Infinite retries with no backoff when homeserver is down but matrix-js-sdk sync has initiated

[770grappenmaker]

Describe the bug

Sable (or most likely matrix-js-sdk) starts spamming the crap out of the homeserver when it responds, but with a non-2xx status, for example with status 502. This is an excerpt of the network tab, all of those requests happen within a fraction of a second.

Reproduction

1. Log in to your homeserver on Sable
2. Have a faulty homeserver, that is, it responds but with for example a 500x status code. I emulated this behavior by adding deny my-ip in my nginx configuration.
3. Reload your client
4. Observe the network tab

Expected behavior

Exponential backoff, or not retrying entirely.

Platform and versions

OS: Linux
Sable: 1.20.0
Browser: Firefox 152
Homeserver: Continuwuity 26.6.2

Additional context

No response

[770grappenmaker]

Might be an upstream issue, and not a Sable issue, I am not sure of that.