Svelte 5: `$effect.pre()` callable without error outside of component initialisation

[robertadamsonsmith]

Describe the bug

$effect.pre() can be called outside of component initialisation without error, unlike $effect().

This is not documented behaviour, and is possibly not intended.

(Arguably it is useful that $effect.pre() can be called asynchronously in this way, and relates to the more general issue raised here: #9265)

Reproduction

https://svelte-5-preview.vercel.app/#H4sIAAAAAAAACkVPu2rEMBD8FSGu8D3IPUrHNqRMny5OcZbHIE4vpFUgCP175FOCu52ZnZndxBepEHj7mbi5a_CWvznHT5x-3ArCNxSh4GCjFyvTBeGlo2E0IykQM1FP8Kxnu0B3QnPdv_5Ls42Twrxpm0QI9AQB9CE1bKSm2fdDWrmRdlgWCHpxHk96S6p1h1uNyqfr5VJGGk133g4z3RSJrGHWtEJJ8ejTmlK9x2Me3o3w0DDUnetmcaUqZ3Zgt1KU_jpzeV7bWS4SM2_JR-Sv_AvW9s7bNwEAAA==

Logs

No response

System Info

https://svelte-5-preview.vercel.app/

Severity

annoyance

[aradalvand]

Arguably it is useful that $effect.pre() can be called asynchronously in this way

I'd like to emphasize this part. If both $effect and $effect.pre are only callable during component initialization, this means effects would be too limiting and many interesting scenarios won't be possible.
Dominic mentioned on Discord that he is thinking about this very issue, acknowledging the problem.