Build: Use HTTP check instead of detect-port for service readiness to prevent EADDRINUSE

[Copilot]

Closes #33650

detect-port can give false negatives in CI container environments — reporting a port as free even when a server is already bound to it (typically due to IPv4/IPv6 interface differences). When this happens during yarn task e2e-tests-dev -s e2e-tests-dev, the dev task gets 'notserving' status, causing the task runner to attempt starting Storybook again, resulting in EADDRINUSE: address already in use 127.0.0.1:6006.

Changes

• scripts/tasks/dev.ts / scripts/tasks/serve.ts: Replace detect-port TCP check in ready() with an HTTP fetch to /iframe.html. This matches what the CI "wait for port" step does and is immune to the IPv4/IPv6 false-negative issue.

- return (await detectFreePort(port)) !== port;
+ try {
+   await fetch(`http://localhost:${port}/iframe.html`, { signal: AbortSignal.timeout(1000) });
+   return true;
+ } catch {
+   return false;
+ }

The HTTP check verifies Storybook is actually serving content rather than just testing port occupancy, making it a more accurate signal of service readiness.

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Summary by CodeRabbit

• Refactor
  • Updated server readiness detection to use active HTTP endpoint verification instead of port detection, providing more reliable confirmation of server availability during development.

[nx-cloud]

View your CI Pipeline Execution ↗ for commit 810c15c

Command	Status	Duration	Result
nx run-many -t compile,check,knip,test,pretty-d...	❌ Failed	11m 45s	View ↗

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☁️ Nx Cloud last updated this comment at 2026-02-25 11:43:20 UTC

[github-actions]

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📥 Commits

Reviewing files that changed from the base of the PR and between bbca9fc and 810c15c.

📒 Files selected for processing (2)

• scripts/tasks/dev.ts
• scripts/tasks/serve.ts

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📝 Walkthrough

Walkthrough

Both dev and serve task scripts replaced port availability detection with HTTP probing. The updated ready() function attempts to fetch http://localhost:<port>/iframe.html with a 1-second timeout, returning true on success and false otherwise. The public API remains unchanged.

Changes

Cohort / File(s)	Summary
Readiness Check Refactor scripts/tasks/dev.ts, scripts/tasks/serve.ts	Replaced port detection via detect-port library with HTTP fetch probe to /iframe.html endpoint; added try/catch error handling and 1s timeout to verify server responsiveness instead of port availability.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

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