[hyuraku]

BottleTransition keeps existing bottles while a new macOS release is bootstrapped. Its comment had a TODO to remove the class once HOMEBREW_MACOS_NEWEST_SUPPORTED is 27.

In #24237 I removed it, but the review asked to keep it. It prevented us from losing bottles during this year's transition, and we need the same protection for future macOS releases.

This change replaces the TODO with instructions for updating MACOS each year. It also notes that test/bottle_transition_spec.rb uses release symbols directly, so they need the same update.

No behaviour change. Only the comment changes.

---

• Have you followed our Contributing guidelines?
• Have you checked for other open Pull Requests for the same change?
• Have you explained what your changes do? Performance claims (e.g. "this is faster") must include brew benchmark results.
• Have you explained why you'd like these changes included, not just what they do?
• For bug fixes, have you given step-by-step brew commands to reproduce the bug?
• Have you written new tests (excluding integration tests)? Here's an example.
• Have you successfully run brew lgtm (style, typechecking and tests) locally?

---

• I did not use AI/LLM to create this PR, or I disclosed the tool/model below and reviewed its output; I did not attribute commits to AI and will answer maintainer questions and review comments myself without AI/LLM.

AI (Claude Code) summarised the review and drafted the new comment. I reviewed the wording and ran brew lgtm locally.

---

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

• Configuration used: Organization UI
• Review profile: CHILL
• Plan: Advanced
• Run ID: 561dd6f6-7f16-4bc9-8ae6-a842bcf81753

📥 Commits

Reviewing files that changed from the base of the PR and between 1220a4a and 5287873.

📒 Files selected for processing (1)

• Library/Homebrew/bottle_transition.rb

Included review availability: This review used your included allowance. Your plan provides up to 10 included reviews per hour; 9 remain after this review.

📜 Recent review details

⏰ Context from checks skipped due to timeout. (19)

• GitHub Check: docker (x86_64 Ubuntu 26.04)
• GitHub Check: docker (arm64 Ubuntu 24.04)
• GitHub Check: docker (arm64 Ubuntu 26.04)
• GitHub Check: docker (x86_64 Ubuntu 24.04)
• GitHub Check: tests (load-only Linux)
• GitHub Check: Analyze
• GitHub Check: docs
• GitHub Check: tests (generic OS, 2/2)
• GitHub Check: tests (online, 2/2)
• GitHub Check: tests (load-only macOS)
• GitHub Check: tests (online, 1/2)
• GitHub Check: tests (generic OS, 1/2)
• GitHub Check: tests (macOS, 2/2)
• GitHub Check: tests (no Sorbet)
• GitHub Check: tests (Linux, 1/2)
• GitHub Check: tests (Linux, 2/2)
• GitHub Check: tests (macOS, 1/2)
• GitHub Check: syntax
• GitHub Check: workflow_syntax

🔇 Additional comments (1)

Library/Homebrew/bottle_transition.rb (1)

8-12: LGTM!

📝 Summary

Summary by CodeRabbit

• Documentation
  • Clarified maintenance guidance for macOS release checks, including the version threshold at which checks become active and the release information that needs updating. No end-user-facing behavior changes are noted.

The class comments now describe release updates for MACOS and test release symbols. They also state that checks remain inactive until MACOS is newer than the supported version. The previous removal TODO was removed.

Changes: macOS bottle transition guidance

Layer / File(s)	Summary
Release-update guidance Library/Homebrew/bottle_transition.rb	The comments now describe updating MACOS and test release symbols for each new macOS release. They state that checks remain inactive until MACOS is newer than the supported version. The removal TODO was removed.

Priority: ⬇️ Low

Estimated code review effort: 1 (Trivial) | ~3 minutes

Change: Other

Suggested reviewers: p-linnane

Merge Risk: ⚪ Minimal · up to 52878

This change updates maintainer guidance without changing runtime behavior. The guidance matches the activation rule, and no concrete merge-blocking risk remains.

### Architecture Summary

Architecture risk: 🔵 Low · up to 52878

The change affects 1 system.

Changed systems: Library

Architecture concerns
No architecture-level concerns identified.

Review details

Systems and components

• observed — Library (service) was modified; 1 changed file maps to changed impact.

Before / after behavior

• observed — Modified behavior in Library/Homebrew/bottle_transition.rb: The comments replace the instruction to remove the class and its callers when HOMEBREW_MACOS_NEWEST_SUPPORTED reaches 27 with guidance to update MACOS and test release symbols for each new macOS release, and state that checks remain inactive until MACOS is newer than the supported version.

Pre-merge checks · 4

Passed checks (4 passed)

Check name	Status	Explanation
Title check		The title clearly and concisely describes the main change: documenting the yearly BottleTransition update.
Description check		The description accurately explains the comment-only change, its purpose, and the required yearly updates.
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

• Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

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

[p-linnane]

Thanks!