Follow on from https://github.com/element-hq/synapse/pull/19701.
Unfortunately serde has a bug when using `#[serde(flatten)]` with
`arbitrary-precision` feature when handling integers that fit in a i128
when doing `serde_json::from_value`. See
https://github.com/serde-rs/serde/issues/2230.
The `depythonize` hits the same issue. To fix this we make it so we only
parse events from strings and not values.
Based on #19708.
This is on the path to porting the entire event class to Rust, as
`event.content` will then return the new Rust class `JsonObject`.
This PR adds a pure Rust `JsonObject` class that is a `Mapping`
representing a json-style object. It uses `serde_json::Value` as its
in-memory representation and `pythonize` for conversion when a field is
looked up on the object.
I'm not thrilled with the name, but couldn't think of a better one.
This also adds `JsonObject` handling to the JSON serialisation functions
we use, as well as to the `freeze(..)` function.
Reviewable commit-by-commit.
The Rust port of `KNOWN_ROOM_VERSIONS` (#19589) made `__contains__`
strict about key types, raising `TypeError` when called with `None`
instead of returning `False` like a Python dict would.
This broke `/sync` for rooms with a NULL `room_version` in the database.
```
File "/home/synapse/src/synapse/handlers/sync.py", line 2628, in _get_room_changes_for_initial_sync
if event.room_version_id not in KNOWN_ROOM_VERSIONS:
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: argument 'key': 'NoneType' object cannot be cast as 'str'
```