`applyAction` should navigate to action if action is different from current route

[paoloricciuti]

Describe the bug

If a form has an action to another route and you use enhance as per doc it doesn't automatically navigate to the new route.

But from the doc it seems like using applyAction should apply the default browser behavior.

This doesn't seem to be the case: the action gets called but the routing doesn't happen.

Reproduction

1. Go to https://www.sveltelab.dev/j9dffhs0vu1rqub
2. Try to submit the form
3. Observe that the navigation doesn't happen
4. Try to remove the use:enhance
5. Submit the form
6. Observe that the browser correctly redirect there

Logs

No response

System Info

System:  OS: Linux 5.0 undefined CPU: (8) x64 Intel(R) Core(TM) i9-9880 H 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-auto: "2.0.0 => 2.1. 
0 
@sveltejs/kit: "1.5.0 => 1.18.0 svelte: "3.54.0 => 3.59.1 vite: "4.1.4 => 4.3.8

Severity

serious, but I can work around it

Additional Information

To be clear this is only present when the action return a success, not when it return a redirect

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

Confirmed behavior is as reported -- looks like a 🐛

[dummdidumm]

This is not a bug, it's expected behavior. If you have a form on page X that references actions on page Y you don't navigate there on success. That allows you to implement things like a newsletter signup inside a +layout.svelte which is present on all pages and where you can handle the success message/errors on the page you're currently on, not losing context. It should probably made clearer in the docs.

[paoloricciuti]

Shouldn't this behavior be already covered by not calling applyAction? I feel like applyAction should have the same behavior of a non enhanced form

[dummdidumm]

No, because applyAction ensures the form prop is updated which is crucial for error messages etc and sometimes for success cases, too.

[paoloricciuti]

So the actual recommended way is to manually goto?

[paoloricciuti]

Actually now that I think about it manually goto is not an option if you want to use the form object in the new page right?

[dummdidumm]

You could pass a query string or save things in a cookie, or put it in event.locals

At this point I'm wondering why the form is even on another page at all, what's the use case?

[paoloricciuti]

It was for helping a folk in the svelte discord...he wanted to do something with the form data and than show a recap in the /rec page ..it seems a pretty reasonable use case honestly and given that's how the platform usually behave it doesn't seem wrong to thing you could do this. But I get the reasoning. Maybe it could be an option on applyAction?

Again, it's not something that I need...is just something that seemed off to me, totally ok if you prefer to leave it like this

[dummdidumm]

Honestly I think it's the wrong solution to (ab)use the fact that you're redirected to the /rec page in the native case. What about error handling? That would also happen on /rec then which is not what this page is about. local.recap = ..; throw redirect('/rec'); within the action sounds like a better solution to me.

[paoloricciuti]

Again it's not a matter of what's better...I would probably do something like this myself if that's something that I would need. It was only a fact of being completely different from the platform.

That's it.