Figuring out how to correctly limit updates from this stream without dropping
entries is far more complicated than just counting the number of rows being
returned. We need to consider each query separately and, if any one query hits
the limit, truncate the results from the others.

I think this also fixes some potentially long-standing bugs where events or
state changes could get missed if we hit the limit on either query.

there doesn't seem to be much point in passing this limit all around, since
both sides agree it's meant to be 100.

This reverts commit 1adf6a55.

This reverts commit 6f431936, reversing
changes made to 0d775fcc.

Config option to inhibit 3PID errors on /requestToken

Long story short: if we're handling presence on the current worker, we shouldn't be sending USER_SYNC commands over replication.

In an attempt to figure out what is going on here, I ended up refactoring some bits of the presencehandler code, so the first 4 commits here are non-functional refactors to move this code slightly closer to sanity. (There's still plenty to do here :/). Suggest reviewing individual commits.

Fixes (I hope) #7257.

Adds a request_token_inhibit_errors configuration flag (disabled by
default) which, if enabled, change the behaviour of all /requestToken
endpoints so that they return a 200 and a fake sid if the 3PID was/was
not found associated with an account (depending on the endpoint),
instead of an error.

Co-Authored-By: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>

Synapse 1.12.4rc1 (2020-04-22)
==============================

Features
--------

- Always send users their own device updates. ([\#7160](https://github.com/matrix-org/synapse/issues/7160))
- Add support for handling GET requests for `account_data` on a worker. ([\#7311](https://github.com/matrix-org/synapse/issues/7311))

Bugfixes
--------

- Fix a bug that prevented cross-signing with users on worker-mode synapses. ([\#7255](https://github.com/matrix-org/synapse/issues/7255))
- Do not treat display names as globs in push rules. ([\#7271](https://github.com/matrix-org/synapse/issues/7271))
- Fix a bug with cross-signing devices belonging to remote users who did not share a room with any user on the local homeserver. ([\#7289](https://github.com/matrix-org/synapse/issues/7289))

I messed this up last time I tried (#7239 / e13c6c7a).

First some background: StreamChangeCache is used to keep track of what "entities" have 
changed since a given stream ID. So for example, we might use it to keep track of when the last
to-device message for a given user was received [1], and hence whether we need to pull any to-device messages from the database on a sync [2].

Now, it turns out that StreamChangeCache didn't support more than one thing being changed at
a given stream_id (this was part of the problem with #7206). However, it's entirely valid to send
to-device messages to more than one user at a time.

As it turns out, this did in fact work, because *some* methods of StreamChangeCache coped
ok with having multiple things changing on the same stream ID, and it seems we never actually
use the methods which don't work on the stream change caches where we allow multiple
changes at the same stream ID. But that feels horribly fragile, hence: let's update
StreamChangeCache to properly support this, and add some typing and some more tests while
we're at it.

[1]: https://github.com/matrix-org/synapse/blob/release-v1.12.3/synapse/storage/data_stores/main/deviceinbox.py#L301
[2]: https://github.com/matrix-org/synapse/blob/release-v1.12.3/synapse/storage/data_stores/main/deviceinbox.py#L47-L51

This is configured via the `redis` config options.

Splitting based on the response code means we can avoid double logging here and identical information from line 164 while still logging at info if we don't get a good response and need to retry.

I updated the PR and forgot to update the changelog.

This was incorrectly merged to the release branch before it was ready.

This reverts commit 72fe2aff.

Also adjust sample_config.yaml

Signed-off-by: Lars Franke <frcl@mailbox.org>

Other parts of the code (such as the StreamChangeCache) assume that there will
not be multiple changes with the same stream id.

This code was introduced in #7024, and I hope this fixes #7206.

Signed-off-by: James Hebden <james@ec0.io>

Add changelog

Save retrieved keys to the db

lint

Fix and de-brittle remote result dict processing

Use query_user_devices instead, assume only master, self_signing key types

Make changelog more useful

Remove very specific exception handling

Wrap get_verify_key_from_cross_signing_key in a try/except

Note that _get_e2e_cross_signing_verify_key can raise a SynapseError

lint

Add comment explaining why this is useful

Only fetch master and self_signing key types

Fix log statements, docstrings

Remove extraneous items from remote query try/except

lint

Factor key retrieval out into a separate function

Send device updates, modeled after SigningKeyEduUpdater._handle_signing_key_updates

Update method docstring

The general idea here is to get rid of the type: ignore annotations on all of the current_token and update_function assignments, which would have caught #7290.

After a bit of experimentation, it seems like the least-awful way to do this is to pass the offending functions in as parameters to the Stream constructor. Unfortunately that means that the concrete implementations no longer have the same constructor signature as Stream itself, which means that it gets hard to correctly annotate STREAMS_MAP.

I've also introduced a couple of new types, to take out some duplication.