TemporalMergePolicy's class javadoc 'Configuration:' example calls .setBaseTimeSeconds(3600), a method that does not exist: the setter was renamed to setBaseTimeInSeconds(long) during review of #15620 and the example kept the old name, so it has not compiled on any release (documentation defect)

Finding LFV-1020Area: core / index merge policy (TemporalMergePolicy class javadoc example)Priority: lowImpact: minorNovelty: new

Finding page for LFV-1020

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

What it shows

The TemporalMergePolicy class javadoc shows, under 'Configuration:', how to build the policy with a fluent chain: setTemporalField("timestamp"), setBaseTimeSeconds(3600), setMinThreshold(4), setMaxThreshold(8) and setCompactionRatio(1.2), then passes it to IndexWriterConfig.setMergePolicy. The class has no setBaseTimeSeconds method: its setter is setBaseTimeInSeconds(long), renamed on a reviewer's suggestion while #15620 was in review, so the copied example fails with javac 'cannot find symbol: method setBaseTimeSeconds(int)'. With setBaseTimeInSeconds(3600) the example compiles and the getters return exactly the commented values, so only the javadoc is wrong.

Expected vs actual

• Expected: The copied example compiles.
• Actual: One javac error, cannot find symbol: method setBaseTimeSeconds(int), location: class TemporalMergePolicy, with assertions on and off, on main and on the 10.6.0 jars.

Files

• src/org/apache/lucene/index/TestTemporalMergePolicyJavadocExample.java (JUnit test)

Run it

• Tested on Lucene main e1faeba08bde (2026-11-02): still reproduces.
• Tested on Lucene main 645d4fe14a20 (2026-10-28): reproduced.
• 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.index.TestTemporalMergePolicyJavadocExample

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).

Files shown on the finding page

• TestTemporalMergePolicyJavadocExample.java

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.