Classic Highlighter throws IllegalStateException for queries whose rewrite runs a search on its internal one-document reader (RescoreTopNQuery over a doc-values source; filtered or seeded kNN clauses when the token stream comes from term vectors), because that reader reports the highlighted text field's FieldInfo for every field name since 10.5.0 (on 10.3.0 and 10.4.0 the same calls threw UnsupportedOperationException because that reader did not implement getFieldInfos) (known: #7450 / LUCENE-6390, partial overlap) (released)

Finding LFV-1101Area: highlighter / classic Highlighter (WeightedSpanTermExtractor internal reader FieldInfos)Priority: lowImpact: crashNovelty: known upstream

AI-assisted finding, reproduced on Lucene main but not yet independently re-verified, and not yet triaged by a human Lucene committer. This site files nothing upstream.

What it shows

You highlight new RescoreTopNQuery(body:fox, DoubleValuesSource.fromLongField("popularity"), 10) with the classic Highlighter and QueryScorer(q, "body") and expect a fragment with fox marked, because the extractor ignores query parts it cannot use. Instead highlighting throws IllegalStateException 'unexpected docvalues type NONE for field popularity': the extractor rewrites the query on an internal one-document reader whose getFieldInfos() (added by GITHUB#15678 in 10.5.0) describes every field name as the highlighted text field, so the rescorer's doc-values check fails; a filtered kNN clause highlighted from term vectors fails the same way inside FieldExistsQuery.

Expected vs actual

• Expected: The test passes: it asserts the documented behaviour.
• Actual: Highlighting throws IllegalStateException 'unexpected docvalues type NONE for field popularity': the extractor rewrites the query on an internal one-document reader whose getFieldInfos() (added by GITHUB#15678 in 10.5.0) describes every field name as the highlighted text field, so the rescorer's doc-values check fails; a filtered kNN clause highlighted from term vectors fails the same way inside FieldExistsQuery.

Files

• src/org/apache/lucene/search/highlight/TestHighlightSearchExecutingRewrites.java (JUnit test)

Run it

• Tested on Lucene main e1faeba08bde (2026-11-02): reproduced.
• Tested on Lucene main a9779ef3c193 (2026-10-26): 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=$CP:$LUCENE/lucene/highlighter/build/libs/lucene-highlighter-$V.jar
CP=$CP:$LUCENE/lucene/memory/build/libs/lucene-memory-$V.jar
CP=$CP:$LUCENE/lucene/queries/build/libs/lucene-queries-$V.jar
CP=$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.highlight.TestHighlightSearchExecutingRewrites

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 2026-11-03. AI-assisted; not yet triaged by a human Lucene committer. Feedback: open an issue in lucene-ai-bug-hunt.