fix(banner): preserve color when picker is cancelled

[barbatdev]

Closes #301

Summary

• Treat banner color picker cancellation as a no-op in both command flows.
• Preserve the previously saved color without rewriting banner.json or showing a misleading notification.
• Add runtime coverage for direct, invalid-argument, and nested picker cancellation.

Changes

File	Change
extensions/startup-banner.ts	Return before persistence and notification when a color picker is cancelled.
tests/runtime-harness.mjs	Verify saved colors survive cancellation across both entry points.

Test plan

• pnpm run test:harness
• git diff --check
• Independent verification passed.
• Native four-lens review completed without severe findings.
• Pre-commit, pre-push, and pre-PR gates validated the reviewed candidate.

PR type

• Bug fix
• New feature
• Documentation only
• Code refactoring
• Maintenance/tooling
• Breaking change

Contributor checklist

• Linked an approved issue.
• Uses one type:* label.
• Tests are included with the behavior change.
• No documentation update is required for unchanged command syntax.
• Commit follows Conventional Commits.
• No AI attribution or co-author trailer.

Out of scope

Banner defaults, rendering, persistence schema, and command syntax remain unchanged.

Summary by CodeRabbit

• Bug Fixes

  • Cancelling the banner color selector no longer changes the saved configuration.
  • Invalid or missing color values now open the selector safely.
  • Directly selected valid colors continue to apply as expected.

• Tests

  • Added coverage for cancellation scenarios, unchanged settings, notifications, and selector behavior.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 0c64766d-aa5b-45e6-a0d2-e0b6bd1d595d

📥 Commits

Reviewing files that changed from the base of the PR and between 19b0ed7 and 995e7bf.

📒 Files selected for processing (2)

• extensions/startup-banner.ts
• tests/runtime-harness.mjs

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📝 Walkthrough

Walkthrough

The banner menu and color command now treat cancelled color selection as a no-op. Runtime harness tests cover direct, invalid-argument, and nested picker cancellation.

Changes

Banner color cancellation

Layer / File(s)	Summary
Handle cancelled color selection extensions/startup-banner.ts	The banner menu and color command now apply a color only when selection succeeds. Valid command arguments are applied directly. Invalid or absent arguments open the picker.
Validate cancellation behavior tests/runtime-harness.mjs	Tests verify unchanged configuration, no notifications, expected picker counts, and semantic configuration round-trips across cancellation flows.

Estimated code review effort: 2 (Simple) | ~10 minutes

Mergeability Score: ⚪ Minimal · up to 995e7

The change makes picker cancellation a no-op so saved banner colors are preserved without unnecessary persistence or notifications; no actionable merge-blocking risk remains after normal checks.

Suggested reviewers: alan-thegentleman

🚥 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 summarizes the fix for preserving the banner color when the picker is cancelled.
Linked Issues check	✅ Passed	The changes address issue #301 in both banner color flows and add regression coverage for preserved configuration and suppressed notifications.
Out of Scope Changes check	✅ Passed	All changes are limited to the banner cancellation fix and its runtime regression tests.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[Alan-TheGentleman]

Merged. Verified the bug-catching power of the new harness block rather than trusting it: reverted extensions/startup-banner.ts to main and the block failed with banner-color cancel must not rewrite banner.json — so it genuinely pins the regression, and the picker-open counts (1, 1, 2) mean a 'fix' that just stopped opening the picker wouldn't pass either.

Nice catch on the root cause: await ctx.ui.select(...) as BannerColor swallowing the cancel into undefined, then JSON.stringify dropping the key and the next read normalizing to the default — a silent destroy of a non-default choice. The falsy guard is safe here because every BANNER_COLORS entry is a non-empty string.

Post-merge with current main: harness exit 0, 1113 pass / 0 fail / 1 pre-existing skip. Thanks 👏