Rule deprecation request

[marekdedic]

Hi, I'm starting to update my projects to Svelte v5 and noticed that some of the rules I added were no longer relevant or outright incorrect. While at it, I went over all rules and I propose to deprecate the following ones (and eventually remove them once Svelte does so):

• svelte/no-dupe-on-directives - duplicate directives now cause an error in Svelte itself, no need for a lint rule.
• svelte/no-dynamic-slot-name - slots are deprecated and snippets can't have a dynamic name afaik
• svelte/no-reactive-reassign - Reactive statements are deprecated
• svelte/no-immutable-reactive-statements - Reactive statements are deprecated
• svelte/no-reactive-functions - Reactive statements are deprecated
• svelte/no-reactive-literals - Reactive statements are deprecated
• svelte/require-event-dispatcher-types - Events are deprecated
• svelte/experimental-require-slot-types - Slots are deprecated (chore: execute svelte/experimental-require-slot-types only on Svelte 3 and 4 #1005)
• svelte/experimental-require-strict-events - Events are deprecated and the strictEvents attribute is removed outright in Svelte v5
• svelte/no-not-function-handler - Callbacks are regular props in Svelte 5 and thus are checked by TS.

[marekdedic]

Is there some major version planned? (v3 maybe? :D) I could add a PR for this...

[ota-meshi]

We plan to make the next release a major version 👍
Therefore, we plan to make many breaking changes, such as making it ESM-only and droping support for older versions of ESLint, Node, etc.

[baseballyama]

Svelte 5 supports Svelte4 features, therefore I think we can remove these rules in Svelte6 or 7.
But we can remove from recommended rules.
Maybe we need to make a new config for recommended rules of Svelte4?

[marekdedic]

Ok, I'll make a PR. Let's deprecate the rules for now and remove them some time in the future (presumably after Svelte removes the deprecated features).

I think it would be a good idea to review the recommended config for a new major version anyway. (Maybe add some new rules as well?) But I'll remove any deprecated rules from it.

As an aside, I am looking into the three no-reactive-* rules and whether it would make sense to add similar rules for runes. It seems to me that no-reactive-literals and no-reactive-reassign don't make sense, but no-reactive-functions maybe does? I mean, you probably shouldn't define functions in $derived and $effect, right? If so, let's open a new issue for that and track it separately...

[marekdedic]

Actually, infinite-reactive-loop should be included in the list as well!