Polygon.fromGeoJSON throws NullPointerException instead of its own ParseException 'coordinates should be an array, but got: ...' when "coordinates" (or an element of a MultiPolygon's coordinates) is JSON null or an object, because the error message calls o.getClass() on the null the parser uses for those values (every release since 6.2.0)

Finding LFV-953Area: core / geo GeoJSON parsing (Polygon.fromGeoJSON, SimpleGeoJSONPolygonParser)Priority: lowImpact: wrong errorNovelty: new

Finding page for LFV-953

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 GeoJSON Polygon whose "coordinates" is null or an object, such as {"type":"Polygon","coordinates":null}, or on a MultiPolygon with an object element, {"type":"MultiPolygon","coordinates":[{}]}, and expect the ParseException that the parser has an explicit check for ('coordinates should be an array, but got: ...', 'elements of coordinates array should be an array, but got: ...'), as you get when coordinates is a string, a number or a boolean. Instead java.lang.NullPointerException ('Cannot invoke "Object.getClass()" because "o" is null') escapes, because SimpleGeoJSONPolygonParser stores JSON null and nested objects as Java null and both checks build their message with + o.getClass(). Every other type check in the class builds its message with + o, which is null-safe.

The test shows that Polygon.fromGeoJSON throws NullPointerException instead of its own ParseException when "coordinates" is JSON null ({"type":"Polygon","coordinates":null}) or a MultiPolygon element is an object ([{}]): both 'should be an array, but got: ' messages call o.getClass() on the null the parser stores for null/object values.

Expected vs actual

Expected ParseException (as for a string value). Actual: NullPointerException: Cannot invoke "Object.getClass()" because "o" is null (SimpleGeoJSONPolygonParser.java:208, and :90 for the MultiPolygon line).

Files

• src/org/apache/lucene/geo/TestGeoJSONNullCoordinates.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.geo.TestGeoJSONNullCoordinates

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