Errors in the first two lines of server-side endpoints are not reported

[lovasoa]

Describe the bug

When the first line of a server-side endpoint contains an error, the dev server displays TypeError: Line must be greater than or equal to 1, got -1 instead of showing the actual error.

Reproduction

Create a svelte-kit project and paste this in src/routes/server-side.js

/** @type {import('@sveltejs/kit').RequestHandler} */
export async function get({ params }) {
		return {
			body: "Hello world"
		};
}

then start the dev server, load http://localhost:3000/server-route in your browser

Then add a line at the top of the file, containing thisvariableisnotdefined, so as to get

thisvariableisnotdefined

/** @type {import('@sveltejs/kit').RequestHandler} */
export async function get({ params }) {
		return {
			body: "Hello world"
		};
}

Logs

TypeError: Line must be greater than or equal to 1, got -1
    at BasicSourceMapConsumer.SourceMapConsumer_findMapping [as _findMapping] (/tmp/bug3118/node_modules/vite/dist/node/chunks/dep-76613303.js:58876:13)
    at BasicSourceMapConsumer.SourceMapConsumer_originalPositionFor [as originalPositionFor] (/tmp/bug3118/node_modules/vite/dist/node/chunks/dep-76613303.js:58945:22)
    at /tmp/bug3118/node_modules/vite/dist/node/chunks/dep-76613303.js:59886:34
    at String.replace (<anonymous>)
    at /tmp/bug3118/node_modules/vite/dist/node/chunks/dep-76613303.js:59874:21
    at Array.map (<anonymous>)
    at ssrRewriteStacktrace (/tmp/bug3118/node_modules/vite/dist/node/chunks/dep-76613303.js:59873:10)
    at Object.ssrFixStacktrace (/tmp/bug3118/node_modules/vite/dist/node/chunks/dep-76613303.js:60365:36)
    at Object.handle_error (file:///tmp/bug3118/node_modules/@sveltejs/kit/dist/chunks/index.js:4392:15)
    at respond (file:///tmp/bug3118/node_modules/@sveltejs/kit/dist/ssr.js:1841:11)

System Info

System:
    OS: Linux 5.15 Fedora Linux 35 (Workstation Edition)
    CPU: (8) x64 Intel(R) Core(TM) i7-10510U CPU @ 1.80GHz
    Memory: 1.75 GB / 15.28 GB
    Container: Yes
    Shell: 5.1.8 - /bin/bash
  Binaries:
    Node: 16.13.0 - /usr/bin/node
    Yarn: 1.22.10 - /usr/bin/yarn
    npm: 8.1.0 - /usr/bin/npm
  Browsers:
    Firefox: 95.0
  npmPackages:
    @sveltejs/adapter-auto: next => 1.0.0-next.10 
    @sveltejs/kit: next => 1.0.0-next.218 
    svelte: ^3.44.0 => 3.45.0

Severity

annoyance

Additional Information

No response

[benmccann]

Reproduction here: https://github.com/lovasoa/sveltekit-bug-3118

[benmccann]

@lovasoa can you check if this is reproducible with Vite without SvelteKit? I imagine that it would be and should be filed there. See https://github.com/sveltejs/kit#bug-reporting for more details

[Rich-Harris]

This is difficult (not impossible, but difficult) to fix because it's hard to know if a stack trace has already been fixed by Vite. I've opened vitejs/vite#7046

[Rich-Harris]

Should be an easy fix when we next update Vite: vitejs/vite#7048

[lovasoa]

🎉

Thanks @Rich-Harris !