[Bug] "Parcel.watch()" instruction ends even if the server is not yet ready

[anemer]

🐛 bug report

Parcel watcher (Parcel.watch()) seems to end before server is actualy ready.

🎛 Configuration

  const port = 1234;
  const bundler = new Parcel({
    entries: "./index.html",
    defaultConfig: "@parcel/config-default",
    serveOptions: { port },
  });
  await bundler.watch();

reproduction steps: microsoft/playwright#35879 (comment)

Package.json : https://github.com/testndev/bugs-report-reproduction/blob/main/package.json

🤔 Expected Behavior

Parcel should return the hand at least with server up.

😯 Current Behavior

Parcel returns the hand even if server is not ready yet.

Requesting the server just after the end of bundler.watch() returns a net::ERR_CONNECTION_REFUSED error with Playwright for example.

page.goto: net::ERR_CONNECTION_REFUSED at http://localhost:1234/

note: frequent but not systematic behavior.

🔦 Context

The bug was first open at Playwright: microsoft/playwright#35879

I have some scripts (with Playwright) that request a web app served by Parcel.

For example to take a PDF snapshot of "functional test coverage page".

💻 Code Sample

See : https://github.com/testndev/bugs-report-reproduction

🌍 Your Environment

Software	Version(s)
Parcel	2.14.4 & 2.15.0
Node	23.11.0
npm/Yarn	npm: 10.9.2
Operating System	Ubuntu 24.04.2

See also: microsoft/playwright#35879