Vite dependency optimization re-evaluates server modules during in-flight requests

[TorbjornHoltmon]

Astro Info

Astro                    v7.3.5
Node                     v24.19.0
System                   macOS (arm64)
Package Manager          pnpm
Output                   server
Adapter                  @astrojs/cloudflare
Integrations             none

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

No response

Describe the Bug

After switching from astro 5 to workers and astro 7, we started seeing a lot of issues with local development and optimize deps.
This is one of the issues we have been able to reliably reproduce so far.

During development, Vite can discover and optimize a new dependency while a server request is already being processed. This can happen with a dynamic import or when calling an Astro action directly from an .astro file.

The request then spans two module generations.
In the reproduction, middleware stores a request ID using AsyncLocalStorage. After dependency optimization reloads the server, later code sees a new module instance and the request context is lost.

The reproduction also demonstrates the same behavior with a plain exported object: a value stored by middleware is missing after optimization. This shows that the issue is caused by module re-evaluation, not AsyncLocalStorage itself.

We are seeing this specifically when using the Cloudflare plugin.

What's the expected result?

Any context or in-memory state set before optimization should still be available afterward.

Link to Minimal Reproducible Example

https://github.com/TorbjornHoltmon/vite-cloudflare-optimize-deps-repro

Participation

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

[astro-factory]

Triage complete

• Prepare the workspace: ready
• Install dependencies: complete
• Build the project: complete
• Reproduce the issue: confirmed
• Diagnose the cause: high confidence
• Verify the diagnosis: bug
• Attempt a fix: verified
• Publish the result: set triage: fix pending

---

• Reproduced: Yes — all three routes (/, /object, /dynamic) confirmed broken with Cloudflare adapter dev mode
• Exploration: Yes — View branch
• Unit Test: Yes — packages/astro/test/units/vite-plugin-environment/server-entries.test.ts
• Priority: P4: important. This breaks any Cloudflare dev project where a user dependency is imported from a .ts/.js file (actions, middleware, utilities) and hasn't been cached yet — a common cold-start scenario.

The root cause is in packages/astro/src/vite-plugin-environment/index.ts. The optimizeDeps.entries glob for server environments (active when @cloudflare/vite-plugin sets noDiscovery: false) was **/*.{jsx,tsx,vue,svelte,html,astro,mdx} — missing .ts and .js. This means Vite's dep scanner never reaches plain TypeScript modules like src/actions/index.ts during the initial scan. When a user dependency (e.g. dedent) is first imported at request time, Vite discovers and optimizes it mid-request, triggering a full-reload in workerd that clears all evaluated modules and breaks in-flight AsyncLocalStorage context and module-level state.

I found a potential fix for this issue. The fix adds .ts and .js to the server-side entries glob so Vite's dep scanner discovers npm imports from actions, middleware, and other TypeScript modules up front, avoiding mid-request re-optimization. This is the same pattern as #17929 (added .astro) and #17953 (added .mdx).

Try this fix

You can test this fix right now without waiting for a release:

# astro
npm i https://pkg.pr.new/astro@88928db

If this fixes your issue, please leave a comment letting us know (for example
"confirmed, this fixes it"). A pull request will then be opened to get it merged.

Full Triage Report

Reproduction

Cloned the provided reproduction repo and confirmed the bug on all three routes:

• / route: Error: AsyncLocalStorage request context was lost — middleware sets AsyncLocalStorage context, then the action imports dedent (triggers optimization), and the context is lost after workerd reloads modules.
• /object route: Shows After optimization: undefined — module-level object state set by middleware is wiped after reload.
• /dynamic route: Same as / but triggered via dynamic import().

Server logs show the sequence: dependency optimized: dedent → optimized dependencies changed. reloading → program reload → error.

Root Cause

In packages/astro/src/vite-plugin-environment/index.ts (line ~83), the optimizeDeps.entries glob for server environments is:

src/**/*.{jsx,tsx,vue,svelte,html,astro,mdx}

This covers component file formats but not .ts/.js. When the Cloudflare adapter enables dependency discovery (noDiscovery: false), Vite scans these entry files to discover npm imports up front. Since .ts files like src/actions/index.ts are not scanned, their imports (e.g. dedent) are only discovered at runtime, triggering a full module reload in workerd.

The entries glob has been expanded incrementally as this class of bug was encountered:

• Environment API (commit 141c4a264): {jsx,tsx,vue,svelte,html,astro}
• astro dev returns 504 "Outdated Optimize Dep" for the dev-toolbar entrypoint when a linked package pulls in a late-discovered dependency #17929: Added .astro to client entries
• Preserve Vite module IDs through content asset propagation to fix CSS HMR after ClientRouter navigation #17953: Added .mdx to both environments

Adding .ts and .js is the natural next step — plain TypeScript modules (actions, middleware, utilities, API routes) are common on the server side and may import npm packages.

Fix

--- a/packages/astro/src/vite-plugin-environment/index.ts
+++ b/packages/astro/src/vite-plugin-environment/index.ts
@@ -80,7 +80,11 @@
 				if (_options.optimizeDeps?.noDiscovery === false) {
 					finalEnvironmentOptions.optimizeDeps = {
-						entries: [`${srcDirPattern}**/*.{jsx,tsx,vue,svelte,html,astro,mdx}`],
+						// Server-side code lives in .ts/.js files (actions, middleware,
+						// utilities) as well as component formats. Include them so the
+						// dep scanner discovers npm imports up front and avoids a
+						// mid-request re-optimization that would reload workerd modules.
+						entries: [`${srcDirPattern}**/*.{ts,js,jsx,tsx,vue,svelte,html,astro,mdx}`],
 						include: [],
 						exclude: ['node-fetch'],
 					};

Verification

With the fix applied, all three routes return 200 with correct UUIDs. Server logs show no dependency optimized: dedent or optimized dependencies changed. reloading messages — dedent is discovered during the initial scan.

Unit Test

Added packages/astro/test/units/vite-plugin-environment/server-entries.test.ts with two tests:

1. Verifies .ts and .js are included in server entries when noDiscovery is false
2. Verifies no entries are set when noDiscovery is not explicitly false

Regression Check

Full unit test suite: 3552 pass, 2 fail (pre-existing failures in test/units/assets/fonts/e2e.test.ts, unrelated).

This report was made by an LLM. The analysis may be wrong, and the potential fix might not work, but is intended as a starting point for exploring the issue.

[TorbjornHoltmon]

While this fix does fix the problem inside the repro. When we try to test this fix in our projects, we have so many different vite/cloudflare-vite/astro issues overlapping right now, that it is very hard to confidently say that this fix solved everything for us.

See #18132 for an additional issue that we are currently experiencing with astro/vite/cloudlare-vite.

What I can say, is that this fix does not fix #18132

[astro-factory]

The fix has been verified! A pull request has been created: #18133