fix(ci): classify SDK-less Xcode pin failures

[teamleaderleo]

Problem

The merged Xcode pin handling classifies missing pin paths as machine failures, but the focused-test redispatch helper still missed two equivalent selector errors: an installed Xcode with no usable SDK and the legacy pool-pin message. SDK-less selector errors also omitted the installed-Xcode inventory needed to diagnose the host.

Change

• classify SDK-less and legacy pool-pin selector failures as machine failures in machine_failure.py;
• include the installed Xcode inventory in both SDK-less selector annotations;
• add focused regression coverage for both paths.

The first PR (#15598) already added the runtime marker and classifier used by the main CI attribution path. This follow-up keeps the focused redispatch and selector diagnostics consistent with it.

---

^{Need help on this PR? Tag @codesmith-bot with what you need. Autofix is disabled.}

---

Summary by cubic

Classifies SDK-less and legacy pool-pin Xcode selection failures as machine failures, and reports the installed Xcode inventory in the SDK-less error messages for easier host diagnosis.

• Adds the two missing error patterns to the machine_failure.py classifier.
• Includes the installed Xcode list in both SDK-less error messages.
• Adds regression coverage for both failure paths in the fast-path and classifier tests.

^{Written for commit 7ff76c0. Summary will update on new commits.}

[coderabbitai]

Navigate logical layers of code changes, visualize relationships, and explore their blast radius.

Note

Currently processing new changes in this PR. This may take a few minutes, please wait...

⚙️ Run configuration

Configuration used: Repository: manaflow-ai/cmux/.coderabbit.yaml

Review profile: ASSERTIVE

Plan: Advanced

Run ID: 30637720-df3e-446f-86df-b41d2f09cdb0

📥 Commits

Reviewing files that changed from the base of the PR and between 551a923 and 7ff76c0.

📒 Files selected for processing (4)

• scripts/ci/machine_failure.py
• scripts/select-ci-xcode.sh
• tests/test_ci_machine_failure.py
• tests/test_ci_xcode_selection_fast_path.sh

 _________________________________________
< Make it work, make it right, make it 🥕. >
 -----------------------------------------
  \
   \   (\__/)
       (•ㅅ•)
       / 　 づ

✨ Finishing Touches

📝 Generate docstrings

• Commit to this branch
• Create a new PR

🧪 Generate unit tests (beta)

• Commit to this branch
• Create a new PR

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[github-actions]

Dogfood tours of 7ff76c04

sidebar-and-chrome-tour at 7ff76c04: passed (run)

Key frames of sidebar-and-chrome-tour at 7ff76c0

_{Tours are picked by the paths globs in dogfood/scenarios/*.json; a Dogfood-tours: a, b line in the description picks them instead (none turns this off). Look at every frame before merging: a green tour only means no step failed.}

[github-actions]

Merge receipt for 7ff76c048f: every check was green at merge (25 verified; 25 skipped by policy). Full suite runs on main after merge.