Formal models and scripts: wand-blockmax-bounds

Tools: Python

These are the working models and scripts this part of the hunt used. Some encode the code as it is (a counterexample is the expected result), others a fixed or correct variant; read the header comment of each file. Paths inside them were replaced by placeholders such as $LUCENE (a Lucene checkout) and $WORK.

Findings

• ScorerUtil.minRequiredScore returns NaN when the minimum competitive score is +Infinity, so block-max conjunctions and MaxScore disjunctions drop documents that score +Infinity (finding LFV-104; repro · finding page)
• WANDScorer mishandles a minimum competitive score of +Infinity: an assertion fails with -ea, and with -da it prunes documents that score +Infinity (finding LFV-113; repro · finding page)

Files

• model/wand_lemmas.py (used for LFV-104, LFV-113)

How to run

• Python: python3 <file>.py; scripts that import z3 need the z3-solver package.

Snapshot of 2026-11-04. AI-assisted; not yet triaged by a human Lucene committer. Feedback: open an issue in lucene-ai-bug-hunt.