Polygon.fromGeoJSON rejects a valid GeoJSON Feature whose properties (or another non-geometry member object) contain a member named "type", throwing ParseException 'can only handle type ... but got <value>' (every release since 6.2.0)
Finding LFV-562Area: core / geo GeoJSON parsing (Polygon.fromGeoJSON, SimpleGeoJSONPolygonParser)Priority: lowImpact: wrong errorNovelty: 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 call Polygon.fromGeoJSON on a standard GeoJSON Feature whose geometry is a single Polygon and whose properties contain an ordinary data member named "type", for example {"type": "Feature", "geometry": {...Polygon...}, "properties": {"type": "multipolygon"}}, and expect the polygon back, because the javadoc accepts a Polygon 'optionally embedded under a "type: Feature"' and GeoJSON allows any JSON object as properties. Instead it throws ParseException 'can only handle type FeatureCollection (if it has a single polygon geometry), Feature, Polygon or MultiPolygon, but got multipolygon' ('type should be a string, but got: 3.0' for {"type": 3}), because the parser reads every "type" member outside crs as a GeoJSON object type, wherever it sits, while it reads "coordinates" only at geometry positions. The same Feature without the "type" property parses, and a "coordinates" key inside properties is ignored.
The test shows that Polygon.fromGeoJSON rejects a GeoJSON Feature whose properties object contains an ordinary member named "type" ({"type": "x"}).
Expected vs actual
Expected: the same polygon as the bare Polygon geometry. Actual: ParseException "can only handle type FeatureCollection ..., Feature, Polygon or MultiPolygon, but got x", with -ea and -da.
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=$CP:randomizedtesting-runner-2.9.2.jar:junit-4.13.2.jar:hamcrest-3.0.jar # test-framework dependencies (Maven Central)
CP=$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.geo.TestGeoJSONFeatureTypePropertyGradle 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.