Formal models and scripts: twin-family-static-diff

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

• MutableValueFloat and MutableValueDouble equals() compare with ==, so a NaN value is not equal to itself and grouping by a float or double function puts NaN documents into empty groups (4.0.0 to 10.5.2) or throws IllegalArgumentException (main and, by reading, 10.6.0) (finding LFV-427; repro)

Files

• mutablevalue-float-double-equals-uses-primitive-eq/model/mutablevalue_fp_equality.py (used for LFV-427)

How to run

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

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