[@cloudflare/vite-plugin] Dev server crashes at startup with `Missing field moduleType` when an Astro 7 project uses @astrojs/vue

[georges-etienne-fortin]

Summary

With Astro 7 + @astrojs/cloudflare 14 (which uses @cloudflare/vite-plugin), astro dev crashes before becoming ready when the project includes the @astrojs/vue integration. The workerd-side runner rejects a module definition:

Missing field `moduleType`
  Stack trace:
    at runInRunnerObject (workers/runner-worker/index.js:107:3)
    at null.<anonymous> (workers/runner-worker/index.js:356:37)

vite build on the same project succeeds; only the dev server is affected.

Versions

• @cloudflare/vite-plugin 1.51.2, miniflare 5.20260804.0-alpha, wrangler 4.120.1
• astro 7.2.0 (bundled vite 8.2.1), @astrojs/cloudflare 14.2.0, @astrojs/vue 7.0.2, @vitejs/plugin-vue 6.0.5 (also reproduced with 6.0.8)
• macOS (darwin 25.3.0), node 24.12.0
• wrangler.toml: nodejs_compat, D1/KV/R2/AI bindings

Reproduction / bisection

Minimal config boots fine:

export default defineConfig({
  output: 'server',
  adapter: cloudflare({ imageService: 'compile', remoteBindings: false }),
});

Adding only the Vue integration reproduces the crash 100% of the time:

export default defineConfig({
  output: 'server',
  integrations: [vue()],
  adapter: cloudflare({ imageService: 'compile', remoteBindings: false }),
});

Not fixed by

• @vitejs/plugin-vue 6.0.8 (latest)
• vite.ssr.noExternal: [/^vue/, /^@vue\//]
• Removing the project's custom main worker entry from wrangler.toml

Timing details (DEBUG=vite:load,vite:resolve)

The crash happens at server creation, during the export-types probe. The last activity before death:

vite:resolve 0.60ms /<project>/index.html -> null
vite:resolve 3.30ms index.html -> null
vite:resolve 0.22ms virtual:cloudflare/export-types -> virtual:cloudflare/export-types
vite:load 2.89ms [plugin] virtual:cloudflare/export-types
Missing field `moduleType`

The error message format (backticked field name) looks like workerd-side deserialization of a module definition that reached the worker loader without a moduleType/type field — plausibly a module served with a MIME type outside the known map once the Vue renderer's module graph is pulled in by the export-types evaluation.

Happy to provide a full repro repository or more debug output if useful.

[workers-devprod]

Note

This is an automated, advisory triage report generated by workers-devprod. It is not an official maintainer response — a maintainer will follow up.

🤖 Automated triage report

Issue Triage: #15129

Summary

astro dev (Astro 7 + @astrojs/cloudflare 14, which uses @cloudflare/vite-plugin) crashes before the dev server is ready with a workerd runner error Missing field \moduleType`whenever the@astrojs/vueintegration is present;vite build` on the same project succeeds.

Classification

• Type: Bug
• Component: packages/vite-plugin-cloudflare
• Severity: High
• Has Reproduction: Yes (minimal config + bisection steps included; no clone-able repo link, but a precise minimal reproduction is described)
• Quality: Complete

Findings

• Created: not reliably extractable from context.json (single-line JSON exceeded the read/grep tooling limit)
• Author: georges-etienne-fortin (Georges-Etienne Fortin)
• Version: @cloudflare/vite-plugin 1.51.2, miniflare 5.20260804.0-alpha, wrangler 4.120.1; astro 7.2.0 (bundled vite 8.2.1), @astrojs/cloudflare 14.2.0, @astrojs/vue 7.0.2, @vitejs/plugin-vue 6.0.5/6.0.8; macOS (darwin 25.3.0), node 24.12.0
• Labels: not reliably extractable from context.json (see note above)
• Comments: not reliably extractable from context.json (see note above)

Analysis

• Component identification: The error originates in the plugin's dev-time module runner (workers/runner-worker/index.js, runInRunnerObject) and is triggered during Vite dev server creation via the virtual:cloudflare/export-types probe. This is squarely in @cloudflare/vite-plugin (packages/vite-plugin-cloudflare), not in Astro or workerd itself. The Missing field \moduleType`error indicates the plugin is sending a module definition to the workerd runner without the requiredmoduleType` field.
• Reproducibility: Reported as 100% reproducible. Clear bisection isolates the trigger to the @astrojs/vue integration — the minimal config without it boots fine, and adding only vue() reproduces the crash. This is strong, actionable evidence even without a hosted repro repo.
• Severity: High — it fully blocks local development (astro dev never becomes ready) for a common Astro + Vue + Cloudflare configuration. Build is unaffected, so it is dev-only, but there is no working dev-server workaround.
• Workarounds ruled out: Reporter already tried @vitejs/plugin-vue 6.0.8, vite.ssr.noExternal: [/^vue/, /^@vue\//], and removing the custom main worker entry — none fix it.
• Not a duplicate/stale/spam candidate: The report is specific, current (alpha miniflare + recent wrangler/vite versions), and contains a real, well-scoped tooling bug. No indication in the available data that it is already fixed or a duplicate.
• Tooling note: context.json is a single very long line; the read tool truncates at 2000 chars and grep only surfaces the line prefix, so labels, comment count, and dates could not be extracted verbatim. The issue body was fully readable and is the basis for this triage.

Recommendation

Status: NEEDS VERIFICATION

Reasoning: This is a well-documented, reproducible dev-only crash in @cloudflare/vite-plugin's module runner, with a clear bisection pointing at how the @astrojs/vue integration's emitted modules are passed to the workerd runner without a moduleType. It should stay open and be verified/fixed; a maintainer should reproduce with the @astrojs/vue integration and inspect where module definitions are built for the runner.

Action: Reproduce locally with Astro 7 + @astrojs/cloudflare 14 + @astrojs/vue, trace the virtual:cloudflare/export-types load path in the plugin's dev module runner, and identify which module definition is missing moduleType (likely a .vue-derived or virtual module) so the plugin can set an appropriate module type. Optionally ask the reporter for a minimal Git repo to speed verification.

Suggested Labels: (omitted — cannot confirm exact repo label strings from the available data; a maintainer should apply the vite-plugin package label and bug label per repo conventions)

Suggested Comment

Thanks for the detailed report and the clean bisection — this is really helpful. The Missing field \moduleType`error is coming from@cloudflare/vite-plugin`'s dev-time module runner, so it's the right place for this issue.

To help us verify and fix it quickly, could you share a minimal Git repository we can clone and run astro dev against (Astro 7 + @astrojs/cloudflare 14 + @astrojs/vue with your minimal config)? That will let us trace exactly which module definition is being sent to the runner without a moduleType. We'll take a look from there.

Structured summary (JSON)

{
  "issueNumber": 15129,
  "title": "astro dev crashes with \"Missing field moduleType\" when @astrojs/vue integration is enabled (@cloudflare/vite-plugin)",
  "githubUrl": "https://github.com/cloudflare/workers-sdk/issues/15129",
  "recommendation": "NEEDS VERIFICATION",
  "difficulty": "medium",
  "reasoning": "Well-documented, 100% reproducible dev-only crash in @cloudflare/vite-plugin's module runner, bisected to the @astrojs/vue integration causing a module definition to be sent to the workerd runner without a moduleType field. It should stay open for verification and a fix.",
  "suggestedAction": "Reproduce with Astro 7 + @astrojs/cloudflare 14 + @astrojs/vue, trace the virtual:cloudflare/export-types load path in the dev module runner, and identify which module definition is missing moduleType; optionally request a minimal Git repo from the reporter.",
  "hasSuggestedComment": true,
  "suggestedLabels": []
}

[workers-devprod]

• Reproduction: ❌ Could not reproduce. I created a minimal Astro 7.2.0 project with @astrojs/cloudflare 14.2.0 (which pulls in @cloudflare/vite-plugin 1.51.2 and miniflare 5.20260804.0-alpha) and @astrojs/vue 7.0.2. After fixing the initial nodejs_compat v1 error by setting compatibility_date = "2024-09-23", running astro dev silently hung for 60 seconds with no output rather than immediately crashing with Missing field moduleType. Attempting to run the dev server in the background then crashed the sandbox execution environment entirely, preventing further testing.

[emily-shen]

Hi, does this happen with the versions @cloudflare/vite-plugin 1.51.1 and wrangler 4.120.0?

If you could provide the full repro repository that would be great.

[georges-etienne-fortin]

@emily-shen Tested with the latest versions today — the crash persists with @cloudflare/vite-plugin 1.51.3 / wrangler 4.120.1 / miniflare 5.20260804.0-alpha (astro 7.2.1, @astrojs/cloudflare 14.2.1, @astrojs/vue 7.0.2, @vitejs/plugin-vue 6.0.8, node 24.12.0, macOS arm64).

Some detail that may explain why the minimal triage repro didn't hit it: in my bisection, the adapter-only config boots fine — the crash requires the @astrojs/vue integration, and the project's wrangler.toml has nodejs_compat plus D1/KV/R2/AI bindings and a custom TS main entry (though removing the custom main didn't help). The last debug trace before death is always: index.html resolving to null (twice), then vite:load [plugin] virtual:cloudflare/export-types, then the workerd-side Missing field `moduleType` .

I'll put together a standalone repro repository next and link it here.

[dario-piotrowicz]

Thanks so much @georges-etienne-fortin a reproduction would indeed be very much appreciated 🙏