Dependency optimizer recreates cache directories after server.close() resolves — Vite 8.1.2 and 8.3.4

Reproduction

https://gist.github.com/raskum1984/dc5bacb0a0f9ff804236e7e0cbc12966

Download/clone all nine files, then follow README.md:

node setup.mjs
npm ci --prefix baseline
npm ci --prefix candidate
node run.mjs baseline
node run.mjs candidate

Expected behavior

After await server.close() resolves, and a test-owned cache directory has been
removed, Vite should not recreate optimizer output inside that directory.

Actual behavior

Two concurrent middleware-mode Vite servers use independent caches. Both Vite
8.1.2 and 8.3.4 successfully load a simple React SSR module and resolve their
original close() calls. Each owned cache is then removed successfully; the
child logs an empty cache-root snapshot. The child exits naturally with code 0.

Inspection by the parent after child exit finds recreated server-*/deps_temp_*
directories containing react.js, react-dom_server.js, sourcemaps and Rolldown
runtime output. The parent exits 1 to report this lifecycle failure; it does not
force child termination or suppress an error.

This occurred in three earlier isolated runs per version, affecting six caches
per version, and in two further public-reproduction checks per version,
including a check after installation using npm ci.

Environment

• macOS ARM64
• Node.js 24.21.0
• npm 11.19.0
• Baseline: Vite 8.1.2, Rolldown 1.1.3, Darwin ARM64 binding 1.1.3
• Candidate: Vite 8.3.4, normal transitive Rolldown 1.2.13, binding 1.2.13
• React and react-dom 19.2.7

Additional context

An original larger test suite intermittently experienced ENOTEMPTY during
test-owned cache removal after Vite's original close() resolved. Separate
native worker crashes were observed, but their connection to this lifecycle is
unconfirmed. This minimal reproduction demonstrates late cache output; it does
not itself reproduce the original ENOTEMPTY or native crash.

There are no sleeps, cleanup retries, shared cache, optimizer disabling or
concurrency reduction. Each attempt has a fresh cache root and child process.
The reproduction contains only synthetic code and locked dependencies, with no
application configuration, credentials or external service access.