Child inside the `svelte:head` is not removed from DOM when the parent is unmounted

[tontonsb]

Describe the bug

If the following component is included and subsequently removed, the document head still contains whatever Child is.

<!-- MyComponent.svelte -->
<script>
    import Child from './Child.svelte'
</script>

<svelte:head>
    <Child />
</svelte:head>

I see a lot of similar bugs in this and Kit's issue history, but this still seems present in the latest release.

Reproduction

https://svelte.dev/repl/54395e0587fc49cebf931d11f57f22dc?version=3.55.1

Click the button in the REPL to repeatedly add and remove a Head element, which has the following HTML:

<svelte:head>
	<Title {title} />  <!-- this contains <title>{title}</title> -->
	<meta name="test">
</svelte:head>

You'll see that when Head is added, the title and meta are both added to DOM (inspect it or just look at the counters). When Head is removed the title still remains (but it shouldn't) while meta is correctly cleaned up.

Logs

No response

System Info

Svelte 3.55.1

Severity

annoyance

[tontonsb]

Btw here's a workaround for the repl case. Remove the Title component manually before the Head is removed.

<!-- Head.svelte -->
<script>
	import Title from './Title.svelte'
	import {onDestroy} from 'svelte'
	
	export let title = ''
	
	let enabled = true
	onDestroy(() => enabled = false)
</script>

<svelte:head>
	{#if enabled}
	<Title {title} />
	{/if}
	<meta name="test">
</svelte:head>

Trying the same cleanup inside Title doesn't seem to help, even though onDestroy is called.

[dummdidumm]

Closing as duplicate of #7656

[tontonsb]

@dummdidumm it's not a duplicate, it was another issue.

This issue was about child components inside head. They are never removed, reinserting the component duplicates the contents of the component (and makes additional copy of contents on every reinsert) and it doesn't matter if you put a title tag or anything else in the Title.svelte component here: https://svelte.dev/repl/54395e0587fc49cebf931d11f57f22dc?version=3.55.1

However, the issue has been fixed in Svelte 5: https://svelte.dev/playground/54395e0587fc49cebf931d11f57f22dc?version=5.1.3

So it is still probably fine to close this.

The #7656 issue on the other hand is some quirk related to title behaving differently than meta. But it doesn't make additional copies of title, it just leaves it in when it should be removed. And that problem appears to persist in Svelte 5: https://svelte.dev/playground/2ecf81b43d0d4b2eaa02d80adf803929?version=5.1.3

[dummdidumm]

Thanks for the explanation, and sorry for the confusion. Keeping this closed because as you say it's fixed in Svelte 5