Fixed a critical infinite loop bug in document_chunker.py that occurred
when the overlap parameter caused the chunker to not make forward progress.
Changes:
- Added ChunkWithPosition dataclass to track character positions
- Refactored chunk_text() to use regex word matching for accurate position tracking
- Added safety check to ensure forward progress (next_start_idx > start_idx)
- Changed return type from list[str] to list[ChunkWithPosition]
The bug manifested when:
1. end_idx reached len(word_matches) (processing last chunk)
2. next_start_idx = end_idx - overlap would not advance past start_idx
3. Loop would continue indefinitely without making progress
Fix ensures chunker always terminates by breaking when not advancing.
All 9 unit tests now pass in 1.66s (previously timing out at 180s).
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
Chris Coutinho