Fix body block cache index offset when header exists by hackerwins · Pull Request #160 · wafflebase/wafflebase

hackerwins · 2026-04-25T23:17:07Z

Summary

When a header element is present, tree path index for body blocks is offset by 1. The cache update in splitBlock, mergeBlock, and deleteBlock used the raw tree path index as the array index into doc.blocks, causing off-by-one writes — the split overwrote the wrong block and duplicated content (e.g. "asdf\nasdf" instead of "asdf\n").
Extract localBlockIndex() helper that resolves the correct body-relative index via getRegionBlocks().topIndex, and apply it to all four cache-update sites.

Test plan

Added tests for splitBlock, mergeBlock, deleteBlock with header present
All 106 existing YorkieDocStore tests pass
Full verify:fast + verify:self pass (pre-push hook)
Manual verification on production document (wafflebase.io)

🤖 Generated with Claude Code

Summary by CodeRabbit

Release Notes

Bug Fixes
- Improved reliability of document block operations (split, merge, delete) with complex document structures.
Tests
- Added comprehensive test coverage for block cache correctness in various document scenarios.

When a header element is present, the tree path for body blocks is offset by 1 (header occupies tree index 0). The cache update in splitBlock, mergeBlock, and deleteBlock used the raw tree path index as the array index into doc.blocks, causing off-by-one writes — the split overwrote the wrong block and duplicated content (e.g. "asdf\nasdf" instead of "asdf\n"). Extract localBlockIndex() helper that resolves the correct body-relative index via getRegionBlocks().topIndex, and apply it to all four cache-update sites (insertBlockAfter already had the fix inline). Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>

coderabbitai · 2026-04-25T23:17:17Z

📝 Walkthrough

Walkthrough

Introduces a shared localBlockIndex helper to standardize in-memory block index resolution for both cell-internal and top-level block paths. Refactors block cache mutations (insertBlockAfter, deleteBlock, splitBlock, mergeBlock) to use this helper instead of duplicating conditional logic. Adds test coverage for cache index correctness when headers are present.

Changes

Cohort / File(s)	Summary
Block Index Helper Refactoring `packages/frontend/src/app/docs/yorkie-doc-store.ts`	Introduces `localBlockIndex` helper to centralize block index resolution logic. Updates four block cache mutation sites (`insertBlockAfter`, `deleteBlock`, `splitBlock`, `mergeBlock`) to use the helper, eliminating conditional duplication and correctly handling region-relative indexing for merged blocks.
Cache Index Tests `packages/frontend/tests/app/docs/yorkie-doc-store.test.ts`	Adds new test suite verifying cache index correctness when a header is present. Tests confirm `splitBlock` uses body-relative indices, `mergeBlock` combines intended adjacent body blocks, and `deleteBlock` removes correct body blocks without duplication.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

Add intent-preserving cell structural edits (Phase 8) #156: Modifies the same cache-indexing and block-mutation logic in yorkie-doc-store.ts (insertBlockAfter, deleteBlock, splitBlock, mergeBlock) with index handling for cell-internal edits.
Prevent image duplication when splitting blocks near images #159: Touches the same file and splitBlock function, refactoring index resolution to address duplication concerns.
Use native Yorkie Tree split/merge for concurrent convergence #126: Modifies splitBlock and mergeBlock along with in-memory block-cache index resolution in the same file.

Poem

🐰 A helper hops to save the day,
Block indices find their way,
Mutations merged with grace so bright,
The cache now shines with unified light! ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically identifies the main fix: resolving a cache index offset bug that occurs when a header element is present in the document structure.
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.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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✨ Finishing Touches

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Commit on current branch

🧪 Generate unit tests (beta)

Create PR with unit tests
Commit unit tests in branch fix/split-cache-index-offset

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github-actions · 2026-04-25T23:20:30Z

Verification: verify:self

Result: ✅ PASS in 123.0s

Lane	Status	Duration
sheets:build	✅ pass	14.0s
docs:build	✅ pass	8.1s
verify:fast	✅ pass	62.0s
frontend:build	✅ pass	16.4s
verify:frontend:chunks	✅ pass	0.3s
backend:build	✅ pass	4.9s
cli:build	✅ pass	1.9s
verify:entropy	✅ pass	15.3s

Verification: verify:integration

Result: ✅ PASS

codecov · 2026-04-25T23:20:56Z

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

hackerwins merged commit fb7a831 into main Apr 25, 2026
1 check passed

hackerwins deleted the fix/split-cache-index-offset branch April 25, 2026 23:18

coderabbitai Bot mentioned this pull request Apr 26, 2026

Work around editByPath merge failure after split #163

Merged

4 tasks

hackerwins mentioned this pull request May 1, 2026

Bump version to v0.3.6 #174

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3 tasks

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Fix body block cache index offset when header exists#160

Fix body block cache index offset when header exists#160
hackerwins merged 1 commit into
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fix/split-cache-index-offset

hackerwins commented Apr 25, 2026 •

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coderabbitai Bot commented Apr 25, 2026 •

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hackerwins commented Apr 25, 2026 •

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