fix: use rolling cache key for clcache on Windows to get cache hits

[spoorcc]

The static key caused clcache to restore a stale entry after every MSVC
runner update, resulting in 0 hits / 701 misses on every build run. A
sha-based key with a prefix restore-keys fallback and save-always mirrors
the rolling strategy used by ccache-action on Linux/macOS.

https://claude.ai/code/session_01XTvMZtPH8WpuiRBZkqWiHk

Summary by CodeRabbit

• Chores
  • Improved Windows build caching configuration to enhance cache retrieval efficiency and consistency across commits.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro

Run ID: a70f59ef-bcec-40f1-a329-662e2e21f3ff

📥 Commits

Reviewing files that changed from the base of the PR and between b1caec8 and 9192d1e.

📒 Files selected for processing (1)

• .github/workflows/build.yml

Walkthrough

Updated the Windows .clcache cache configuration in the GitHub Actions build workflow to use commit SHA-based cache versioning, added a restore fallback for earlier commits on the same platform, and enabled the save-always flag to ensure cache persistence regardless of job state.

Changes

Cohort / File(s)	Summary
CI/CD Configuration .github/workflows/build.yml	Updated Windows .clcache action/cache with commit SHA-based key, added restore-keys fallback for platform/job caches, and enabled save-always to persist cache across job states.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

Possibly related PRs

• Spoorcc/issue820 (Fix caching during build) #860: Introduces the initial Windows .clcache caching step that this PR refines with improved versioning and fallback behavior.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main change: implementing a rolling cache key strategy for clcache on Windows to improve cache hit rates.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch claude/fix-nuitka-clcache-windows-IlOuU

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In @.github/workflows/build.yml:
- Line 82: Replace the unsupported save-always input on actions/cache@v5 by
splitting restore and save into separate steps: use actions/cache@v5 with the
restore step (actions/cache/restore) before build, then add a distinct cache
save step (actions/cache/save) after build guarded with if: always() so it runs
even on failure; also read and use the cache-hit output (cache-hit) from the
restore step to avoid unnecessary overwrites when implementing the save step.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro

Run ID: beea262a-c35c-4750-90ab-33083730990c

📥 Commits

Reviewing files that changed from the base of the PR and between 9d54759 and b1caec8.

📒 Files selected for processing (1)

• .github/workflows/build.yml