GeoPath.computeDistance with DistanceStyle.LINEAR_SQUARED or NORMAL_SQUARED on a path of width > 0 (GeoStandardPath) returns the fourth power of the distance instead of its square for points inside a path segment, because the segment's result is converted back from aggregation form twice (regression since 9.5.0)
Finding LFV-271Area: spatial3d / geom path distances (GeoStandardPath component tree: PathSegment, BaseSegmentEndpoint, PathNode; DistanceStyle aggregation forms)Priority: lowImpact: minorNovelty: new
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 a path with GeoPathFactory.makeGeoPath and a width > 0 and call computeDistance with DistanceStyle.LINEAR_SQUARED (or NORMAL_SQUARED), expecting the square of the LINEAR (or NORMAL) path distance, which is what DistanceStyle's 'convert to aggregation form, aggregate, convert back' contract gives and what end-cap points, the zero-width path and Lucene 9.4.2 return. For a point inside a path segment you get the square of that value instead: 0.00803 rather than 0.0896 for a point whose LINEAR distance is 0.299, so the value jumps about 6x across a segment's end cutoff plane and can rank a farther point ahead of a nearer one. The cause is a leftover conversion from the 2022 path refactor: PathSegment.distance already converts its result back from aggregation form, and GeoStandardPath.distance converts the component tree's result back a second time.
The test shows that GeoPath.computeDistance(DistanceStyle.LINEAR_SQUARED, p) on a width-0.1 path (a GeoStandardPath) for a point inside the path segment.
Expected vs actual
Expected: LINEAR^2 = 0.0896. Actual (-ea and -da): 0.00803 = LINEAR^4, the result is converted back from aggregation form twice.
Files
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/spatial3d/build/libs/lucene-spatial3d-$V.jar
CP=$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.spatial3d.geom.TestGeoPathSquaredDistanceGradle 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 2026-11-04. AI-assisted; not yet triaged by a human Lucene committer. Feedback: open an issue in lucene-ai-bug-hunt.