RenderUndefinedEntryError from dev server

[andersk]

What version of starlight are you using?

0.30.2

What version of astro are you using?

5.0.9

What package manager are you using?

npm

What operating system are you using?

Linux

What browser are you using?

Chromium, Firefox

Describe the Bug

The official StackBlitz template linked from getting started shows an error page:

RenderUndefinedEntryError

Attempted to render an undefined content collection entry.

See Docs Reference
Check if the entry is undefined before passing it to render()

errors/errors.js:16:5

…
    if (message) this.message = message;
    ^
…

Stack Trace

RenderUndefinedEntryError
    at new AstroError (/home/projects/kkvilwbjno.github/node_modules/astro/dist/core/errors/errors.js:16:5)
    at renderEntry (/home/projects/kkvilwbjno.github/node_modules/astro/dist/content/runtime.js:345:11)
    at eval (/home/projects/kkvilwbjno.github/node_modules/@astrojs/starlight/routes/common.astro:18:71)
    at AstroComponentInstance.common (/home/projects/kkvilwbjno.github/node_modules/astro/dist/runtime/server/astro-component.js:19:12)
    at AstroComponentInstance.init (/home/projects/kkvilwbjno.github/node_modules/astro/dist/runtime/server/render/astro/instance.js:38:29)
    at bufferHeadContent (file:///home/projects/kkvilwbjno.github/node_modules/astro/dist/runtime/server/render/astro/render.js:142:37)
    at Module.renderToAsyncIterable (file:///home/projects/kkvilwbjno.github/node_modules/astro/dist/runtime/server/render/astro/render.js:159:11)
    at async Module.renderPage (file:///home/projects/kkvilwbjno.github/node_modules/astro/dist/runtime/server/render/page.js:46:24)
    at async lastNext (file:///home/projects/kkvilwbjno.github/node_modules/astro/dist/core/render-context.js:179:25)
    at async eval (file:///home/projects/kkvilwbjno.github/node_modules/astro/dist/i18n/middleware.js:64:22)

and the following console output:

❯ npm install && npm run dev

added 417 packages in 11s

206 packages are looking for funding
  run `npm fund` for details

> @example/[email protected] dev
> astro dev

12:38:54 [types] Generated 4ms

 astro  v5.0.9 ready in 8118 ms

┃ Local    http://localhost:4321/
┃ Network  use --host to expose

The collection "docs" does not exist or is empty. Ensure a collection directory with this name exists.
12:39:00 [content] Syncing content
12:39:00 [content] Content config changed
12:39:00 [content] Astro version changed
12:39:00 [content] Clearing content store
12:39:00 [content] Synced content
12:39:00 watching for file changes...
12:39:04 [ERROR] [RenderUndefinedEntryError] 
  Hint:
    Check if the entry is undefined before passing it to `render()`
  Error reference:
    https://docs.astro.build/en/reference/errors/render-undefined-entry-error/
  Stack trace:
    at /home/projects/kkvilwbjno.github/node_modules/astro/dist/core/errors/errors.js:16:5
    [...] See full stack trace in the browser, or rerun with --verbose.

Link to Minimal Reproducible Example

https://stackblitz.com/github/withastro/starlight/tree/main/examples/basics

Participation

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

[delucis]

Thanks for the issue @andersk. I’ve also been seeing this intermittently. It seems there are some race conditions in content collection loading that can lead to this.

A workaround is to type s and then enter in the dev server terminal to force refresh content, but obviously this is not a very pleasant dev experience.

I’m going to transfer this to the main Astro monorepo as it will need addressing there I believe.

[techfg]

I've encountered this issue in several projects in Stackblitz and locally. In all cases, running npm install again and/or npm run astro sync seems to resolve the issue. However, in a project I just attempted to upgrade from 4 to 5, nothing seems to resolve the issue and I'm unable to get past it. I've tried sync, force, etc. and continue to encounter the The collection "docs" does not exist or is empty. Ensure a collection directory with this name exists. error along with RenderUndefinedEntryError.

Couple of additional notes:

1. Astro 5.1.1 & Starlight 0.30.3
2. The site is in a subdirectory from root (./site) which is different than the other projects I've encountered this issue with
3. The site has a base which is different than other projects I've encountered this issue with
4. using legacy: { collections: true } does not encounter the issue

Are there any other potential workarounds until this is addressed?

EDIT: Was finally able to get it to work, just kept deleting ./astro, ./node_modules, running sync, force over and over until it finally worked when running dev.

[ascorbic]

Is this just occurring on Linux, or is anyone experiencing it on other platforms?

[oluwatobiss]

I'm experiencing the same on Windows.

[techfg]

Just tested that same site on windows. I got the The collection "docs" does not exist or is empty. Ensure a collection directory with this name exists. error but the site rendered and I didn't get the RenderUndefinedEntryError error.

Limited testing, obviously, but I think the underlying issue is not platform specific from best I can tell and @oluwatobiss confirmed as much I believe.

[ascorbic]

If you'd like to try an experimental build that should fix it, install astro@experimental--dev-after-sync

[andersk]

Yeah the experimental--dev-after-sync build from #12818 seems to work in my project.

[techfg]

Seems to be a race condition that causes this so difficult to say for certain if astro@experimental--dev-after-sync fully resolves the issue but I tried several attempts running from a "clean" state and haven't been able to reproduce the issue when using it. Looking good, thank you!

[Princesseuh]

Fixing this will probably also fix #12456