The default SortedSetDocValues terms enum casts the ordinal to int in seekExact(long) and seekExact(term, TermState): on a view with more than 2^31 values a seek by ordinal throws, and from 2^32 values on it can silently land on the wrong term

Finding LFV-449Area: index / sorted-set doc values terms enum (SortedSetDocValuesTermsEnum, the default SortedSetDocValues#termsEnum())Priority: lowImpact: silent wrong resultsNovelty: new

Finding page for LFV-449

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

What it shows

You take the terms enum of a sorted-set doc-values view with more than 2^31 distinct values (for example MultiDocValues.getSortedSetValues over a very large multi-segment index), position it on a term with seekCeil, keep ord() or termState(), and later return with seekExact(ord) or seekExact(term, state); you expect to land on that term again, because sorted-set ordinals are longs and termsEnum() is documented to support ord() and seekExact(long). Instead seekExact(long) stores '(int) ord' (SortedSetDocValuesTermsEnum.java:69), so for ordinals from 2^31 to 2^32-1 it asks the values for a negative ordinal and throws, and for 2^32+5 it silently positions on ordinal 5 and returns that term, with -ea and -da. seekCeil, seekExact(BytesRef), next() and ord() use long arithmetic and are correct; the fix is to drop the cast.

The test shows that the default SortedSetDocValues#termsEnum() casts the ordinal to int in seekExact(long), so on a view with more than 2^32 values seekExact(2^32 + 5) silently lands on ordinal 5.

Expected vs actual

Expected: ord() is 4294967301 after seekExact(4294967301). Actual: expected:<4294967301> but was:<5>, no exception, with -ea and -da.

Files

• src/org/apache/lucene/index/TestSortedSetTermsEnumSeekExactLongOrd.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.index.TestSortedSetTermsEnumSeekExactLongOrd

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.