This is a large change and as such, it needs good motivation. Let me
remind you of the ultimate goal: we want a derive macro which allows us
to FromXml/IntoXml, and that derive macro should be usable from
`xmpp_parsers` and other crates.
For that, any code generated by the derive macro mustn't depend on any
code in the `xmpp_parsers` crate, because you cannot name the crate you
are in portably (`xmpp_parsers::..` wouldn't resolve within
`xmpp_parsers`, and `crate::..` would point at other crates if the macro
was used in other crates).
We also want to interoperate with code already implementing
`TryFrom<Element>` and `Into<Element>` on structs. This ultimately
requires that we have an error type which is shared by the two
implementations and that error type must be declared in the `xso` crate
to be usable by the macros.
Thus, we port the error type over to use the type declared in `xso`.
This changes the structure of the error type greatly; I do not think
that `xso` should have to know about all the different types we are
parsing there and they don't deserve special treatment. Wrapping them in
a `Box<dyn ..>` seems more appropriate.
xmpp-rs normally has the stance to get buggy implementations fixed
rather than dropping checks. In this particular case I think this is not
a good use of resources:
- The disco#info feature var conveys no actual information:
If an implementation replies properly to a disco#info query, it is
already implied that it supports the protocol.
- There are broken server implementations out there.
A lot of them (all recent (>= 0.10 && < 0.13 AFAICT) Prosody IM
instances). At this point in time, xmpp-rs is unable to query
disco#info from MUCs hosted on such prosody versions, except by
workarounds (such as the one removed in this diff).
- XEP-0030 now features a note which reads:
> Note: Some entities are known not to advertise the
> `http://jabber.org/protocol/disco#info` feature within their
> responses, contrary to this specification. Entities receiving
> otherwise valid responses which do not include this feature SHOULD
> infer the support.
The case would be different if there were no (deployed) implementations
which had this bug or if the bug actually had an effect on clients.
Especially the latter is not the case though, as pointed out above.
Hence, I conclude that this check is overly pedantic and the resources
(time, emotional energy of dealing with bugs, punching patches through
to stable distributions, etc. etc.) spent on getting this fixed would
be better invested elsewhere.
In addition, the workaround is extremely ugly and, even in the xmpp-rs
implementation, has no test coverage. Without test coverage of such an
implementation, it is bound to break in funny ways when xmpp-rs changes
the strings of its error messages (which is something one might do even
outside a breaking release).
Other additional checks are already gated by the absence of this
feature. As the MR to remove these checks altogether is still blocked,
this should serve as at least as an intermediate solution to anyone
affected by buggy remote implementations.
This moves InnerJid into Jid and reformulates BareJid and FullJid in
terms of Jid.
Doing this has the key advantage that FullJid and BareJid can deref to
and borrow as Jid. This, in turn, has the advantage that they can be
used much more flexibly in HashMaps. However, this is (as we say in
Germany) future music; this commit only does the internal reworking.
Oh and also, it saves 20% memory on Jid objects.
Fixes#122 more thoroughly, or rather the original intent behind it.
