Fixes https://github.com/matrix-org/matrix-doc/issues/1166
Fixes https://github.com/matrix-org/matrix-doc/issues/1527
Fixes https://github.com/matrix-org/matrix-doc/issues/1827
Note: In order to fix the "state events have the following fields: [no words]" bug (1827) we need to resolve references on common event types. When doing this we ultimately end up with more fields than may be required to explain the section, however this commit alters the section descriptions to just say "these fields" instead of "these additional fields".
This is also preferable over trying to get the inheritance reversed in the common event types, as the `/sync` endpoint has a high amount of reliance on partial events definitions.
Original proposal: https://github.com/matrix-org/matrix-doc/pull/1659
Implementation proofs (some traversing of the PR tree may be required to get all of them):
* https://github.com/matrix-org/synapse/pull/4483
* https://github.com/matrix-org/synapse/pull/4499
This doesn't intentionally change anything from the proposal.
**Implementation details**:
The simple part of this is the introduction of a rooms/v3.html document. The somewhat unclear part is the stuff done to the s2s definitions. This pulls `unsigned_pdu` out to `unsigned_pdu_base` (all fields except `event_id`) where it can be reused in `pdu` and `pdu_v3` (for rooms v3). These definitions are further moved into the room version specifications where they can highlight the exact schemas in detail.
Version 1 has been updated to include the pre-existing event format, however the core principles of the room have not been changed. The same applies to room version 2. Room versions have immutable core principles once in the spec, otherwise these format changes would land in a pre-existing version.
The client-server API event formats will need updating, however that is being punted to a different commit to try and keep these changes reviewable.
Instead of trying to describe maturity, stability, and recommendedness in one list we should describe what is "safe" and "unsafe" to use. The default version is just something that servers should use, and is normally going to be stable.
Versions are actually on a scale of recommendations, and are expected to be created as needed. The scale presented here (develop/beta/default/recommended/mandatory) is a more wordy version of what was previously discussed/intended for room versions - the labels aren't final and may be changed.
We're licensing hte spec under ASLv2. Add the LICENSE file, and add the
short-form to as much of the source as is practical right now (adding it to
json source is a massive pita).