Formal models and scripts: dismax-synonym-combined

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

• SynonymQuery adds up boosted term frequencies in float in heap order, so identical documents can score differently and explain() can differ from the hit score; with more than 2^24 occurrences in one field a score can exceed getMaxScore() (finding LFV-272; repro · finding page)

Files

• synonym-scorer-float-freq-sum/model/synonym_freq_lemmas.py (used for LFV-272)

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.