Developing on Windows

Issues that only reproduce on Windows. They are kept here rather than in the shared config, because they do not apply on the Linux runners this template’s CI uses.

@cloudflare/vitest-pool-workers + an R2 bucket binding: “Isolated storage failed”

Symptom: with an R2 bucket binding and @cloudflare/vitest-pool-workers default settings, a test run ends with:

Error: Isolated storage failed. There should be additional logs above.
  at WorkersTestRunner.updateStackedStorage

The tests themselves pass; the suite fails. The “additional logs above” are, on Windows:

EBUSY: resource busy or locked, unlink
  ...\miniflare-<hash>\r2\miniflare-R2BucketObject\<hash>.sqlite

Cause: isolated storage snapshots by unlinking miniflare’s backing SQLite file between suites. Windows won’t unlink a file whose handle is still open, so the rollback fails. It reproduces with beforeAll and beforeEach seeding alike, which makes the seeding pattern a red herring when diagnosing it.

Workaround, in the affected vitest.config.ts:

export default defineWorkersConfig({
  test: { poolOptions: { workers: { isolatedStorage: false } } },
});

Safe when tests seed distinct keys and don’t mutate shared state. Do not set this template-wide — it’s a real safety property for suites that do mutate shared state, and this template ships no R2 binding by default.

Verified: the failure, the EBUSY cause, and that isolatedStorage: false resolves it — on Windows 11, @cloudflare/vitest-pool-workers 0.9.14, wrangler 4.105.0.

Inferred, not verified: that this is Windows-specific — not reproduced on Linux/macOS. This template’s CI workflow targets ubuntu, so CI would likely never see it either way, which is exactly why this is documented here rather than baked into the shared vitest config.