[🐞] PrefetchServiceWorker throws `insufficient resources` when navigating while prefetching

[DustinJSilk]

Which component is affected?

Qwik Runtime

Describe the bug

While the PrefetchServiceWorker prefetches the graph, if you interact/navigate to a new page which triggers another prefetch, the browsers throws errors with insufficient resources.

Please see the below video.

https://github.com/QwikDev/qwik/assets/5979984/b38f056e-8baf-48b8-999d-33a63282dfe8

Reproduction

https://github.com/DustinJSilk/qwik-prefetch-nav-crash

Steps to reproduce

$ ./generate.sh

$ pnpm i

$ pnpm preview

Click on the page link before the graph finishes prefetching and see 404s thrown.

System Info

n/a

Additional Information

No response

[gioboa]

How can we solve this issue? @DustinJSilk do you have a possible solution?

[DustinJSilk]

I'm not too clued up on the current implementation, but would this not point to an issue where $maxPrefetchRequests$ isn't being respected, which means the dependencies for the linked page are all being fetched with the highest priority? So the issue here would actually be how the graph is built where all 750 child pages are set as required dependencies for the navigated page to load when they aren't needed yet

[gioboa]

Can you test this version in your environment pls? It works fine for me.

[DustinJSilk]

I'm still getting the same issue mentioned above.

It seems to exist in reverse order as well in a slightly different way, maybe this will help to identify the problem: When first loading the child page, it doesn't prefetch all the symbols yet. Then, when navigating to the home page it prefetches all the symbols in parallel causing the same error as above. I've attached a video below showing this similar issue.

https://github.com/QwikDev/qwik/assets/5979984/d19f32e5-a89f-4327-a129-89c0363dd000

[DustinJSilk]

As I think about it, i wonder if its safe to allow the browser to throw these errors since as long as they eventually recover. We don't know what the limit is per device and don't want to restrict how fast we prefetch if the files are high priority.

So I think the real issue here isn't the fact that the errors are being thrown, they can be ignored, but rather that we're fetching bundles with high priority when they aren't in fact high priority.

[gioboa]

In my PR the dependencies have less priority than the "prefetch" bundles. I think we need to limit the requests in parallel