On "WASM Emscripten 3.x" buildbot, the "PyRepl in Chrome smoke test" step failed with:https://buildbot.python.org/#/builders/1810/builds/2113

Error: http://localhost:8787 is already used, make sure that nothing is running on the port/url or set reuseExistingServer:true in config.webServer.

The buildbot configuration allows 4 builds in parallel:

        cpw(            name="rkm-emscripten",            tags=['emscripten'],            not_branches=['3.10', '3.11', '3.12', '3.13'],            parallel_builders=4,        ),

So it's possible that 2 builds were running "PyRepl in Chrome smoke test" in parallel.

The port number 8787 is hardcoded inPlatforms/emscripten/browser_test/playwright.config.ts:

$ grep 8787 Platforms/emscripten/browser_test/playwright.config.ts    baseURL: 'http://localhost:8787',    command: 'npx http-server ../../../cross-build/wasm32-emscripten/build/python/web_example_pyrepl_jspi/ -p 8787',    url: 'http://localhost:8787',

cc@hoodmane@freakboy3742

Linked PRs

• gh-146352: In Emscripten pyrepl test, pick port dynamically #146375