Astro Info

Astro                    v6.0.4
Vite                     v7.3.1
Node                     v22.19.0
System                   Linux (x64)
Package Manager          pnpm
Output                   static
Adapter                  @astrojs/cloudflare (v13.1.1)
Integrations             none

If this issue only occurs in one browser, which browser is a problem?

No response

Describe the Bug

Using Astro static output with the Cloudflare adapter and Sentry enabled at build time causes Cloudflare's default workerd prerender environment to throw:

TypeError: addEventListener(): useCapture must be false

during prerendering static routes.

Minimal repro setup:

• [email protected]
• @astrojs/[email protected]
• @sentry/[email protected]
• @sentry/[email protected]
• SENTRY_AUTH_TOKEN is set (any non-empty value)
• sentry.client.config.js and sentry.server.config.js call Sentry.init(...)
• Cloudflare adapter uses default prerender environment (workerd)

Observed behavior in repro:

1. SENTRY_AUTH_TOKEN=fake-token pnpm run build
2. Build logs the useCapture must be false stack during prerender
3. Build still finishes as complete
4. dist/client/index.html is empty (0 bytes), indicating broken prerender output

Error stack in repro points into generated .prerender chunk with calls like:

• whenReady
• onTTFB
• instrumentTtfb
• startTrackingWebVitals

What's the expected result?

Cloudflare Workers build should either:

• prerender correctly without runtime errors, producing non-empty HTML, or
• fail hard with a non-zero exit code instead of silently producing empty prerender output.

Link to Minimal Reproducible Example

https://github.com/martinsilha/astro-cloudflare-sentry-prerender-bug

Participation

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