fix: run deferred effects in async components
#16721
Closing issue
Describe the bug
See #16682 (comment)
The issue here is that regular user effects (ones made specifically with $effect, not $effect.pre or render effects) are deferred until the component is mounted. However, since the code that indicates the component as being mounted, $.pop, runs synchronously (even in async components), the effects are never added to the array of deferred effects for their component (and might(?) be added to the parent component if it exists) if they're created after the first top-level await.
Reproduction
Logs
System Info
N/ASeverity
annoyance
Pull request
Closes #16691
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pnpm add https://pkg.pr.new/svelte@16721
Ah cool, thanks for starting that! Somewhat related I investigate various inconsistencies around the first run in #16709 and was thinking to add that on top, since it touches adjacent code paths (the PR already fixes the "properly run attachments and other effects created non-sync" part, but not the top level effects part). But I'll hold off from doing that since this looks promising.
This has been superseded by #16738, closing this.