chore: simplify source ownership

[Rich-Harris]

I have a feeling we could make this simpler still, by comparing the update_version with the value at the time when the signal was created, but I haven't yet figured out an approach that doesn't result in an additional property on the signal (I thought we could use rv, but it makes it harder to avoid duplicate dependencies).

In the meantime, we don't need to create an object with a reaction property in addition to the sources; as long as we update source_ownership (here renamed to current_sources) when we need to lazily create sources inside proxy.js. Previously we were using set_active_reaction as a way to achieve the same outcome, but in a more roundabout way (normally that function is used so that the effect tree is constructed correctly, but that doesn't apply here).

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Playground

pnpm add https://pkg.pr.new/svelte@16333

[dummdidumm]

This means we keep around an array of sources for longer vs one reaction previously. Hard to say what keeps more memory, I assume it's largely the same, so 👍

[Rich-Harris]

That's true... an alternative would be to prevent push_reaction_sources from running if the child source is being created after the initial reaction. I tried to make that work but it was finicky. If I'd realized we were hanging onto the array for longer with this change I'd have kept plugging away at it

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🦋 Changeset detected

Latest commit: 85e7439

The changes in this PR will be included in the next version bump.

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[Rich-Harris]

Changed the implementation so that current_sources can be GC'd at the end of update_reaction