fix(chunker): stop overlap-stride crawl that shatters long-prose files#41
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fix(chunker): stop overlap-stride crawl that shatters long-prose files#41jdubdevs wants to merge 1 commit into
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smart_chunk applied the overlap window even when the emitted chunk was smaller than the overlap. cut_offset - overlap_chars then landed before the chunk's own start, and the .max(start_offset + 1) guard advanced the start by a single character — re-selecting the same nearby high-score break point and crawling forward one char at a time. Long, heading-dense prose files were shattered into hundreds of near-duplicate empty-heading micro-chunks (a 4.5k-word note produced 923 chunks; 907 of them 1-char-offset shrapnel), which (a) made the file unretrievable — its signal split below threshold so it never entered the candidate set — and (b) bloated the index ~10x (451 files held 91% of all chunks). Fix: only step back by the overlap window when the chunk is larger than it; otherwise advance fully to the cut. Guarantees forward progress, no crawl. Validated: the note re-chunks 923 -> 28; all chunks vectorize; a unique-phrase search returns it at rank 1. Adds test_smart_chunk_no_overlap_crawl regression. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Problem
smart_chunkapplies the overlap window even when the chunk it just emitted is smaller than the overlap.cut_offset - overlap_charsthen lands before the chunk's own start, and the.max(start_offset + 1)guard advances the start by a single character — which re-selects the same nearby high-score break point and crawls forward one char at a time.On long, heading-dense prose this shatters a file into hundreds of near-duplicate empty-heading micro-chunks. Observed on a real 4.5k-word note: 923 chunks, 907 of them 1-character-offset shrapnel (e.g.
"…ystem currently authorizing…","…stem currently authorizing…","…tem currently authorizing…").Impact:
Fix
Only step back by the overlap window when the emitted chunk is larger than that window; otherwise advance fully to the cut. Guarantees forward progress, eliminates the crawl. ~6 lines in
smart_chunk.Validation
test_smart_chunk_no_overlap_crawl(bounded chunk count + no degenerate micro-chunks). All 20 chunker tests pass.🤖 Generated with Claude Code