fix: set deriveds as CLEAN if they are assigned to

[paoloricciuti]

Closes #15590

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Preview: https://svelte-dev-git-preview-svelte-15592-svelte.vercel.app/

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Playground

pnpm add https://pkg.pr.new/svelte@15592

[trueadm]

If the derived is unowned then it might not be safe to mark it as clean, but rather maybe dirty.

[paoloricciuti]

If the derived is unowned then it might not be safe to mark it as clean, but rather maybe dirty.

Gotcha, will see if it works in a bit...can you help me come up with a test that actually test the problematic situation (the test I wrote is using unowned deriveds no?)

[paoloricciuti]

Oh wait this has a bug

[paoloricciuti]

Mmm this is more complex than i thought: if we reassign before the first read then the derived is not a reaction of the state and it will not be updated when the state changes 🤔

[paoloricciuti]

@trueadm this fixes the bug i was talking about but it introduce a new constant and basically execute the derived without assigning the value and the status in the case where the derived is clean because it was assigned to (basically it's just to still register the dependency).

I couldn't come up with a better idea but i wonder if there's one.