[lucasbraum]

What and why

Closes #58.

forwards real workspace worker events without serializing the callback (packages/core/src/check/progress.test.ts) imported the shared packages/core/dist/index.js. pnpm build runs tsup with clean: true, which deletes and rewrites dist/. A build running at the same time as the test (the PR #54 case: lint and build in parallel) can remove the bundle while the child process imports it.

This was not a timing problem. There are no sleeps or fixed timeouts, and event order is fine: progress messages and the result share one worker port, so they arrive in order. Both failures I reproduced are the same ERR_MODULE_NOT_FOUND:

Error [ERR_MODULE_NOT_FOUND]: Cannot find module '/home/user/uptide/packages/core/dist/index.js' imported from /home/user/uptide/packages/core/[eval1]

The test exists to run the built worker (dist/worker.js), which the source-based suite never runs, so it still needs a real build. It now builds its own copy:

• tsup with the package's own config, --no-dts --no-sourcemap (about 1 s), into a fresh mkdtemp directory under packages/core/node_modules/. Being inside the package lets the bundle's bare imports (ts-morph, …) resolve.
• The directory is removed in afterAll.

No published code changes, so there is no changeset.

How it was verified

Each loop is 50 runs of vitest run src/check/progress.test.ts -t 'forwards real workspace' on a 4-core machine:

Load	Before	After
Busy loop on every core	0 / 50 failed	not rerun (time was never the cause)
pnpm build and pnpm lint looping in parallel	2 / 50 failed (4%), both ERR_MODULE_NOT_FOUND	0 / 50 failed

At a 4% rate, 0 failures in 50 runs could still happen by chance (about 13%), so I also checked the mechanism directly. With packages/core/dist deleted, the original test fails with the same error and the new one passes.

Checklist

• Tests for the change (with dist/ removed: the old test fails, the new one passes)
• pnpm lint && pnpm typecheck && pnpm test pass (core 927 passed / 15 skipped, cli 350 passed)
• README and docs updated if behavior changed (no behavior change)
• Changeset added if a user would notice (test-only, none)
• No new dependency (tsup is already a devDependency of @uptide/core)
• No private code, names or paths in fixtures, tests or docs
• The rules in CONTRIBUTING.md ("Rules that do not bend") still hold

Not changed here: other tests that read a package's dist/ (for example packages/cli/src/list-registry.test.ts and telemetry/sender.test.ts) could hit the same race when a build runs alongside them.

🤖 Generated with Claude Code

https://claude.ai/code/session_01EmiChUUtLdjbg6mNzKqVep

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