Float/Byte/Float16VectorSimilarityQuery.visit() never visits the filter, so the filter's clauses escape IndexSearcher's cumulative maxClauseCount check and QueryVisitor term collection

Finding LFV-916Area: search / vector similarity queries (AbstractVectorSimilarityQuery QueryVisitor traversal; consumers: IndexSearcher's cumulative clause limit, QueryVisitor.termCollector, RamUsageEstimator.sizeOf(Query))Priority: lowImpact: minorNovelty: new

Finding page for LFV-916

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 BooleanQuery(MUST a 600-term disjunction, MUST FloatVectorSimilarityQuery.Adaptive(field, target, 0f, filter = another 600-term disjunction)), 1,200 term clauses in all, and search it with the default maxClauseCount of 1024. You expect TooManyNestedClauses, which you do get when the same 600 clauses are a sibling FILTER clause, because the check counts 'total clauses cumulatively in all of its children' and Query#visit is documented to visit 'any child queries'. Instead the search runs: AbstractVectorSimilarityQuery.visit only calls visitor.visitLeaf(this), so the filter, which stays in the rewritten query and is executed in createWeight, is checked only on its own; ByteVectorSimilarityQuery and Float16VectorSimilarityQuery behave the same, and QueryVisitor.termCollector returns none of the filter's terms.

The test shows that FloatVectorSimilarityQuery.visit() never visits its filter, so IndexSearcher's cumulative maxClauseCount check does not count the filter's clauses.

Expected vs actual

Expected TooManyNestedClauses for BooleanQuery(MUST 600-term disjunction, MUST FloatVectorSimilarityQuery.Adaptive(filter = 600-term disjunction)), 1,200 clauses over the default limit of 1024; actual: no exception (Expected exception TooManyNestedClauses but no exception was thrown), with -ea and -da.

Files

• src/org/apache/lucene/search/TestVectorSimilarityQueryFilterClauseCount.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.search.TestVectorSimilarityQueryFilterClauseCount

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.