This was introduced in commit bde6442c47 but the rationale for it is
pretty shaky. No other non-Charybdis-derived servers send it and the
features the original commit claims it can be used to detect all have
their own methods of detection. The concept of "core capabilities" and
versioned releases was also dropped by IRCv3 many years ago in favour
of living specifications.
* move has_common_channel to s_user.c
* don't remove clients from /accept on NICK when there's a common channel
Co-authored-by: Ed Kellett <e@kellett.im>
We were ending the flood grace period for any channel mode command other
than `MODE #foo [bq]` by means of a hardcoded check. I've moved that to
after we parse the mode string, so we can correctly identify all
requests to change modes and end the grace period on exactly those.
It would have been entirely possible to move the check even further down
and flood_endgrace on only mode commands that *actually* change modes,
but I don't like the idea of making it sensitive to external conditions.
A netwide snote eventually calls into this function again with the same
server as has already been determined is over its sendq. Mark the link
dead before sending the snote to avoid infinite recursion.
Incoming MODE processing is split into a parsing step and an execution
step, instead of a mode's effector function being involved in its own
parsing. Modes can no longer use custom logic to control their parsing,
and instead supply a combination of CHM_* flags to the parser. As a
result, we know before we try to effect any mode changes what all of
them will be.
The reauthorize hack for override is no longer necessary. A side effect
of its introduction was that `MODE #foo b x!y@z` no longer worked; in
removing it we restore that behaviour.
We gain the ability to reject various invalid inputs that:
- mutate or query unknown modes
- supply excess mode arguments
- query modes that can't be queried
In each case, whether we *should* reject it is an open question; for now
I'm rejecting the first one.
The algorithm we're using gets stuck if it has a ? and can only see a *
to feed to it, even if it could skip over that * and consume a character
following it. Remedy this by rearranging the input so * always precedes
? in runs of wildcards, so when we're matching ? we know we can skip
things.
