Formal models and scripts: collector-managers-remaining

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

• Grouping LongRangeFactory and DoubleRangeFactory give the last range below max the full width, so its reported group bounds run past max and overlap the range for values >= max (finding LFV-407; repro · finding page)
• Grouping DoubleRangeFactory picks a value's bucket and computes that bucket's bounds with separately rounded arithmetic, so with a decimal width such as 0.1 the returned range can exclude the value and adjacent ranges leave gaps or overlap (DoubleRangeFactory(0, 0.1, 10).getRange(0.6) = DoubleRange(0.5, 0.6)) (finding LFV-412; repro · finding page)
• Grouping DoubleRangeFactory gives the below-min group the lower bound Double.MIN_VALUE (4.9E-324, the smallest positive double) instead of the most negative value, so that group's DoubleRange label does not contain its own members (finding LFV-411; repro · finding page)

Files

• doublerangefactory-below-min-label-double-min-value/model/range_factory.py (used for LFV-411)
• doublerangefactory-label-boundaries-rounding-gap/model/range_factory.py (used for LFV-412)
• range-factory-final-range-crosses-max/model/range_factory.py (used for LFV-407)

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.