prerender when using hooks.server.js

[coryvirok]

Describe the bug

I'm not sure if this is a bug or not but I was confused by it so maybe we need a docs update.

The issue is that even though +layout.js exports export const prerender = false the build step will invoke hooks.server.js with the URL. If there is logic in the hooks.server.js#handle() function that is not prerenderable, (e.g. accessing event.url.search) the build will fail.

I assumed that since the layout disabled prerendering for its page tree, handle() would not even be invoked.

I think it's pretty common to have non-prerenderable code in hooks.server.js. In my case, I check auth and then redirect to /login?next=PATH_AND_SEARCH_OF_ORIGINAL_URL which breaks prerender.

The workaround is to check building in hooks.server.js before doing anything non-prerenderable. This probably deserves a mention in the docs since handle() will be invoked even for non-prerenderable URLs.

Reproduction

https://stackblitz.com/edit/sveltejs-kit-template-default-dapyhy?file=src/hooks.server.js

Run npm run build

Logs

No response

System Info

System:
    OS: Linux 5.0 undefined
    CPU: (2) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
    Memory: 0 Bytes / 0 Bytes
    Shell: 1.0 - /bin/jsh
  Binaries:
    Node: 16.14.2 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 7.17.0 - /usr/local/bin/npm
  npmPackages:
    @sveltejs/adapter-node: latest => 1.2.4 
    @sveltejs/kit: ^1.5.0 => 1.17.0 
    svelte: ^3.54.0 => 3.59.1 
    vite: ^4.3.0 => 4.3.7

Severity

serious, but I can work around it

Additional Information

No response

[elliott-with-the-longest-name-on-github]

FWIW I ran into this issue waaaaay back in like v250 of the beta (back when building was prerendering or something) and had the same confusing experience. I'm not sure what the best way to communicate this is, but I definitely felt the pain.