DoubleValuesSource#toSortableLongDoubleValuesSource() loses its NumericUtils.doubleToSortableLong encoding when rewritten (rewrite() returns the plain toLongValuesSource() cast adapter), so values read after the documented rewrite step, and sorts on it through IndexSearcher, use (long) casts instead

Finding LFV-770Area: core / search value sources (DoubleValuesSource, LongValuesSource adapters)Priority: mediumImpact: silent wrong resultsNovelty: new

Finding page for LFV-770

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

What it shows

You turn a double source into a long source with DoubleValuesSource#toSortableLongDoubleValuesSource(), documented as 'Convert to LongValuesSource by calling NumericUtils#doubleToSortableLong', and, as the LongValuesSource javadoc tells clients to, call rewrite(IndexSearcher) before getValues, or you sort on its getSortField(), which IndexSearcher rewrites for you. You expect the sortable-long encoding, which keeps the order of the doubles; instead rewrite() returns the plain toLongValuesSource() adapter (its toString changes from sortableLong(...) to long(...)), so 0.75, 0.25 and -0.5 all become 0, 2.5 becomes 2 and NaN becomes 0, and a sort over the values {0.75, 0.25, -0.5, 2.5} comes back in docID order with keys 0, 0, 0, 2. The source is correct when it is not rewritten, and the one-line fix is to return inner.rewrite(searcher).toSortableLongDoubleValuesSource().

The test shows that DoubleValuesSource#toSortableLongDoubleValuesSource() loses its NumericUtils.doubleToSortableLong encoding after the documented rewrite(IndexSearcher) step; the rewritten source is the plain (long) cast adapter.

Expected vs actual

Expected: doubleToSortableLong(0.75) = 4604930618986332160 for a document with value 0.75. Actual: 0.

Files

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

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.