`preact-cli` isn't able to SSR if the app uses `@preact/signals`

Just started to use signals in an app I created using preact-cli, but now the SSR breaks with the following error:

❯ npm run build

> my-project@0.0.0 build
> preact build

 Build  [==================  ] 92% (4.8s) chunk asset optimizationUnable to read file: /Users/rakesh.pai/code/my-project/src/src/index.ts

TypeError: Cannot read properties of null (reading '_u')
Cannot determine error position. This most likely means it originated in node_modules.

This could be caused by using DOM or Web APIs.
Pre-render runs in node and has no access to globals available in browsers.

Consider wrapping code producing error in: "if (typeof window !== "undefined") { ... }"

Alternatively use "preact build --no-prerender" to disable prerendering.

See https://github.com/preactjs/preact-cli#pre-rendering for further information.

This error message itself isn’t very useful (and I don’t know why there’s an additional /src in the file path), but this error doesn’t occur and the build runs successfully if I remove signals.

The usage of signals is very minimal:

import { computed, signal } from '@preact/signals';

const currentState = signal('idle');

const isFormEnabled = computed(() => currentState.value !== 'loading');

const SomeComponent = () => (
  <form>
    <input type="text" disabled={!isFormEnabled.value} />
  </form>
)

Am I doing something wrong?

[marvinhagemeister]

Fixed by #198

[rschristian]

This error message itself isn’t very useful (and I don’t know why there’s an additional /src in the file path)

Sorry about that. Getting useful stack traces out of content built with Webpack has always been rather difficult, though I do spot a couple obvious issues and will try to spend some time on that.

The actual error position is in ../src/index.ts. Our error message incorrectly assumes it’s in your source code, and so prepends /Users/rakesh.pai/code/my-project/src/, hence the double src.

Not sure what the actual issue is, just speaking to the error message itself at the moment.