Astro Info
Astro v7.0.0-alpha.2
Vite v8.0.16
Node v24.15.0
System macOS (arm64)
Package Manager npm
Output server
Adapter @astrojs/cloudflare (v14.0.0-alpha.1)
Integrations none
If this issue only occurs in one browser, which browser is a problem?
No response (build-time issue)
Describe the Bug
When a page throws during prerendering with the Cloudflare adapter (prerendering runs inside workerd), astro build:
- exits with code 0 and logs
[build] Complete!
- still writes the page to
dist/client, truncated at the exact point of the throw (mid-<head>, no </body>/</html>)
The trigger in the reproduction is the Fonts API: rendering <Font cssVariable="--font-open-sans" /> for a cssVariable that was never registered in fonts throws FontFamilyNotFound — but the underlying problem appears general to any exception thrown during prerendering in the workerd runtime.
Truncated output (full file contents):
<!DOCTYPE html><html lang="en"> <head><meta charset="utf-8"><title>workerd exit code repro</title><!-- --font-open-sans is not registered in astro.config.mjs -> FontFamilyNotFound -->
Whether the error is visible at all is environment-dependent (same versions):
- Linux (
workerd-linux-64, observed in a containerized CI build of a larger project): workerd prints Uncaught exception: ... FontFamilyNotFound: No data was found for the \"--font-open-sans"` family passed to the `` component.` to stderr for every page — but the build still exits 0 and the truncated pages are written.
- macOS (
workerd-darwin-arm64): nothing is printed at all, even with 21 prerendered pages. The error is fully swallowed.
So in CI there is no reliable signal that the build is broken — exit code is 0, and on some platforms the log stream is clean too. Deploying the output produces blank pages.
Switching the page to the registered cssVariable (--font-roboto) produces a complete, correct document, confirming the truncation is caused by the thrown error.
Reproduce:
npm install
npm run build; echo "exit code: $?" # -> exit code: 0, '[build] Complete!'
cat dist/client/index.html # -> truncated mid-<head>
find dist/client -name '*.html' | xargs -I{} sh -c 'tail -c 200 {} | grep -q "</html>" || echo "truncated: {}"'What's the expected result?
A page that throws during prerendering should fail the build with a non-zero exit code (as it does with the Node adapter / non-workerd prerendering), or at minimum the error should be surfaced and the truncated page should not be emitted as if successful.
Link to Minimal Reproducible Example
https://github.com/mikepage/astro-v7-workerd-exit-code
Participation
Astro Info
If this issue only occurs in one browser, which browser is a problem?
No response (build-time issue)
Describe the Bug
When a page throws during prerendering with the Cloudflare adapter (prerendering runs inside workerd),
astro build:[build] Complete!dist/client, truncated at the exact point of the throw (mid-<head>, no</body>/</html>)The trigger in the reproduction is the Fonts API: rendering
<Font cssVariable="--font-open-sans" />for a cssVariable that was never registered infontsthrowsFontFamilyNotFound— but the underlying problem appears general to any exception thrown during prerendering in the workerd runtime.Truncated output (full file contents):
Whether the error is visible at all is environment-dependent (same versions):
workerd-linux-64, observed in a containerized CI build of a larger project): workerd printsUncaught exception: ... FontFamilyNotFound: No data was found for the \"--font-open-sans"` family passed to the `` component.` to stderr for every page — but the build still exits 0 and the truncated pages are written.workerd-darwin-arm64): nothing is printed at all, even with 21 prerendered pages. The error is fully swallowed.So in CI there is no reliable signal that the build is broken — exit code is 0, and on some platforms the log stream is clean too. Deploying the output produces blank pages.
Switching the page to the registered cssVariable (
--font-roboto) produces a complete, correct document, confirming the truncation is caused by the thrown error.Reproduce:
What's the expected result?
A page that throws during prerendering should fail the build with a non-zero exit code (as it does with the Node adapter / non-workerd prerendering), or at minimum the error should be surfaced and the truncated page should not be emitted as if successful.
Link to Minimal Reproducible Example
https://github.com/mikepage/astro-v7-workerd-exit-code
Participation