This adds a module API which allows a module to update a user's
presence state/status message. This is useful for controlling presence
from an external system.

To fully control presence from the module the presence.enabled config
parameter gains a new state of "untracked" which disables internal tracking
of presence changes via user actions, etc. Only updates from the module will
be persisted and sent down sync properly).

Fixes #16417

This splits thinsg into two queries, but most of the time we won't have
new event backwards extremities so this shouldn't actually add an extra
RTT for the majority of cases.

Note this removes the check for events with no prev events, but that was
part of MSC2716 work that has since been removed.

Fixes #15502

m.push_rules, like m.fully_read, is a special account data type that cannot
be set using the normal /account_data endpoint. Return an error instead
of allowing data that will not be used to be stored.

This change fixes a rare bug where initial /syncs would fail with a
`KeyError` under the following circumstances:
 1. A user fast joins a remote room.
 2. The user is kicked from the room before the room's full state has
    been synced.
 3. A second local user fast joins the room.
 4. Events are backfilled into the room with a higher topological
    ordering than the original user's leave. They are assigned a
    negative stream ordering. It's not clear how backfill happened here,
    since it is expected to be equivalent to syncing the full state.
 5. The second local user leaves the room before the room's full state
    has been synced. The homeserver does not complete the sync.
 6. The original user performs an initial /sync with lazy_load_members
    enabled.
     * Because they were kicked from the room, the room is included in
       the /sync response even though the include_leave option is not
       specified.
     * To populate the room's timeline, `_load_filtered_recents` /
       `get_recent_events_for_room` fetches events with a lower stream
       ordering than the leave event and picks the ones with the highest
       topological orderings (which are most recent). This captures the
       backfilled events after the leave, since they have a negative
       stream ordering. These events are filtered out of the timeline,
       since the user was not in the room at the time and cannot view
       them. The sync code ends up with an empty timeline for the room
       that notably does not include the user's leave event.
       This seems buggy, but at least we don't disclose events the user
       isn't allowed to see.
     * Normally, `compute_state_delta` would fetch the state at the
       start and end of the room's timeline to generate the sync
       response. Since the timeline is empty, it fetches the state at
       `min(now, last event in the room)`, which corresponds with the
       second user's leave. The state during the entirety of the second
       user's membership does not include the membership for the first
       user because of partial state.
       This part is also questionable, since we are fetching state from
       outside the bounds of the user's membership.
     * `compute_state_delta` then tries and fails to find the user's
       membership in the auth events of timeline events. Because there
       is no timeline event whose auth events are expected to contain
       the user's membership, a `KeyError` is raised.

Also contains a drive-by fix for a separate unlikely race condition.

Signed-off-by: Sean Quah <seanq@matrix.org>

When pushing events in partial state rooms down incremental /sync, we
try to find the `m.room.member` state event for their senders by digging
through their auth events, so that we can present the membership to the
client. Events usually have a membership event in their auth events,
with the exception of the `m.room.create` event and a user's first join
into the room.

When implementing #13477, we took the case of a user's first join into
account, but forgot to handle the `m.room.create` case. This change
fixes that.

Signed-off-by: Sean Quah <seanq@matrix.org>

...when lazy loading of members is not enabled. It's weird to notify
a client that another user's device list has changed when the client
doesn't think that they share a room.

Note that when a room is un-partial stated, device list updates are
emitted for every member in that room over /sync.

Signed-off-by: Sean Quah <seanq@matrix.org>

It's important that collections returned from `@cached` methods are not
modified, otherwise future retrievals from the cache will return the
modified collection.

This applies to the return values from `@cached` methods and the values
inside the dictionaries returned by `@cachedList` methods. It's not
necessary for the dictionaries returned by `@cachedList` methods
themselves to be read-only.

Signed-off-by: Sean Quah <seanq@matrix.org>
Co-authored-by: David Robertson <davidr@element.io>

The per-room account data is no longer unconditionally
fetched, even if all rooms will be filtered out.

Global account data will not be fetched if it will all be
filtered out.

If a sync request does not need to calculate per-room entries &
is not generating presence & is not generating device list data
(e.g. during initial sync) avoid the expensive calculation of room
specific data.

This is a micro-optimisation for clients syncing simply to receive
to-device information.

This expands the previous optimisation from being only for initial
sync to being for all sync requests.

It also inverts some of the logic to be inclusive instead of exclusive.

Due to the increased safety of StrCollection over Collection[str]
and Sequence[str].

* Batch look-ups to see if rooms are partial stated.

* Fix issues found in linting.

* Fix typo.

* Apply suggestions from code review

Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>

* Clarify comments.

Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>

* Also improve the cache size while we're at it

* is_partial_state_rooms -> is_partial_state_room_batched

* Run `black`

* Improve annotation for `simple_select_many_batch`

* Fix is_partial_state_room_batched impl

* Okay, _actually_ fix impl

* Update description.

* Update synapse/storage/databases/main/room.py

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>

* Run black.

Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>
Co-authored-by: David Robertson <davidr@element.io>

* Allow `AbstractSet` in `StrCollection`

Or else frozensets are excluded. This will be useful in an upcoming
commit where I plan to change a function that accepts `List[str]` to
accept `StrCollection` instead.

* `rooms_to_exclude` -> `rooms_to_exclude_globally`

I am about to make use of this exclusion mechanism to exclude rooms for
a specific user and a specific sync. This rename helps to clarify the
distinction between the global config and the rooms to exclude for a
specific sync.

* Better function names for internal sync methods

* Track a list of excluded rooms on SyncResultBuilder

I plan to feed a list of partially stated rooms for this sync to ignore

* Exclude partial state rooms during eager sync

using the mechanism established in the previous commit

* Track un-partial-state stream in sync tokens

So that we can work out which rooms have become fully-stated during a
given sync period.

* Fix mutation of `@cached` return value

This was fouling up a complement test added alongside this PR.
Excluding a room would mean the set of forgotten rooms in the cache
would be extended. This means that room could be erroneously considered
forgotten in the future.

Introduced in #12310, Synapse 1.57.0. I don't think this had any
user-visible side effects (until now).

* SyncResultBuilder: track rooms to force as newly joined

Similar plan as before. We've omitted rooms from certain sync responses;
now we establish the mechanism to reintroduce them into future syncs.

* Read new field, to present rooms as newly joined

* Force un-partial-stated rooms to be newly-joined

for eager incremental syncs only, provided they're still fully stated

* Notify user stream listeners to wake up long polling syncs

* Changelog

* Typo fix

Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>

* Unnecessary list cast

Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>

* Rephrase comment

Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>

* Another comment

Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>

* Fixup merge(?)

* Poke notifier when receiving un-partial-stated msg over replication

* Fixup merge whoops

Thanks MV :)

Co-authored-by: Mathieu Velen <mathieuv@matrix.org>

Co-authored-by: Mathieu Velten <mathieuv@matrix.org>
Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>

Back-out some changes from 7e582a25f8
(#14786) which skipped necessary logic to calculate device lists properly.

This has two related changes:

* It enables fast-path processing for an empty filter (`[]`) which was
  previously only used for wildcard not-filters (`["*"]`).
* It special cases a `/sync` filter with no-rooms to skip all room
  processing, previously we would partially skip processing, but would
  generally still calculate intermediate values for each room which were
  then unused.

Future changes might consider further optimizations:

* Skip calculating per-room account data when all rooms are filtered (currently
  this is thrown away).
* Make similar improvements to other endpoints which support filters.

* Move `StateFilter` to `synapse.types`

* Changelog

A batch of changes intended to make it easier to trace to-device messages through the system.

The intention here is that a client can set a property org.matrix.msgid in any to-device message it sends. That ID is then included in any tracing or logging related to the message. (Suggestions as to where this field should be documented welcome. I'm not enthusiastic about speccing it - it's very much an optional extra to help with debugging.)

I've also generally improved the data we send to opentracing for these messages.

Help callers from using the return value incorrectly by ensuring
that callers explicitly check if there was a cache hit or not.

* Use `device_one_time_keys_count` to match MSC3202

Rename the `device_one_time_key_counts` key in responses to
`device_one_time_keys_count` to match the name specified by MSC3202.

Also change related variable/class names for consistency.

Signed-off-by: Andrew Ferrazzutti <andrewf@element.io>

* Update changelog.d/14565.misc

* Revert name change for `one_time_key_counts` key

as this is a different key altogether from `device_one_time_keys_count`,
which is used for `/sync` instead of appservice transactions.

Signed-off-by: Andrew Ferrazzutti <andrewf@element.io>

* Pull out hero selection logic

* Include heroes in partial join response's state

* Changelog

* Fixup trial test

* Remove TODO

These are both part of Matrix 1.4 which has now been released.

For now, support both the unstable and stable identifiers.

By getting the joined rooms before the current token we avoid any reading
history to confirm a user *was* in a room. We can then use any membership
change events, which we already fetch during sync, to determine the final
list of joined room IDs.

When retrieving counts of notifications segment the results based on the
thread ID, but choose whether to return them as individual threads or as
a single summed field by letting the client opt-in via a sync flag.

The summarization code is also updated to be per thread, instead of per
room.

During a `lazy_load_members` `/sync`, we look through auth events in
rooms with partial state to find prior membership events. When such a
membership is not found, an error is logged.

Since the first join event for a user never has a prior membership event
to cite, the error would always be logged when one appeared in the room
timeline.

Avoid logging errors for such events.

Introduced in #13477.

Signed-off-by: Sean Quah <seanq@matrix.org>

Signed-off-by: Sean Quah <seanq@matrix.org>

The profile objects are never used and increase cache size significantly.

Use a state filter or accept partial state in a few places where we
request state, to avoid blocking.

To make lazy-loading `/sync`s work, we need to provide the memberships
of event senders, which are not guaranteed to be in the room state.
Instead we dig through auth events for memberships to present to
clients. The auth events of an event are guaranteed to contain a
passable membership event, otherwise the event would have been rejected.

Note that this only covers the common code paths encountered during
testing. There has been no exhaustive checking of all sync code paths.

Fixes #13146.

Signed-off-by: Sean Quah <seanq@matrix.org>

Add some miscellaneous comments to document sync, especially around
`compute_state_delta`.

Signed-off-by: Sean Quah <seanq@matrix.org>

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

Fixes #11887 hopefully.

The core change here is that `event_push_summary` now holds a summary of counts up until a much more recent point, meaning that the range of rows we need to count in `event_push_actions` is much smaller.

This needs two major changes:
1. When we get a receipt we need to recalculate `event_push_summary` rather than just delete it
2. The logic for deleting `event_push_actions` is now divorced from calculating `event_push_summary`.

In future it would be good to calculate `event_push_summary` while we persist a new event (it should just be a case of adding one to the relevant rows in `event_push_summary`), as that will further simplify the get counts logic and remove the need for us to periodically update `event_push_summary` in a background job.