Meta: Reliable Storage

[jryans]

Summary

Our storage subsystems can fail out from under us, leading to various kinds of confused application state. This meta issue tracks a set of improvements to move towards something more reliable.

Investigation

See the investigation notes for more detail on how browsers behave today.

Planned Improvements

• Add console logging to record storage state
• Send telemetry about storage consistency
• Improve detection of fallback stores
• Detect case of IndexedDB being deleted and alert user to sign out
• Investigate persistent storage for Electron where we'd like it to default on

Deferred Improvements

• Detect case of Firefox profile storage corruption
• Consider storage estimation to predict issue coming up
• Consider switching to persistent storage to avoid this issue
• Move user's own Olm keys to localStorage, so that they can recover when IndexedDB disappears
• Move more logic inside StorageManager
• Check that IDB stores are the expected version and all object stores are actually created (see also Possible to wedge logs DB if DB exists without object stores #8759)
• Add debug panel in Settings to investigate storage state
• Telemetry attached to UISIs / UTDs (visitor logs with storage state seem good enough for now)

[jryans]

All of improvements we planned to tackle now have been completed. The remaining related items are linked above in the deferred section. I think we can close this issue and use the remaining independent issues going forward.