Bound value on required input sets :invalid state in Firefox

[ellell]

Describe the bug
When binding an empty (undefined or null) value to an input :invalid style state is triggered on initial load in Firefox. It looks like this was fixed in #1233 but seems to be broken again.

To Reproduce
Works in version 3.9.0 REPL
But not in latest version REPL

Information about your Svelte project:
Firefox 78.0.2

Severity
It's a little annoying, I can work around it by not using the required field or simply accepting the red border for now though.

[Glench]

also running into this! although I'm getting it when hydrating with undefined props from SSR.

[danphil]

Still happening on Firefox 86 and Svelte 3.34.0. I've been working around this for a while by resetting the form after mount, as seen in this REPL

Note: this doesn't help with forms that are initially populated on some inputs as the reset will clear the data

Seems to be related to #3569, #4849, etc with commits 081f7cd and d8fb0bb

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[dummdidumm]

I'm not sure what is the issue here, as with latest Chrome/Firefox I see no red borders in the REPL. If I add <style> input:invalid { border: 1px solid red } </style> I see red borders in all browsers for all inputs. Closing for now, but feel free to provide a reproducible that describes the issue better.