IntervalQuery equals/hashCode ignore the score function (pivot/exp), so BooleanQuery merges two differently scored IntervalQuery clauses into one and returns wrong, clause-order-dependent scores

Finding LFV-292Area: queries / intervals (IntervalQuery equality, consumed by BooleanQuery and DisjunctionMaxQuery duplicate-clause handling)Priority: lowImpact: silent wrong resultsNovelty: new

Finding page for LFV-292

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

What it shows

You build two IntervalQuery objects on the same field and term that differ only in their scoring pivot, new IntervalQuery("f", Intervals.term("a"), 1f) and the same with 100f, and combine them as SHOULD clauses of a BooleanQuery. You expect the document 'a b a c a' to score the sum of the two clause scores, 0.75 + 0.0291 = 0.7791, because the javadoc documents pivot and exp as parameters that change the score. Instead IntervalQuery.equals/hashCode compare only the field and the intervals source, so the two queries are equal, BooleanQuery.rewrite merges them into the single clause (f:a)^2.0 that keeps only the first clause's pivot, and the document scores 1.5; with the clauses swapped it scores 2 x 0.0291 = 0.0583, so the score also depends on clause order.

The test shows that two IntervalQuery SHOULD clauses that differ only in their pivot (1 vs 100) are treated as equal and merged by BooleanQuery, so the disjunction is scored with the first clause's pivot twice.

Expected vs actual

Expected the sum of the two clause scores 0.509901 (0.5 + 0.0099); actual 1.0 (expected:<0.509901> but was:<1.0>), with -ea and -da.

Files

• src/org/apache/lucene/queries/intervals/TestIntervalQueryDifferentPivotsDisjunction.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=$CP:$LUCENE/lucene/queries/build/libs/lucene-queries-$V.jar
CP=$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.queries.intervals.TestIntervalQueryDifferentPivotsDisjunction

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).

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 2026-11-03. AI-assisted; not yet triaged by a human Lucene committer. Feedback: open an issue in lucene-ai-bug-hunt.