RescoreTopNQuery passes negative DoubleValuesSource values through as negative scores, so a top-k BooleanQuery that ORs it with another clause silently returns no hits

Finding LFV-1015Area: search / rescoring (RescoreTopNQuery scores, consumed by MaxScoreBulkScorer dynamic pruning)Priority: mediumImpact: silent wrong resultsNovelty: new

Finding page for LFV-1015

AI-assisted finding, confirmed by automated checks, not yet triaged by a human Lucene committer. This site files nothing upstream.

What it shows

You index 10 documents with a numeric doc-values field v = -2..-11 and run BooleanQuery(SHOULD RescoreTopNQuery(MatchAllDocsQuery, DoubleValuesSource.fromLongField("v"), 1), SHOULD MatchAllDocsQuery) with searcher.search(q, 10), expecting all 10 documents, since each one matches the MatchAllDocsQuery clause and count(q) is 10. Instead it returns 0 hits and totalHits 0. RescoreTopNQuery copies the raw value -2 into the score, although Lucene requires non-negative scores (LUCENE-7996) and FunctionScoreQuery maps negative values to 0, so the clause reports a max score of -2, the two clauses' max scores sum to -1, below the initial minimum competitive score of 0, and MaxScoreBulkScorer skips the whole window as if no document could compete.

The test shows that BooleanQuery(SHOULD RescoreTopNQuery(MatchAllDocsQuery, DoubleValuesSource.fromLongField("v"), 1), SHOULD MatchAllDocsQuery) returns no hits from search(q, 10) on a one-document index with v = -2: the negative value becomes a negative score and max score (-2), the clauses' max scores sum to -1, and MaxScoreBulkScorer skips every document.

Expected vs actual

Expected: 1 hit (the document matches the MatchAllDocsQuery clause); actual: expected:<1> but was:<0>, with -ea and -da.

Files

• src/org/apache/lucene/search/TestRescoreTopNQueryNegativeValues.java (JUnit test)

Run it

• Tested on Lucene main e1faeba08bde (2026-11-02): still reproduces.
• Tested on Lucene main 645d4fe14a20 (2026-10-28): reproduced.
• Recorded outcome of run 1 on Lucene main 645d4fe14a20: 1 test(s) run, 1 failed.
• How to read the outcome: a failing test is the finding reproducing (the failure message states expected against actual).
• Seeds: a rerun with the same seed replays the same random choices. Assertions off (-da -dsa -Dtests.asserts=false) is the production-like setting.

# Lucene checkout at the tested commit, built with: ./gradlew --no-daemon assemble   (JDK 25)
LUCENE=/path/to/lucene; V=12.0.0-SNAPSHOT
CP=$LUCENE/lucene/core/build/libs/lucene-core-$V.jar
CP=$CP:$LUCENE/lucene/codecs/build/libs/lucene-codecs-$V.jar
CP=$CP:$LUCENE/lucene/test-framework/build/libs/lucene-test-framework-$V.jar
CP=$CP:randomizedtesting-runner-2.9.2.jar:junit-4.13.2.jar:hamcrest-3.0.jar   # test-framework dependencies (Maven Central)
CP=$CP:junit-platform-console-standalone-6.1.3.jar   # JUnit Platform console launcher (Maven Central)

javac -d classes -cp "$CP" $(find src -name '*.java')

# run 1: assertions on, seed DEADBEEF
java -ea -esa --add-modules jdk.incubator.vector --enable-native-access=ALL-UNNAMED -Dtests.seed=DEADBEEF \
     -cp "classes:$CP" org.junit.platform.console.ConsoleLauncher \
     execute --select-class org.apache.lucene.search.TestRescoreTopNQueryNegativeValues

Gradle alternative: copy the test into the matching module's src/test/ tree of the checkout and run ./gradlew -p lucene/<module> test --tests <class> -Ptests.seed=<seed> (add -Ptests.asserts=false for a run without assertions).

Formal models and scripts this finding's part of the hunt used: rescoretopn-negative-rescore-values-maxscore-hang

Feedback

Open an issue in lucene-ai-bug-hunt. Please do not open issues or pull requests in apache/lucene about this finding unless a Lucene committer agrees it should be filed.

Snapshot of 2026-11-04. AI-assisted; not yet triaged by a human Lucene committer. Feedback: open an issue in lucene-ai-bug-hunt.