fix: cleanup resources aggresively on vite-plugin

[anonrig]

An attempt to cleanup resources more aggresively on vite-plugin.

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• Tests
  • Tests included/updated
  • Automated tests not possible - manual testing has been completed as follows:
  • Additional testing not necessary because: impossible to test in an isolated way
• Public documentation
  • Cloudflare docs PR(s):
  • Documentation not necessary because: no user facing change.

A picture of a cute animal (not mandatory, but encouraged)

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[changeset-bot]

🦋 Changeset detected

Latest commit: 334aa84

The changes in this PR will be included in the next version bump.

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[claude]

Claude finished @anonrig's task —— View job

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Changeset Review

Reviewing changeset files...

Tasks:

• Read changeset guidelines
• Validate .changeset/quiet-taxis-rest.md
• Check for cute animal images

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✅ All changesets look good

The changeset .changeset/quiet-taxis-rest.md passes all validation criteria:

• ✅ Version type: patch is appropriate for cleanup/memory improvements
• ✅ Changelog quality: Clear, meaningful description explaining the purpose (cleanup listeners and reduce memory growth)
• ✅ No markdown header violations (no h1/h2/h3 headers used)
• ✅ Not analytics-related
• ✅ Not an experimental feature requiring opt-in notes

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[pkg-pr-new]

create-cloudflare

npm i https://pkg.pr.new/create-cloudflare@12583

@cloudflare/kv-asset-handler

npm i https://pkg.pr.new/@cloudflare/kv-asset-handler@12583

miniflare

npm i https://pkg.pr.new/miniflare@12583

@cloudflare/pages-shared

npm i https://pkg.pr.new/@cloudflare/pages-shared@12583

@cloudflare/unenv-preset

npm i https://pkg.pr.new/@cloudflare/unenv-preset@12583

@cloudflare/vite-plugin

npm i https://pkg.pr.new/@cloudflare/vite-plugin@12583

@cloudflare/vitest-pool-workers

npm i https://pkg.pr.new/@cloudflare/vitest-pool-workers@12583

@cloudflare/workers-editor-shared

npm i https://pkg.pr.new/@cloudflare/workers-editor-shared@12583

@cloudflare/workers-utils

npm i https://pkg.pr.new/@cloudflare/workers-utils@12583

wrangler

npm i https://pkg.pr.new/wrangler@12583

commit: 334aa84

[devin-ai-integration]

Devin Review found 1 new potential issue.

View 14 additional findings in Devin Review.

[devin-ai-integration]

🔴 WebSocket upgrade handler accumulates on each server restart without cleanup

On every Vite dev server restart, configureServer is called again, and handleWebSocket registers a new upgrade handler on the same httpServer (line 174). However, the returned cleanupWebSocket function is only invoked inside httpServer.once("close", ...) (line 179), which only fires when the HTTP server is fully shut down — not on restart. Vite reuses the same HTTP server across restarts.

Root Cause and Impact

The PR correctly introduces cleanup for hotListenerCleanup at the top of the configureServer block (lines 109-110) using a persisted closure variable:

hotListenerCleanup?.();
hotListenerCleanup = undefined;

But no analogous pattern exists for the WebSocket handler. The cleanupWebSocket reference is a local variable inside configureServer and is lost on each subsequent call. After N restarts, there are N active upgrade handlers on the same httpServer, each calling miniflare.dispatchFetch for every incoming WebSocket upgrade request.

Impact: Each WebSocket upgrade request from a client will be processed by all accumulated handlers, potentially causing duplicate connections, wasted resources, and unexpected behavior. This directly undermines the PR's goal of aggressive resource cleanup.

Prompt for agents

In packages/vite-plugin-cloudflare/src/plugins/dev.ts, add a persisted cleanup variable for the WebSocket handler, similar to how hotListenerCleanup is managed. Specifically: 1. Add a `let webSocketCleanup: (() => void) | undefined;` declaration next to `hotListenerCleanup` around line 42. 2. At the beginning of the `if (viteDevServer.httpServer)` block (around line 173), call `webSocketCleanup?.()` to clean up the previous handler before registering a new one. 3. After calling `handleWebSocket(...)` at line 174, store the returned cleanup function: `webSocketCleanup = cleanupWebSocket;`. This mirrors the pattern used for hotListenerCleanup at lines 109-110.

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