Invalid `svelte:element`s are not caught by `svelte:boundary` during SSR

[WarningImHack3r]

Describe the bug

Rendering errors caused by invalid tags passed to <svelte:elements are not caught by the nearest <svelte:boundary> during SSR. They work fine on the client during CSR, but trigger a 500 on the server.

As boundaries now work on the server since 5.53.0, I was expecting this kind of error to be also caught. I don't know if there are other rendering errors that are also in this situation, or if invalid tags if the only rendering error that isn't properly caught

Invalid tags errors are correctly caught by the handleError hook inside hooks.server.ts, though.

Reproduction

SvelteLab

While it works when changing the element tag on the fly via the input field, refreshing the page with an invalid name hardcoded as the initial value of the $state triggers a 500

Logs

[500] GET /
Svelte error: dynamic_element_invalid_tag
`<svelte:element this="invalid_name">` is not a valid element name — the element will not be rendered
https://svelte.dev/e/dynamic_element_invalid_tag
    at Module.dynamic_element_invalid_tag (node_modules/svelte/src/internal/server/errors.js:47:16)
    at Module.element (node_modules/svelte/src/internal/server/index.js:93:27)
    at eval (src/lib/Counter.svelte:23:26)
    at Renderer.child (node_modules/svelte/src/internal/server/renderer.js:218:18)
    at Renderer.component (node_modules/svelte/src/internal/server/renderer.js:323:22)
    at Counter (src/lib/Counter.svelte:11:13)
    at eval (src/routes/+page.svelte:25:39)
    at Renderer.boundary (node_modules/svelte/src/internal/server/renderer.js:270:19)
    at eval (src/routes/+page.svelte:21:15)

System Info

SvelteLab

Severity

annoyance

[dummdidumm]

SvelteKit doesn't make use of the error boundary SSR capability yet, pending PR: sveltejs/kit#15308. Closing in the meantime, will be merged soon