Most users will connect to their server with `<username>` as their
username in order to configure their upstreams.
Multi-upstream can be unintuitive to them and should not be enabled on
that first connection that is usually used for upstream configuration.
Multi-upstream is instead a power-user feature that should be explicitly
enabled with a specific network suffix.
We reserve the network suffix `*` and use it a special case to mean that
it requests multi-upstream mode.
Instead of always requiring users to explicitly specify the network
name, guess it from the downstream connection.
Network commands are left as-is because it's not yet clear how to
handle them.
Make Network.Nick optional, default to the user's username. This
will allow adding a global setting to set the nickname in the
future, just like we have for the real name.
References: https://todo.sr.ht/~emersion/soju/110
This is a mecanical change, which just lifts up the context.TODO()
calls from inside the DB implementations to the callers.
Future work involves properly wiring up the contexts when it makes
sense.
This allows users to set a default realname used if the per-network
realname isn't set.
A new "user update" command is introduced and can be extended to edit
other user properties and other users in the future.
TL;DR: supports for casemapping, now logs are saved in
casemapped/canonical/tolower form
(eg. in the #channel directory instead of #Channel... or something)
== What is casemapping? ==
see <https://modern.ircdocs.horse/#casemapping-parameter>
== Casemapping and multi-upstream ==
Since each upstream does not necessarily use the same casemapping, and
since casemappings cannot coexist [0],
1. soju must also update the database accordingly to upstreams'
casemapping, otherwise it will end up inconsistent,
2. soju must "normalize" entity names and expose only one casemapping
that is a subset of all supported casemappings (here, ascii).
[0] On some upstreams, "emersion[m]" and "emersion{m}" refer to the same
user (upstreams that advertise rfc1459 for example), while on others
(upstreams that advertise ascii) they don't.
Once upstream's casemapping is known (default to rfc1459), entity names
in map keys are made into casemapped form, for upstreamConn,
upstreamChannel and network.
downstreamConn advertises "CASEMAPPING=ascii", and always casemap map
keys with ascii.
Some functions require the caller to casemap their argument (to avoid
needless calls to casemapping functions).
== Message forwarding and casemapping ==
downstream message handling (joins and parts basically):
When relaying entity names from downstreams to upstreams, soju uses the
upstream casemapping, in order to not get in the way of the user. This
does not brings any issue, as long as soju replies with the ascii
casemapping in mind (solves point 1.).
marshalEntity/marshalUserPrefix:
When relaying entity names from upstreams with non-ascii casemappings,
soju *partially* casemap them: it only change the case of characters
which are not ascii letters. ASCII case is thus kept intact, while
special symbols like []{} are the same every time soju sends them to
downstreams (solves point 2.).
== Casemapping changes ==
Casemapping changes are not fully supported by this patch and will
result in loss of history. This is a limitation of the protocol and
should be solved by the RENAME spec.
This adds the `channel update` service command, which is used to set the
auto-detach, auto-reattach, and message relaying settings of a channel.
Of note is that currently the parser parses `#` as a comment, which
means any `channel update #foo ...` will actually need to be escaped to
`channel update "#foo" ...`
FlagSet.PrintDefaults uses reflection to construct a zero value, calls
.String on it, and compares the result with the current flag value to
detect zero-value flags. For stringPtrFlag, this would result in a
panic, as String() always dereferenced the first level of its **string.
Add another check so that both pointer levels are nil-checked.
