vitest browser mode hangs when coverage-v8 or istanbul is installed, even when coverage is disabled

[RobbyRabbitman]

Describe the bug

I would like to report some weird observation and maybe some1 can look on that: vitest browser mode hangs when coverage-v8 or istanbul is installed, even when coverage is disabled.

I generated my workspace with the vp cli and it created some pnpm overrides, but Im unsure how that effects additional packages of the vitest eco system. vite-plus@0.1.20 has "@vitest/coverage-v8": 4.1.5 as an optional peer, so i guess its fine installing it. I also tried to understand this reexporting here https://github.com/voidzero-dev/vite-plus/blob/main/packages/test/BUNDLING.md. Idk if the issue is related to that or if its a vitest issue - I did not find anything in their repo. Maybe this issue vitest-dev/vitest#10252 but its not using browser mode.

packages:
  - e2e/*
  - packages/*
  - tools/*
catalog:
  "@types/lodash-es": 4.17.12
  "@types/node": 25.6.0
  '@vitest/coverage-istanbul': 4.1.5
  "@vitest/coverage-v8": 4.1.5
  lodash-es: 4.18.1
  playwright: 1.59.1
  typedoc: 0.28.19
  typedoc-plugin-markdown: 4.11.0
  typescript: 5.9.3
  vite: npm:@voidzero-dev/vite-plus-core@0.1.20
  vite-plus: 0.1.20
  vitest: npm:@voidzero-dev/vite-plus-test@0.1.20
  why-is-node-running: 3.2.2
catalogMode: strict
cleanupUnusedCatalogs: true
engineStrict: true
overrides:
  typedoc: "catalog:"
  typescript: "catalog:"
  vite: "catalog:"
  vitest: "catalog:"
peerDependencyRules:
  allowAny:
    - vite
    - vitest
  allowedVersions:
    vite: "*"
    vitest: "*"
saveExact: true

Summary

In browser mode, Vitest fails before test collection with:

• [vitest] Browser connection was closed while running tests. Was the page closed unexpectedly?
• [birpc] rpc is closed, cannot call "createTesters"

The run ends with no tests executed.

Repro commands

# Browser mode, no coverage
vp test run src/index.spec.ts --coverage.enabled false --reporter=verbose

# Browser mode, headed
vp test run src/index.spec.ts --coverage.enabled false --browser.headless false --reporter=verbose

# Browser mode, no isolation
vp test run src/index.spec.ts --coverage.enabled false --isolate=false --reporter=verbose

Actual Behavior

All browser-mode commands above fail with:

Error: Failed to run the test .../e2e/web-lib/src/index.spec.ts
Caused by: Error: [vitest] Browser connection was closed while running tests. Was the page closed unexpectedly?
Caused by: Error: [birpc] rpc is closed, cannot call "createTesters"

Vitest summary shows:

• Tests no tests
• Errors 1 error

Expected Behavior

Browser mode should connect, collect tests, and execute them.

Additional Findings

1. Disabling coverage does not fix it

   • --coverage.enabled false still reproduces the same browser/RPC error.

2. *Coverage package installation

   • Installing or not installing @vitest/coverage-istanbul and @vitest/coverage-v8 does have an effect - the error even happens with coverage disabled, the packages must not be installed actually so that tests run.

3. Not a stale-port artifact

   • Killing stale listeners before rerun still reproduces the same error.

4. --isolate=false does not fix it

   • Same browser connection/RPC-close error still occurs.

5. Non-browser mode does not hit this failure path

   • Node/non-browser test runs in the workspace complete normally.
   • This appears specific to browser mode.

Diagnostics run

• DEBUG=pw:browser,pw:api and DEBUG=vite:*,pw:api,pw:browser were used.
• Logs show browser launch/context/page creation and Vitest test page navigation succeed.
• Failure occurs before test collection starts (0 tests collected).

Environment (sanitized)

• OS: macOS
• Node.js: 24.x
• Vitest runtime via bundled package from vite-plus toolchain
• Browser provider: Playwright (Chromium)

Reproduction

x

Steps to reproduce

No response

System Info

0.1.20

Used Package Manager

pnpm

Logs

Validations

• Read the Contributing Guidelines.
• Check that there isn't already an issue for the same bug.
• Confirm this is a Vite+ issue and not an upstream issue (Vite, Vitest, tsdown, Rolldown, or Oxc).
• The provided reproduction is a minimal reproducible example.

[github-actions]

Hello @RobbyRabbitman 👋

Please provide a minimal reproduction using a GitHub repository. This helps us understand and resolve your issue much faster.

A good reproduction should be:

• Minimal – include only the code necessary to demonstrate the issue
• Complete – contain everything needed to run and observe the problem
• Reproducible – consistently show the issue with clear steps

If no reproduction is provided, issues labeled needs reproduction will be closed after 3 days of inactivity.

For more context on why this is required, please read: https://antfu.me/posts/why-reproductions-are-required