Incorrect unread_notifications with some push rules

[HarHarLinks]

Description

With certain push rules set up, synapse does not increment the unread_notifications in the same /sync that receives the event triggering the push rule, violating the spec requirement

The updated notification count from a new event MUST appear in the same /sync response as the event itself.

Steps to reproduce

• create 3 accounts in an element web + synapse + mas setup
• log into all 3
• enable bob's desktop notifications
• create a room between kim and bob
• note bob's access token
• use playground.matrix.org to add a notify action to bob's .m.rule.member_event, confirm via playground and element devtools. see attachment.
• watch bob's element's `/sync' via browser devtools
• kim invites charlie
• check the /sync response, see attachment.
• (check the notification logging)

push_rules.json
sync.json

Homeserver

localhost

Synapse Version

synapse 1.122

Installation Method

Docker (matrixdotorg/synapse)

Database

fresh postgres 16 container

Workers

Single process

Platform

docker

Configuration

default

Relevant log output

🤷

Anything else that would be useful to know?

No response