[vite-plugin] vite build never exits when remoteBindings is enabled — remote proxy session is never disposed

[alexander-zuev]

With remoteBindings enabled, vite build produces all output correctly and then hangs forever. The process never exits.

Environment

• @cloudflare/vite-plugin@1.51.1
• wrangler@4.120.0
• vite@8.2.1
• TanStack Start, prerendering enabled
• Worker has 7 Durable Object bindings and D1/KV/VPC bindings with "remote": true

Reproduction

Run a build with remoteBindings: true in the plugin options and prerendering enabled.

The remote connection is established fine (no error 10375, so #13956 is genuinely fixed — thank you). The prerender pass completes:

⎔ Establishing remote connection...
[prerender] Prerendering pages...
[prerender] Crawling: /
GET / 200 OK (89ms)
...
[prerender] Prerendered 117 pages:

Every file is written to dist/, the output is correct, and then the process just sits there. It has to be killed manually.

Cause

startRemoteProxySession in wrangler creates a full DevEnv with a listening server:

const workerConfig = {
  name: options.workerName ?? crypto2.randomUUID(),
  entrypointSource: ProxyServerWorker_default,
  ...
  server: { port: 0, secure: false }
};
let devEnv;
try {
  devEnv = new DevEnv(workerConfig);
  devEnv.start();
}

That listening server is a referenced libuv handle, so Node's event loop cannot drain while it stays open.

On the plugin side, sessions are kept in a module-level map:

/** Map that maps worker configPaths to their existing remote proxy session data (if any) */
const remoteProxySessionsDataMap = new Map();

Grepping the built plugin (dist/index.mjs of 1.51.1), that map has 2 gets and 2 sets (one pair on the dev server path, one on the preview server path) and zero deletes. The only session.dispose() call in the whole bundle is:

if (!authSameAsBefore) {
  if (preExistingRemoteProxySessionData?.session)
    await preExistingRemoteProxySessionData.session.dispose();
  remoteProxySession = await startSession(remoteBindings, { ... });
}

It only fires to replace a session when auth changes. There is no teardown when the preview server closes or when the build ends.

For vite dev this is invisible, since the server runs until you interrupt it. For vite build, the preview server exists only to serve the prerender pass, so once the pass finishes nothing disposes the session and the build hangs.

Expected

The preview server's remote proxy session should be disposed when the build completes, so vite build exits normally.

Impact

Remote bindings cannot be used in any CI build. That rules out prerendering pages against real data, which is otherwise exactly what remote bindings make possible. In our case the prerendered output was perfect (real values from D1 dehydrated into the static HTML) and the only thing standing in the way is the process not exiting.

I could not find an existing issue for this, and the 1.52.0 changelog does not appear to touch session disposal or build exit.

[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: #15173

Summary

vite build never exits when remoteBindings is enabled — the remote proxy session (which holds an open, referenced libuv server handle) is never disposed after the prerender/preview pass completes.

Classification

• Type: Bug
• Component: packages/vite-plugin-cloudflare (with a root cause in packages/wrangler's startRemoteProxySession)
• Severity: High
• Has Reproduction: Yes (clear steps + detailed root-cause analysis; no clone-able repo, but steps are specific)
• Quality: Complete

Findings

• Created: 2026-08-13
• Author: alexander-zuev
• Version: @cloudflare/vite-plugin@1.51.1, wrangler@4.120.0, vite@8.2.1 (TanStack Start, prerendering enabled)
• Labels: none
• Comments: 0

Analysis

• Component is clearly the Vite plugin. The reporter identifies remoteProxySessionsDataMap (a module-level Map in the plugin's built dist/index.mjs) as having get/set calls but zero deletes, and only one session.dispose() call which fires only to replace a session when auth changes — never as teardown on preview-server close or build completion.
• Root cause is well-traced into wrangler. startRemoteProxySession creates a full DevEnv with a listening server (server: { port: 0, secure: false }). That listening server is a referenced libuv handle, so Node's event loop can't drain while it stays open — this is why vite build hangs while vite dev looks fine (dev server runs until interrupted anyway).
• High severity / clear scope. Affects any use of remote bindings during vite build — i.e. all CI builds, and specifically the prerender-against-real-data use case that remote bindings are meant to enable. Output is correct; only process exit is broken.
• No workaround noted other than manually killing the process, which is unusable in CI.
• Not a duplicate / not stale. Reporter checked for an existing issue and reviewed the 1.52.0 changelog (no session-disposal or build-exit changes). Issue is brand new (created same day, no activity yet). The reporter confirms [vite-plugin] Remote-bindings proxy upload rejected with code 10375 when worker has Durable Object bindings #13956 is fixed, so this is a distinct follow-on bug.
• This is genuinely actionable — the report points at the exact missing teardown (dispose the preview server's remote proxy session when the build completes / preview server closes).

Recommendation

Status: KEEP OPEN

Reasoning: This is a valid, well-documented, high-impact bug with a precise root-cause analysis pointing at missing session teardown in the Vite plugin (and the underlying referenced server handle in wrangler's startRemoteProxySession). It blocks remote bindings in all CI builds and needs a code fix.

Action: Route to the vite-plugin maintainers to verify the missing session.dispose() teardown path on preview-server close / build completion, and confirm whether the fix belongs in the plugin (disposing sessions from remoteProxySessionsDataMap) and/or in wrangler (unref-ing or closing the DevEnv listening server). A quick reproduction with remoteBindings: true + prerendering should confirm the hang.

Suggested Labels: none (avoiding guesses — apply package:vite-plugin / bug if those labels exist in the repo)

Suggested Comment

Thanks for the detailed writeup and root-cause analysis — this is really helpful. It does look like the remote proxy session created for the preview/prerender pass isn't being disposed once the build finishes, leaving the DevEnv's referenced server handle open and preventing the process from exiting. We'll take a look at adding proper teardown of the sessions in remoteProxySessionsDataMap (and/or ensuring the underlying startRemoteProxySession server is closed) when the build completes. If you have a minimal repo we can clone and run, that would help us verify the fix, but the analysis you've provided already gives us a clear starting point.

Structured summary (JSON)

{
  "issueNumber": 15173,
  "title": "[vite-plugin] vite build never exits when remoteBindings is enabled — remote proxy session is never disposed",
  "githubUrl": "https://github.com/cloudflare/workers-sdk/issues/15173",
  "recommendation": "KEEP OPEN",
  "difficulty": "medium",
  "reasoning": "Valid, well-documented high-impact bug: the remote proxy session's referenced server handle is never disposed after vite build's prerender pass, so the process hangs. Root cause is precisely traced to missing teardown in the Vite plugin and wrangler's startRemoteProxySession.",
  "suggestedAction": "Route to vite-plugin maintainers to add teardown/disposal of sessions in remoteProxySessionsDataMap (and/or close the DevEnv listening server in startRemoteProxySession) when the build completes; verify with a remoteBindings + prerendering repro.",
  "hasSuggestedComment": true,
  "suggestedLabels": []
}