Currently we only have the one event format version defined, but this
adds the necessary infrastructure to persist and fetch the format
versions alongside the events.
We specify the format version rather than the room version as:
1. We don't necessarily know the room version, existing events may be
either v1 or v2.
2. We'd need to be careful to prevent/handle correctly if different
events in the same room reported to be of different versions, which
sounds annoying.
If we receive an event that doesn't pass their content hash check (e.g.
due to already being redacted) then we hit a bug which causes an
exception to be raised, which then promplty stops the event (and
request) from being processed.
This effects all sorts of federation APIs, including joining rooms with
a redacted state event.
We don't want to bother pulling out the current state from the DB since
until we know we have to. Checking the context for state is just an
optimisation.
They raised KeyError before. I'm changing this because the code uses
hasattr() to check for the presence of a key. This worked accidentally
before, because hasattr() silences all exceptions in python 2. However,
in python3, this isn't the case anymore.
I had a look around to see if anything depended on this raising a
KeyError and I couldn't find anything. Of course, I could have simply
missed it.
Signed-off-by: Adrian Tschira <nota@notafile.com>
* Split state group persist into seperate storage func
* Add per database engine code for state group id gen
* Move store_state_group to StateReadStore
This allows other workers to use it, and so resolve state.
* Hook up store_state_group
* Fix tests
* Rename _store_mult_state_groups_txn
* Rename StateGroupReadStore
* Remove redundant _have_persisted_state_group_txn
* Update comments
* Comment compute_event_context
* Set start val for state_group_id_seq
... otherwise we try to recreate old state groups
* Update comments
* Don't store state for outliers
* Update comment
* Update docstring as state groups are ints
