Eight analysis-factory class javadoc schema examples cannot be used as written: six are not well-formed XML (StopFilterFactory, JapaneseIterationMarkCharFilterFactory, BeiderMorseFilterFactory, OpenNLPTokenizerFactory, OpenNLPLemmatizerFilterFactory, DropIfFlaggedFilterFactory) and two name a class that is not a factory (LimitTokenOffsetFilterFactory's solr.LimitTokenOffsetFilter, PatternTypingFilterFactory's com.example.PatternTypingFilter) (documentation defect)

Finding LFV-931Area: analysis-common, analysis-kuromoji, analysis-phonetic, analysis-opennlp / analysis factories (class javadoc <fieldType> schema examples)Priority: lowImpact: minorNovelty: new

Finding page for LFV-931

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

What it shows

You copy the <fieldType> example from the class javadoc of one of eight analysis factories (StopFilterFactory, for example) into a schema and expect well-formed XML whose elements name registered factories, as the other factory examples do (141 of the 149 example blocks are well-formed; 328 of the 332 elements name a registered factory). Instead six snippets are not well-formed XML (a class attribute with no closing quote after the class name, start tags with no '>' or '/>', a stray '/>' line, and '<-- other filters -->' instead of an XML comment), and two name a class that is not a factory: LimitTokenOffsetFilterFactory's example says solr.LimitTokenOffsetFilter (the filter, not its factory) and PatternTypingFilterFactory's own element says com.example.PatternTypingFilter. The PatternTyping example also lists solr.TokenAnalyzerFilter, a companion filter from a Solr patch that was never committed (a stale reference, not a typo), and its first javadoc sentence describes that companion filter rather than PatternTypingFilter.

The test shows that the StopFilterFactory class-javadoc schema example (copied verbatim) is not well-formed XML; it is one of the eight broken factory examples in this row (documentation defect).

Expected vs actual

Expected: the example parses as XML. Actual: expected well-formed XML, but: Element type "filter" must be followed by either attribute specifications, ">" or "/>". (the <filter> tag is never closed; same with -ea and -da).

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=$CP:$LUCENE/lucene/analysis/common/build/libs/lucene-analysis-common-$V.jar
CP=$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.analysis.core.TestStopFilterFactoryJavadocExample

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: analysis-factory-javadoc-examples-and-resource-files-build-as-documented

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.