suggestion: Allow for configuration of the maximum number of queued effects before infinite_loop_guard() is called.

[michaelthoreau]

I ran into an issue with a mapping project where a large number of components (thousands) are affected by an effect (infrequently).

It would be great to be able to increase the number of queued effects before the infinite loop guard comes in to effect (pun intended):

Currently:

if (flush_count++ > 1000) {
	// other code

	infinite_loop_guard();
}

svelte/packages/svelte/src/internal/client/reactivity/batch.js

Line 519 in f0cede6

if (flush_count++ > 1000) {

[Rich-Harris]

Uhhhhh can you repro this? It's fine to have thousands of effects in thousands of components, as long as those effects don't cause other effects to run, which cause other effects to run, until you've gone around the merry-go-round a thousand times.

It's hard for me to imagine a working app in which effects can trigger each other that many times, so I'm left wondering if there's a bug somewhere. One effect causing a state change that triggers another effect is an anti-pattern, two is tech debt, three is cause for alarm. More than a thousand... that is seriously outside the bounds of expected usage so I'm very curious to see it!

[michaelthoreau]

uhhhh, it was most likely just a bug on my end, though i'm not 100% sure.

I produced an example that is very similar, which does crash when the effect is used in a way that is similar to my more complex setup:
https://svelte.dev/playground/ee24ea9ad27c4a91bdb598a9e89e95cd?version=5.39.6

I'm unsure if this is actually related to the maximum effect depth, as i'm actually not sure what is causing this to crash (browser tab freezes entirely). I may just be doing something else silly here.

TL;DR Probably a bug that i introduced.

[Rich-Harris]

i'm going to reopen this, just so we can one day get to the bottom of this — it looks like there's something disrupting the counter when a component is programmatically mounted inside a component, which isn't super common but which should definitely work