The Lucene 10.6.0 release notes (CHANGES.txt in the 10.6.0 RC1 and in main's copy of the 10.6.0 section) say StableTflSimilarity 'also supports k3 query-term frequency saturation', but 10.6.0 has no k3: the 10.6 backport left k3 out and dropped the sentence on review request, and an unrelated later backport put the sentence back (documentation defect, released in 10.6.0)

Finding LFV-948Area: release notes / lucene/CHANGES.txt 10.6.0 New Features (GITHUB#16243 entry) x search / similarities (StableTflSimilarity)Priority: lowImpact: minorNovelty: new

Finding page for LFV-948

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

What it shows

You read the Lucene 10.6.0 release notes, whose GITHUB#16243 entry says StableTflSimilarity 'also supports k3 query-term frequency saturation', and write new StableTflSimilarity(1.2f, 0.917f, 7f) against the 10.6.0 jar. You expect it to compile, as it does on main; instead javac finds no (float, float, float) constructor and no getK3(), because the 10.x backport (#16322) deliberately left k3 out ('remove k3 which isn't in 10') and, on the feature author's review request, also dropped the k3 sentence, which a later, unrelated backport commit (3a75616c943, the #16300 backport) put back. The sentence ships in the RC1 source release's CHANGES.txt and Changes.html and is also in main's copy of the 10.6.0 section.

The test shows that the Lucene 10.6.0 CHANGES entry for GITHUB#16243 (RC1 CHANGES.txt:57, and main's copy of the 10.6.0 section at CHANGES.txt:507) says StableTflSimilarity 'also supports k3', but the 10.6.0 class has no k3 constructor; main's class has one, so the test passes on main and fails on the 10.6.0 RC1 code.

Expected vs actual

(10.6.0 RC1, branch_10_6 4ae946e5a9b) expected a StableTflSimilarity(float k1, float c, float k3) constructor; actual constructors: StableTflSimilarity(float, float) and StableTflSimilarity().

Files

src/org/apache/lucene/search/similarities/TestStableTflSimilarityK3.java (JUnit test)

Run it

Tested on Lucene main e1faeba08bde (2026-11-02): still reproduces.
Tested on Lucene branch_10_6 4ae946e5a9b9 (2026-10-26): reproduced on 10.6.0-SNAPSHOT jars built at this commit.
Recorded outcome of run 1 on Lucene branch_10_6 4ae946e5a9b9: 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.similarities.TestStableTflSimilarityK3

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.