seen loop
kept running and issuing warnings about closed interrupt channel.
Exit from recently seen loop on errors to avoid using 100% CPU
in such cases.
Derive Debug, PartialEq and Eq for Peerstate,
so `verifier` is included in Debug output and compared.
Store verifier as empty string
instead of NULL in the database.
- Return Result from set_verified() so that it can't be missed.
- Pass Fingerprint to set_verified() by value to avoid cloning it inside. This optimises out an
extra clone() if we already have a value that can be moved at the caller side. However, this may
add an extra clone() if set_verified() fails, but let's not optimise the fail scenario.
- If bcc_self is set, gossip headers must be added despite of the number of group members.
- If another device observes Secure-Join, instead of looking for Secure-Join-Fingerprint in
"vg-member-added"/"vc-contact-confirm" messages it must use keys from Autocrypt-Gossip headers as
described in the Countermitm doc
(https://countermitm.readthedocs.io/en/latest/new.html#joining-a-verified-group-secure-join).
This allows to distinguish exceptions,
such as database errors, from invalid user input.
For example, if the From: field of the message
does not look like an email address, the mail
should be ignored. But if there is a database
failure while writing a new contact for the address,
this error should be bubbled up.
