🐛 BUG: Error when building Just the Basics starter : Cannot read properties of undefined (reading 'icon')

[florian-s-code]

What version of astro are you using?

v1.0.0-beta.36

Are you using an SSR adapter? If so, which one?

None

What package manager are you using?

npm

What operating system are you using?

Linux

Describe the Bug

The build of "Just the basics" starter fails with the error : Cannot read properties of undefined (reading 'icon')
We have got 2 reports through Discord and I have been able to reproduce it.

Dev mode works, only the build fails.

Reproduction steps:

1. Run npm init astro
2. Choose "Just the basics" and default options (no integrations)
3. Run npm run build

❯ npm run build --verbose
[...]

> @example/basics@0.0.1 build
> astro build

11:15:20 [build] Collecting build information...ed in 27ms
11:15:21 [build] Completed in 516ms.load Completed in 27ms
11:15:21 [build] Building entrypoints for prerendering...
(!) Could not auto-determine entry point from rollupOptions or html files and there are no explicit optimizeDeps.include patterns. Skipping dependency pre-bundling.
11:15:21 [build] Completed in 452ms.load Completed in 27ms

 generating static routes 
▶ src/pages/index.astro
 error   Cannot read properties of undefined (reading 'icon')
    at file:///tmp/tmp.SrDkX4sUEP/test/dist/entry.mjs?time=1653902121795:84:21
    at ft (file:///tmp/tmp.SrDkX4sUEP/test/dist/entry.mjs?time=1653902121795:66:398)
    at w (file:///tmp/tmp.SrDkX4sUEP/test/dist/entry.mjs?time=1653902121795:39:4033)
npm timing command:run Completed in 2513ms
npm verb exit 1
npm timing npm Completed in 2646ms
npm verb code 1

Link to Minimal Reproducible Example

https://stackblitz.com/github/withastro/astro/tree/latest/examples/basics

Participation

• I am willing to submit a pull request for this issue.

[florian-s-code]

I have proposed a quick fix for this specific theme so that people starting with create-astro and the "Just the basics" starter are not let down by a bug on their first build.

It seems to be a structural bug with named slots, that break the build if no content is passed. A better fix is needed.

[sarah11918]

I merged #3475 to implement a quick fix, so that the starter builds, but leaving this issue OPEN for @bholmesdev or anyone who wants to implement a different solution.

[bholmesdev]

Looks good, thanks for catching this! Happy to close 👍

[natemoo-re]

Reopening this since the underlying bug is still a problem. I'm looking into it.

[matthewp]

We have a default parameter we use internally for children, something like function render(.., children = {}) and that is being tree-shaken away. I'm pretty sure it's this Rollup change causing it: rollup/rollup#4498

It was reverted today: rollup/rollup#4520

So going to try again and see if the problem goes away.