[BUG]: use byte offset in full-text reader rather than token position

[codetheweb]

Description of changes

The full-text reader had a bug where it used the positions of tokens to determine whether the tokens appeared sequentially, rather than using the byte offset of tokens. This was problematic because the index stores byte offsets. Since Unicode characters can be many bytes wide, we cannot guarantee that the stored byte offsets are strictly consecutive.

Test plan

How are these changes tested?

Added a test that fails on main.

Documentation Changes

Are all docstrings for user-facing APIs updated if required? Do we need to make documentation changes in the docs section?

n/a

[github-actions]

Reviewer Checklist

Please leverage this checklist to ensure your code review is thorough before approving

Testing, Bugs, Errors, Logs, Documentation

• Can you think of any use case in which the code does not behave as intended? Have they been tested?
• Can you think of any inputs or external events that could break the code? Is user input validated and safe? Have they been tested?
• If appropriate, are there adequate property based tests?
• If appropriate, are there adequate unit tests?
• Should any logging, debugging, tracing information be added or removed?
• Are error messages user-friendly?
• Have all documentation changes needed been made?
• Have all non-obvious changes been commented?

System Compatibility

• Are there any potential impacts on other parts of the system or backward compatibility?
• Does this change intersect with any items on our roadmap, and if so, is there a plan for fitting them together?

Quality

• Is this code of a unexpectedly high quality (Readability, Modularity, Intuitiveness)

[propel-code-bot]

Fix for Full-Text Search with Unicode Characters

This PR fixes a bug in the full-text reader where token positions were used instead of byte offsets when determining if tokens appeared sequentially. Since Unicode characters can be variable-width (multiple bytes), using token positions led to incorrect search results when texts contained multi-byte characters. The fix uses byte offsets to properly handle Unicode text.

Key Changes:
• Changed position adjustment logic to use byte offsets instead of token positions
• Simplified the token position adjustment algorithm
• Added a test case for documents containing multi-byte characters

Affected Areas:
• Full-text search implementation in rust/index/src/fulltext/types.rs

This summary was automatically generated by @propel-code-bot