Element R: "DomException UnknownError (0)" in console

[andybalaam]

Steps to reproduce

1. Using Element R via a new login on develop.element.io
2. Using the app normally, and it appears to work well
3. Look at the console

Outcome

What did you expect?

No errors

What happened instead?

Lots of messages like this:

Uncaught (in promise) Error: DomException UnknownError (0): The operation failed for reasons unrelated to the database itself and not covered by any other error code.
    __wbindgen_error_new matrix_sdk_crypto_wasm.js:6834
    __wbg_adapter_59 matrix_sdk_crypto_wasm.js:274
    real matrix_sdk_crypto_wasm.js:216
    promise callback*1408/</module.exports.__wbg_then_ec5db6d509eb475f matrix_sdk_crypto_wasm.js:7636
    __wbg_adapter_56 matrix_sdk_crypto_wasm.js:270
    real matrix_sdk_crypto_wasm.js:252
    __wbg_setonerror_019196fbce756cc0 matrix_sdk_crypto_wasm.js:7332
    __wbg_adapter_59 matrix_sdk_crypto_wasm.js:274
    real matrix_sdk_crypto_wasm.js:216
    promise callback*1408/</module.exports.__wbg_then_ec5db6d509eb475f matrix_sdk_crypto_wasm.js:7636
    __wbg_adapter_658 matrix_sdk_crypto_wasm.js:334
    cb0 matrix_sdk_crypto_wasm.js:7618
    __wbg_new_9d3a9ce4282a18a8 matrix_sdk_crypto_wasm.js:7623
    backupRoomKeys matrix_sdk_crypto_wasm.js:4010
    backupKeysLoop backup.ts:276
matrix_sdk_crypto_wasm.js:6834

Operating system

Ubuntu 22.04

Browser information

Firefox 119.0

URL for webapp

https://develop.element.io

Application version

Element version: 56bdaaf-react-860764c05764-js-e0dacf75299a Crypto version: Rust SDK 0.6.0, Vodozemac 0.5.0

Homeserver

matrix.org

Will you send logs?

Yes

[richvdh]

This is odd. The error seems to reflect some indexeddb failure, in the depths of the key backup loop. (Specifically, I think it is happening in CryptoStore::inbound_group_sessions_for_backup).

Could be related to #26488, maybe?

We could do with improving the logging in this area of the codebase, anyway. This is a particular highlight:

2023-10-31T09:59:55.434Z D Starting loop for 1.

[richvdh]

I think this has now turned into

Backup: Error processing backup request for rust crypto-sdk Error: failed to read or write to the crypto store DomException UnknownError (0): The operation failed for reasons unrelated to the database itself and not covered by any other error code."

... and I think it's due to #26488. Closing as a duplicate of that for now.

[andybalaam]

Confirming I see that message too.