test(react-grab): cover freeze-updates replay order and recovery arms

[aidenybai]

Summary

freeze-updates.ts — the internal-dispatcher freeze/replay path, flagged as the top fragile-internals gap (65% lines, depth-weighted 42%, an unreached depth-7 block) — had zero unit coverage. This mocks bippy's fiber/renderer surface and the recoverable-error logger to drive the real exported freezeUpdates end-to-end:

• Hook-queue buffering: pending reads are masked to null while frozen; on resume every buffered update replays in chain order. Three writes during the freeze exercise all four mergePendingChains arms ((null, single), (single, single), (multi, multi)) and the resulting circular chain is asserted to extract as ["a","b","c","d"] — proving the merge produces a complete, walkable loop. Also covers the pre-existing pending chain captured at freeze time.
• Context-dependency freezing: value masked to the frozen snapshot while paused; buffered write applied on resume.
• Dispatcher replay order: store callbacks → transitions → state updates.
• Recovery arms (try/catch): a throwing buffered update is swallowed + logged ("Callback failed during state replay") and replay continues; a scheduleUpdate throw in the post-resume microtask flush is swallowed + logged ("scheduleUpdate failed during unfreeze").
• Lifecycle guards: re-freeze while frozen and double-resume are no-ops.

The bippy mock is scoped to this file (vitest isolates module mocks per file), so other suites are unaffected.

Test plan

• vp test run tests — 65 unit tests pass (7 in this file)
• pnpm typecheck clean
• pnpm lint clean

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Note

Low Risk
Test-only change with no production code modifications; mocks are isolated to the new test file.

Overview
Adds freeze-updates.test.ts, the first unit coverage for freezeUpdates, using file-scoped mocks of bippy (fiber roots, renderers, composite fibers) and logRecoverableError so React internals can be exercised in Node without a real renderer.

The suite drives the real export through lifecycle (nested freeze and double-resume are safe), hook-queue buffering (masked pending while frozen; replay in chain order, including pre-freeze pending and merged writes), context dependency masking until resume, dispatcher replay order (store → transition → state), and recovery (throwing replay continues with logging; scheduleUpdate failures in the post-resume microtask are logged).

^{Reviewed by Cursor Bugbot for commit dce3de1. Bugbot is set up for automated code reviews on this repo. Configure here.}

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Summary by cubic

Add end-to-end tests for freezeUpdates to cover freeze/replay behavior, dispatcher replay order, and error recovery. The suite mocks bippy and the recoverable-error logger to verify hook-queue buffering (merge paths and pre-existing chains), context value masking, lifecycle guards, and logging when callbacks or scheduleUpdate throw.

^{Written for commit dce3de1. Summary will update on new commits.}

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Project	Deployment	Actions	Updated (UTC)
react-grab-storybook	Ready	Preview, Comment	Jun 29, 2026 3:33am
react-grab-website	Ready	Preview, Comment	Jun 29, 2026 3:33am

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commit: dce3de1

[cubic-dev-ai]

No issues found across 1 file

_{Re-trigger cubic}

[aidenybai]

Superseded by #510, which consolidates all the test-coverage PRs into one. Commits preserved there.