Slicing an MMapDirectory clone with read advice after its original is closed throws AssertionError instead of AlreadyClosedException (PosixNativeAccess.madvise wraps the closed-arena IllegalStateException in an Error)

Finding LFV-129Area: store / MMapDirectory read advice (PosixNativeAccess madvise, MemorySegmentIndexInput slices of closed inputs)Priority: lowImpact: wrong errorNovelty: 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 clone an MMapDirectory input, close the original, and then slice the clone with an IOContext whose read advice is RANDOM or SEQUENTIAL (for example with setReadAdvice(ADVISE_BY_CONTEXT) and IOContext.DEFAULT.withHints(DataAccessHint.RANDOM)); like reading from the clone, which throws AlreadyClosedException, this should report that the input is closed. Instead the slice call throws java.lang.AssertionError: java.lang.IllegalStateException: Already closed, because PosixNativeAccess.madvise wraps every Throwable of the native posix_madvise call in an AssertionError before MemorySegmentIndexInput.advise() can turn the closed-arena IllegalStateException into AlreadyClosedException. It is an explicit throw, not an assert, so it happens with assertions disabled too; no data is read or written wrongly.

Expected vs actual

Expected: The test passes: it asserts the documented behaviour.
Actual: The slice call throws java.lang.AssertionError: java.lang.IllegalStateException: Already closed, because PosixNativeAccess.madvise wraps every Throwable of the native posix_madvise call in an AssertionError before MemorySegmentIndexInput.advise() can turn the closed-arena IllegalStateException into AlreadyClosedException.

Files

src/org/apache/lucene/store/TestCloneSliceWithAdviceAfterClose.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=$CP:randomizedtesting-runner-2.9.2.jar:junit-4.13.2.jar:hamcrest-3.0.jar   # test-framework dependencies (Maven Central)
CP=$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.store.TestCloneSliceWithAdviceAfterClose

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 2026-11-03. AI-assisted; not yet triaged by a human Lucene committer. Feedback: open an issue in lucene-ai-bug-hunt.