matrix-org / matrix-org/matrix-rust-sdk
Sync and `get_members` can race in setting member events
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- Dominant language
- Rust
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Description
In https://github.com/matrix-org/matrix-rust-sdk/pull/1134 we removed the check to only set members events if they didn't exist before. get_members now sets all the the member events from the response.
If we sync at the same time, it might happen that both sync and get_members write to the member events at the same time and race, possibly overwriting up to date information with less up to date ones?
Quote on how to fix this by @poljar :
One idea is that there should be a way to know which users are currently being added via the sync so that we can skip them, I think Hydrogen does something along those lines.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
No file or test is named. Start by reviewing PR 1134 and tracing the sync and get_members paths where member events are written concurrently. Done means concurrent operations cannot overwrite newer member information with older data; add focused coverage for that race.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- backend, distributed-systems
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 35/100