chore: improve yatp maintenance path

[vip892766gma]

Summary:

• Add unit tests covering edge cases for the priority queue: empty-pop behavior, equal-priority FIFO ordering stability, and saturating priority values at u64::MAX boundary, plus a small assertion fix/explicit error branch on invalid pool builder configuration (e.g. zero worker count) returning a clearer error rather than panicking later.
• Keep the change narrow so it is straightforward to review.

Notes:

• I kept this scoped to the relevant implementation and tests.

Summary by CodeRabbit

• Bug Fixes

  • Improved error messages when configuring the thread pool with invalid thread count values, now displaying both the configured minimum and maximum thread counts.

• Tests

  • Added validation tests for thread pool configuration edge cases.
  • Added comprehensive tests for priority queue behavior including empty queue handling, FIFO ordering with equal priorities, and boundary conditions.

[ti-chi-bot]

Welcome @vip892766gma! It looks like this is your first PR to tikv/yatp 🎉

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• 63f620f chore: improve yatp maintenance path

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: cc586c15-f0f5-474b-a134-dc920f6a4cab

📥 Commits

Reviewing files that changed from the base of the PR and between f3acdd2 and 63f620f.

📒 Files selected for processing (3)

• src/pool/builder.rs
• src/pool/tests.rs
• src/queue/priority.rs

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📝 Walkthrough

Walkthrough

This PR enhances validation error messaging in the thread pool builder and adds comprehensive test coverage for the priority queue. The pool builder now reports conflicting thread count values in panic messages, with a corresponding test. Additionally, three new priority queue tests cover empty queue behavior, FIFO ordering under equal priorities, and boundary conditions at maximum priority values.

Changes

Validation and Test Coverage Improvements

Layer / File(s)	Summary
Pool builder validation with error message src/pool/builder.rs, src/pool/tests.rs	Builder::freeze_with_queue validation assertion now includes a formatted error message that reports both min_thread_count and max_thread_count values. A new #[should_panic] test confirms the panic behavior when min exceeds max.
Priority queue edge case and ordering tests src/queue/priority.rs	Three new tests validate empty queue handling, FIFO tie-breaking for equal-priority tasks via internal sequence counter, and priority ordering at u64::MAX boundaries.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 A rabbit hops through tests with glee,
Checking queues and thread counts free,
Edge cases caught, no panics hidden,
Validation clear—errors well-written!

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 inconclusive)

Check name	Status	Explanation	Resolution
Title check	❓ Inconclusive	The title 'improve yatp maintenance path' is vague and does not clearly convey the specific changes made, which include adding unit tests and improving error validation.	Consider a more descriptive title such as 'test: add priority queue and builder validation tests' to better reflect the actual changeset.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
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

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