This was all done through claude.
## Fix flaky `test_edu_large_messages_not_splitting_one_user` (`TooLong`
under `trial -jN`)
### Problem
The "Build .deb packages" CI step intermittently failed with:
```
twisted.protocols.amp.TooLong
...in
tests.rest.client.test_sendtodevice.SendToDeviceTestCase.test_edu_large_messages_not_splitting_one_user
```
The deb build runs the suite with `twisted.trial -j2`. In that mode,
worker log events are shipped to the manager process over Twisted's AMP
protocol, which encodes each value with a 2-byte length prefix — so any
single log line of **64 KiB or more** raises `TooLong`.
### Root cause
Not a bug in the to-device/EDU logic, and **not** debug logging enabled
by the build (it runs at the default `ERROR` level). It's a **log-level
leak between tests sharing a `-j2` worker**:
- `tests/logging/test_loggers.py::ExplicitlyConfiguredLoggerTestCase`
calls `root_logger.setLevel(logging.DEBUG)` directly and never restores
it (no `setUp`/`tearDown`/`addCleanup`).
- When that test runs before
`test_edu_large_messages_not_splitting_one_user` **in the same worker
process**, the root logger is left at `DEBUG`.
- That test deliberately builds an EDU of exactly `SOFT_MAX_EDU_SIZE -
1` (65 535) bytes. Storing it triggers `synapse/storage/database.py`'s
`[SQL values]` DEBUG log, which dumps the full query params — producing
a **65 708-byte**
line that overflows AMP's cap.
It looks "flaky" purely because of `-j2` scheduling: whether the two
tests land on the same worker, and in what order.
### Fix
Three commits:
1. **Restore the root logger level in
`ExplicitlyConfiguredLoggerTestCase`** — `addCleanup` to put the level
back. Fixes the root cause.
2. **Truncate oversized log lines in the test log handler**
(`ToTwistedHandler.emit`) — caps lines at 1000 chars so no debug line
can break `trial -jN`, regardless of which query is logged (defense in
depth).
3. **Truncate values in `[SQL values]` debug logging** — caps the logged
param repr at 1000 chars (guarded by `isEnabledFor(DEBUG)` to keep the
hot path lazy). Keeps production debug logs sane too.
### Testing
- The reproduction (`trial -j2 tests.logging.test_loggers <the EDU
test>`) went from **~3/8 failing** to **10/10 passing**.
- Confirmed the root level is restored after the logging tests, and that
the `[SQL values]` line is now capped (~50 KB with a `[truncated]`
marker, was 65 708).
- `ruff` + `mypy` clean; `tests.logging.test_loggers` and
`tests.rest.client.test_sendtodevice` pass (14/14).
---------
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
Co-authored-by: Eric Eastwood <erice@element.io>
See https://github.com/matrix-org/synapse/pull/14095#discussion_r990335492
This is useful because when see that a relevant event is an `outlier` or `soft-failed`, then that's a good unexpected indicator explaining why it's not showing up. `filter_events_for_client` is used in `/sync`, `/messages`, `/context` which are all common end-to-end assertion touch points (also notifications, relations).
Fix https://github.com/matrix-org/synapse/issues/15618
### Before
```
2023-05-17 22:51:36-0500 [-] 2023-05-17 22:51:36,889 - synapse.server - 338 - INFO - sentinel - Finished setting up.
```
### After
```
2023-05-19 18:16:20-0500 [-] synapse.server - 338 - INFO - sentinel - Finished setting up.
```
### Dev notes
The `Twisted.Logger` controls the `2023-05-19 18:16:20-0500 [-]` prefix, see : [`twisted/twisted` -> `src/twisted/logger/_format.py#L362-L374`](https://github.com/twisted/twisted/blob/34b161e66bc7c9f9efbb95e82c770a863933e498/src/twisted/logger/_format.py#L362-L374)
And we delegate our logs to the Twisted Logger for the tests which puts it in `_trial_temp/test.log`
Since pyo3-log is initialized very early in the Python start-up
it caches the state of the loggers before they're fully initialized
(and thus are essentially disabled). Whenever we reload the
logging configuration we now also tell pyo3-log to discard
any cached logging configuration it has; it will refetch the
current logging configuration from Python at the next point
it logs.
This fixes Rust log lines not appearing in the homeserver logs.
Over time we've begun to use newer versions of mypy, typeshed, stub
packages---and of course we've improved our own annotations. This makes
some type ignore comments no longer necessary. I have removed them.
There was one exception: a module that imports `select.epoll`. The
ignore is redundant on Linux, but I've kept it ignored for those of us
who work on the source tree using not-Linux. (#11771)
I'm more interested in the config line which enforces this. I want
unused ignores to be reported, because I think it's useful feedback when
annotating to know when you've fixed a problem you had to previously
ignore.
* Installing extras before typechecking
Lacking an easy way to install all extras generically, let's bite the bullet and
make install the hand-maintained `all` extra before typechecking.
Now that https://github.com/matrix-org/backend-meta/pull/6 is merged to
the release/v1 branch.
Part of #9744
Removes all redundant `# -*- coding: utf-8 -*-` lines from files, as python 3 automatically reads source code as utf-8 now.
`Signed-off-by: Jonathan de Jong <jonathan@automatia.nl>`
Erik Johnston