[bug] page destroyed during hydration if a file fails to load

[benmccann]

Describe the bug

The page from the reproduction loads during SSR and then fails during hydration during dev mode if you both have adblock on and are not using the new experimental.prebundleSvelteLibraries option (RobBrazier/svelte-awesome#775).

This particular example is kind of an edge case, but the outcome is really bad and I'm not so sure how rare it is more generally. Per Rich's point, sometimes things fail to load because you live in NYC and take the subway and lose connectivity going into a tunnel. That the entire page would be wiped out eventhough SSR succeeded is quite a bad outcome. If we wrapped the whole hydration in a try/catch maybe you'd at least see the server-rendered page. Or perhaps if we had error boundaries the developer could do something smarter

Reproduction

https://github.com/benmccann/500-import-failure

Logs

I get a message in the browser:

Failed to fetch dynamically imported module: http://localhost:3000/src/routes/index.svelte

Screenshot:

System Info

This fails on 1.0.0-next.138 and newer all the way up to master since that's when we turned on compilerOptions.hydratable: #2024

https://github.com/sveltejs/kit/blob/master/packages/kit/CHANGELOG.md#100-next138

Severity

blocking all usage of SvelteKit

Additional Information

No response

[Levyks]

I'm having a similar issue, but it's on the client side, I have this component called AdSlot, and it gets blocked if you have an AdBlocker turned on, and, because of that, everything gets broken in my page, the css does not load properly and so on

EDIT: I forgot to mention, the problem only happens when running a production build, with npm run dev it works fine

[codecoded]

I'm having a similar issue, but it's on the client side, I have this component called AdSlot, and it gets blocked if you have an AdBlocker turned on, and, because of that, everything gets broken in my page, the css does not load properly and so on

EDIT: I forgot to mention, the problem only happens when running a production build, with npm run dev it works fine

For reference, looks like my Ghostery is breaking my Sveltekit SPA when in production. 'npm run preview' is ok, and dev. If I host the SPA locally though from the build folder, I can reproduce the issue. Pausing Ghostery and the page hosts fine.

I have one theory, in that I redirect of route based on username of the site like so example.com/username - this redirect uses a branch.io deep link which Ghostery doesn't like

Is there any chance the SPA on hydration hits a URL like example.com/index and causes Ghostery to interject? Why would the behaviour differ from the production build to the npm run preview?

Any ideas on how I can resolve this - just spent 2 days learning SvelteKit and went to deploy for then this to happen :-( Currently I host on firebase hosting but will look at alternatives to see if I can circumvent the issue for now.

[eltigerchino]

Closing this because I can't reproduce this on the latest version of Svelte and SvelteKit with an adblocker on.