Verify friend error

[ayjemabo]

Steps to reproduce

1. I try to verify my friend (it worked before)
2. it showed error

Outcome

What did you expect? verify my friend

What happened instead? error

Operating system

macOS

Browser information

Safari Version 26.2 (21623.1.14.11.9)

URL for webapp

No response

Application version

No response

Homeserver

matrix.org

Will you send logs?

Yes

[kaylendog]

We are hitting this error in RustVerificationRequest.phase which supposedly shouldn't happen:

case RustSdkCryptoJs.VerificationRequestPhase.Transitioned:
    if (!this._verifier) {
        // this shouldn't happen, because the onChange handler should have created a _verifier.
        throw new Error("VerificationRequest: inner phase == Transitioned but no verifier!");
    }
    return this._verifier.verificationPhase;

However, I do believe this branch can occur. Both RustVerificationRequest.pending and VerificationRequest::changes lock the request state for reading, which RwLock allows in parallel:

• RustVerificationRequest.pending calls this.inner.phase() (VerificationRequest::phase) calls VerificationRequest::state calls self.inner.read, locking request state for reading
• RustVerificationRequest.onChange registered as callback to VerificationRequest::changes stream, which repeatedly locks the request state state for reading

This may be the very unlikely case where pending is accessed concurrently with the execution of onChange.

[kaylendog]

This has occurred before, almost two years ago: #27314

[kaylendog]

Hmm, I don't think my concurrent access theory is correct, manually delaying the onChange handler to try and force a replication doesn't seem to work.

@ayjemabo were you able to verify correctly after an app restart?

[kaylendog]

Going to close this since my attempts to replicate it have failed, and I haven't heard back whether verification was then successful after a restart.