Formal models and scripts: parallel-reader-advertises-index-sort-of-shadowed-sort-field

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

• ParallelLeafReader and ParallelCompositeReader advertise a sub-reader's index sort even when an earlier, unsorted sub-reader serves the sort field, so sorted searches and index-sort range shortcuts return wrong hits and IndexWriter.addIndexes writes a segment that breaks its declared index sort (finding LFV-981; repro · finding page)

Files

• parallelleafreader-advertises-sort-of-shadowed-sort-field/model/compare_fix.py (used for LFV-981)
• parallelleafreader-advertises-sort-of-shadowed-sort-field/model/drop_breakdown.py (used for LFV-981)
• parallelleafreader-advertises-sort-of-shadowed-sort-field/model/violation_smt.py (used for LFV-981)

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.