Hey,

We discovered a problem with WalletConnect v2 stored subscriptions leading to a freeze/crash. Unfortunately we haven’t yet pinpointed the exact steps to reproduce this, however we’ve gathered some data about what’s happening.

Problem

We initially spotted the issue in our Valora wallet. See https://github.com/valora-inc/wallet/issues/1215. But then noticed it’s happening on the test web app we use too: https://use-contractkit-c-labs.vercel.app/

Approximate repro steps on the web app:

1. Go to https://use-contractkit-c-labs.vercel.app/
2. Tap Connect
3. Scan the QR code with Valora (note that we’ve remotely disabled WC v2 in the production versions of Valora because of this issue)
4. Sign some things (not sure it’s needed though)
5. Let the tab open for a while
6. Refresh it, it will eventually crash

This is happening with @walletconnect/client 2.0.0-beta.18.

The main problem is a huge number of subscriptions end up being stored in local storage (8000+). Once the client tries to restore them in a Promise.all call when initializing, it blows up (Chrome page errors, mobile app crashes, running out of memory). https://github.com/WalletConnect/walletconnect-monorepo/blob/56db6e088d55146249788b8a27dfb9609f5f297b/packages/client/src/controllers/relayer.ts#L291-L300

Data

Here’s the data causing this (took some screenshots, but I can provide the raw data too).

You can see it’s storing 8000+ subscriptions for basically 2 different topics:

And here are the other parts of the stored state that may be of interest.

I’ve also been able to capture the logs of Valora with WalletConnect logger in trace mode.

Note that there’s a misleading log statement:

[Fri Oct 15 2021 15:47:18.275]  DEBUG    {"context": "client"} [{"context": "client/relayer"}, {"context": "client/relayer/subscription"}, "Successfully Restored subscriptions for relayer subscription"]
[Fri Oct 15 2021 15:47:18.281]  TRACE    {"context": "client"} {"context": "client/relayer"} {"context": "client/relayer/subscription"} {"method": "restore", "subscriptions": [], "type": "method"}

It says the subscriptions are empty when it was actually 8000+ items. Not sure why it doesn’t display them.

Let me know if you need any other info.

Thanks!