Expressions: !, &&, || and ?: keep only the low 32 bits of a bitwise/shift result or hex/octal literal, so a non-zero value such as 1 << 32 or 0x100000000 counts as false

Finding LFV-181Area: expressions / JavascriptCompiler code generation (boolean operators on long-typed operands: bitwise and shift results, hex and octal literals)Priority: lowImpact: silent wrong resultsNovelty: new

Finding page for LFV-181

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

What it shows

You compile a Lucene expression that tests a high bit of a long field, such as '(flags & 0x100000000) ? 10 : 1' over a NumericDocValuesField with flags = 2^32 + 1, and expect 10, because 'flags & 0x100000000' evaluates to 4294967296 and '(flags & 0x100000000) != 0' is 1. Instead you get 1: the compiler asks for the operand of !, &&, || and ?: as a 32-bit int and narrows a long-typed operand (the result of & | ^ ~ << >> >>>, or a hex/octal literal) by keeping only its low 32 bits, so every non-zero value whose low 32 bits are zero counts as false. The same number is true when written as the decimal literal 4294967296, as a variable or as '((1 << 32) + 0)', but false as '0x100000000' or '(1 << 32)'.

The test shows that a Lucene expression tests a long-typed condition by keeping only its low 32 bits, so the non-zero value (1 << 32) = 4294967296 counts as false.

Expected vs actual

Expected: (1 << 32) ? 1 : 0 = 1. Actual: 0 (expected:<1.0> but was:<0.0>), with -ea and -da.

Files

• src/org/apache/lucene/expressions/js/TestBooleanOperandHighBits.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: 4 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=$CP:$LUCENE/lucene/expressions/build/libs/lucene-expressions-$V.jar
CP=$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.expressions.js.TestBooleanOperandHighBits

The module(s) expressions also need their third-party runtime jars; ./gradlew -p lucene/<module> dependencies lists them.

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: expressions-compiler

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.