[2.8] MOD-12223: Fix underflow in BM25STD#7259
Merged
Conversation
Contributor
There was a problem hiding this comment.
Pull Request Overview
This PR fixes an underflow issue in the BM25STD scoring algorithm that could cause scores to jump unexpectedly during specific update/delete flows (MOD-12223).
- Added a guard in
CalculateIDF_BM25to prevent underflow whentotalDocs < termDocs - Added a comprehensive test case to verify the underflow fix and document the scoring behavior
Reviewed Changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
src/inverted_index.h |
Added MAX guard to prevent underflow in BM25STD IDF calculation when totalDocs < termDocs |
tests/pytests/test_scorers.py |
Added test case verifying that BM25STD scores don't jump unexpectedly during update/delete operations |
💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## 2.8 #7259 +/- ##
=======================================
Coverage 87.44% 87.44%
=======================================
Files 203 203
Lines 34783 34784 +1
=======================================
+ Hits 30416 30418 +2
+ Misses 4367 4366 -1
Flags with carried forward coverage won't be shown. Click here to find out more. ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
|
alonre24
approved these changes
Nov 9, 2025
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Backport #7223 to
2.8Note
Prevents underflow in BM25STD IDF calculation by clamping totalDocs and adds a regression test validating stable scoring after updates/deletes.
CalculateIDF_BM25insrc/inverted_index.hto clamptotalDocstoMAX(totalDocs, termDocs)to avoid underflow in IDF computation.testBM25STDUnderflowintests/pytests/test_scorers.pyto validate BM25STD scoring does not spike after update/delete flows and remains consistent until GC.Written by Cursor Bugbot for commit c023bc0. This will update automatically on new commits. Configure here.