Multi-dimensional PointInSetQuery skips segments that contain matching points, because its segment early exit uses the lexicographically first and last set points as per-dimension bounds

Finding LFV-475Area: search / points queries (PointInSetQuery segment early exit)Priority: mediumImpact: silent wrong resultsNovelty: new

Finding page for LFV-475

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

What it shows

You subclass PointInSetQuery for a 2-D point field, as Lucene's own tests do, and search for the set {(0,1), (1,0)} in an index whose segment holds one document at (1,0). You expect that document to match, as it does for the one-point set {(1,0)}. Instead, since 10.3.0 the query keeps the first and last set points in sorted order, (0,1) and (1,0), as if they were the set's per-dimension minimum and maximum, concludes from dimension 1 (1 is above the segment's maximum 0) that the segment cannot match, and skips it, so count() is 0 with no error; adding a point to a set can thus remove hits.

The test shows that a 2-D PointInSetQuery for the set {(0,1), (1,0)} skips a segment whose only point is (1,0), because the segment early exit uses the lexicographically first/last set points as per-dimension bounds.

Expected vs actual

Expected count() == 1 (the indexed point is in the set); actual 0 (expected:<1> but was:<0>), with -ea and -da.

Files

• src/org/apache/lucene/search/TestPointInSetQueryMultiDim.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.TestPointInSetQueryMultiDim

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: bulk-overload-precondition-matrix

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.