A ReferenceManager refresh that throws is reported to its refresh listeners as afterRefresh(false), the same signal as 'nothing changed', so ControlledRealTimeReopenThread.waitForGeneration returns true for a change the current searcher does not contain and LiveFieldValues drops the values it buffered

Finding LFV-312Area: search / ReferenceManager refresh listeners (ControlledRealTimeReopenThread, LiveFieldValues)Priority: lowImpact: silent wrong resultsNovelty: known outside Lucene

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

What it shows

You add, delete or update a document and wait for it with ControlledRealTimeReopenThread.waitForGeneration (or record its value in LiveFieldValues), and the next refresh of the SearcherManager throws, for example because a warm-up query in the SearcherFactory fails or an I/O error hits while the new segment is opened. You expect waitForGeneration to keep waiting or time out, and LiveFieldValues to keep the value, because the old searcher is still current and does not contain the change. Instead ReferenceManager.doMaybeRefresh calls every listener's afterRefresh(false) from a finally block, the same call a refresh that found nothing to do makes, so ControlledRealTimeReopenThread advances its searching generation and wakes the waiters with true, and LiveFieldValues throws away its buffered values.

Expected vs actual

Files

Run it

# 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-src -cp "$CP" $(find src -name '*.java')
javac -d classes-src2 -cp "$CP" $(find src2 -name '*.java')
javac -d classes-src3 -cp "$CP" $(find src3 -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-src:$CP" org.junit.platform.console.ConsoleLauncher \
     execute --select-class org.apache.lucene.search.TestFailedRefreshReportedAsNoChange
java -ea -esa --add-modules jdk.incubator.vector --enable-native-access=ALL-UNNAMED -Dtests.seed=DEADBEEF \
     -cp "classes-src2:$CP" org.junit.platform.console.ConsoleLauncher \
     execute --select-class org.apache.lucene.search.TestFailedRefreshReportedAsNoChange
java -ea -esa --add-modules jdk.incubator.vector --enable-native-access=ALL-UNNAMED -Dtests.seed=DEADBEEF \
     -cp "classes-src3:$CP" org.junit.platform.console.ConsoleLauncher \
     execute --select-class org.apache.lucene.search.TestFailedRefreshReportedAsNoChange

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: nrt-reference-managers

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.