HTMLStripCharFilter drops the visible text after a tag when a quoted attribute value ends with whitespace, a name and '=' (title="a b=", alt="x y ="): the scanner re-reads the value's closing quote as the opening quote of a new attribute value, so the tag runs on to the next quote of the same kind; the GITHUB#15754 fix (#15756) covers only the shape without whitespace

Finding LFV-290Area: analysis / HTMLStripCharFilter (JFlex grammar: OpenTagAttribute, EventAttribute, OpenTagContent)Priority: mediumImpact: silent wrong resultsNovelty: known upstream

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

What it shows

You strip '<p title="a b=">one</p> two <p title="c">three</p>' with HTMLStripCharFilter and expect the words 'one two three', as the GITHUB#15754 fix (#15756, 10.5.0) now gives for title="ab=". Instead only 'three' comes out: the scanner may treat the value's opening quote as plain tag text, then read ' b=' plus the value's closing quote as the start of a new quoted value, which runs to the next double quote in the document, so the tag swallows 'one two' and that text is never indexed. No error is raised, and the #15754 input itself is handled correctly on main.

Expected vs actual

• Expected: The test passes: it asserts the documented behaviour.
• Actual: Only 'three' comes out: the scanner may treat the value's opening quote as plain tag text, then read ' b=' plus the value's closing quote as the start of a new quoted value, which runs to the next double quote in the document, so the tag swallows 'one two' and that text is never indexed.

Files

• src/org/apache/lucene/analysis/charfilter/TestHTMLStripAttributeReparse.java (JUnit test)

Run it

• Tested on Lucene main e1faeba08bde (2026-11-02): still reproduces.
• Tested on Lucene main ea57360912ed (2026-10-24): 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/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.charfilter.TestHTMLStripAttributeReparse

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.