/@vite/client stub's createHotContext returns a hot context without the documented "data" property #11528

Describe the bug

I am doing: running unit tests with environment: 'happy-dom'. Vite's importAnalysis
plugin rewrites any module whose source references import.meta.hot by prepending

import { createHotContext as __vite__createHotContext } from "/@vite/client";
import.meta.hot = __vite__createHotContext("…")`,

and Vitest serves the /@vite/client id with a hard-coded stub (defaultClientStub in
packages/vitest/src/runtime/moduleRunner/moduleEvaluator.ts).

What I expect is: the stub's hot context to honor the documented ViteHotContext contract
(https://vite.dev/guide/api-hmr readonly data, "Vite creates one import.meta.hot.data
object for each module path"). The stub already replicates the rest of the surface
(accept, prune, dispose, decline, invalidate, on, send).

What actually happens is: import.meta.hot is the stub object (truthy, so if (import.meta.hot)
guards pass) but import.meta.hot.data is undefined, so any legitimate hot.data[key] reader
crashes. Real-world example: @lexical/extension's HMRExtension (wired with the documented
configExtension(HMRExtension, { hot: import.meta.hot ?? null }) pattern) throws
TypeError: Cannot read properties of undefined (reading 'lexicalHMR:…') in every unit test
that mounts an editor.

Reproduction

https://github.com/Alxs39/vitest-hot-data-repro : npm install, then npm test.

Output (vitest 5.0.3, latest):

FAIL  hmr-data.test.js > import.meta.hot exposes the documented data object
AssertionError: expected undefined to deeply equal {}

- Expected:
{}

+ Received:
undefined

The first assertion (expect(import.meta.hot).toBeDefined()) passes the stub exists, only the documented data property is missing.

System Info

System:
    OS: macOS 26.5.2
    CPU: (10) arm64 Apple M4
    Memory: 1.09 GB / 32.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 26.8.1 - /Users/alexis/.local/bin/node
    npm: 11.19.0 - /Users/alexis/.local/bin/npm
    pnpm: 11.10.0 - /Users/alexis/.local/bin/pnpm
  Browsers:
    Safari: 26.5.2
  npmPackages:
    vitest: 5.0.3 => 5.0.3

Used Package Manager

npm

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.