Source map stack traces

[ehrencrona]

Stack traces on the client side on the dev server are correctly mapped to the source code, but the server-side stack traces are not

In dev mode, if I throw an exception in Nav.svelte, I get this on the server side:

Error: testing stacktrace
    at eval (/_app/components/Nav.js:15:8)
    at Object.$$render (/web_modules/svelte/internal.js:1343:22)

We should map this back to the Nav.svelte file like happens in Sapper.

On a production build, the client-side stack trace from an error I throw in an on:click looks like this:

Uncaught Error: testing stacktraces
    at HTMLButtonElement.<anonymous> (Nav.js:268)
(anonymous) @ Nav.js:268

The server-side stack traces look like:

Error: testing stacktrace
    at fn (/Users/andreasehrencrona/projects/svelte/kit/examples/hn.svelte.dev/.svelte/build/unoptimized/server/_app/components/Nav.js:13:8)

I suppose we should map these too?

[benmccann]

I upgraded to the latest version of source-map and wired in sourcemap_stacktrace in #233. However, it's still not doing anything. I didn't have time to investigate, but would guess one of two things: either the source maps are not available as expected or the stack trace format changed and we need to update the regex in sourcemap_stacktrace to match

[benmccann]

I don't think this is fully working.

In the hn example, I changed the top of src/components/Nav.svelte to:

<script>
	export let section;

	throw Error('test exception');
</script>

The stack trace I get is:

Error: test exception
    at eval (/_components/Nav.js:14:8)
    at Object.$$render (/web_modules/svelte/internal.js:1343:22)
    at eval (/_app/routes/$layout.js:26:61)
    at Object.$$render (/web_modules/svelte/internal.js:1343:22)
    at eval (/_app/assets/generated/root.js:35:50)
    at $$render (/web_modules/svelte/internal.js:1343:22)
    at Object.render (/web_modules/svelte/internal.js:1351:26)
    at get_response (/home/bmccann/src/kit/packages/kit/src/renderer/page.js:184:32)
    at processTicksAndRejections (internal/process/task_queues.js:93:5)
    at render_page (/home/bmccann/src/kit/packages/kit/src/renderer/page.js:270:11)

I'm assuming that first line should say something like Nav.svelte:3:1 instead of Nav.js:14:8

I think that d093806 might have to be reverted (and perhaps also add a call to snowpack.loadUrl #266 (comment))

[Rich-Harris]

Think we can close this now — Vite's sourcemap handling seems pretty robust

[benmccann]

I just tested this and can confirm it does work now that we're on Vite