Note that autosave will only trigger for already-persisted association records if the records themselves have been changed. This is to protect against SystemStackError caused by circular association validations.

The <svelte:self> element allows a component to include itself, recursively. It cannot appear at the top level of your markup; it must be inside an if or each block to prevent an infinite loop.

I don't know what I'd expect this to do, if not create an infinite loop. You're asking Svelte to do something before every update, and one of the things you're asking it to do is to flush any pending changes and trigger an update.

I think the bind:this={things[f.name]} invalidates f (perhaps erroneously?) which then invalidates foo, which causes the infinite loop.