index/index.js:1070:Mw seals a commit's parents with i < 16, silently dropping
the 17th+ parent of an octopus merge. The real constraint — CPAR's ord
lives in a 4-bit vnib (INDEXES.mkd) — is stated nowhere at the site: no named
constant, no ticket, and INDEXES.mkd's CPAR entry says "one row per parent"
with no cap. A dropped parent falsifies the DAG lite log walks. Found in
the 2026-08-21 review.
2026-09-18 index review: not theoretical — ~/src/linux carries a commit with
66 parents, so 50 of its CPAR edges are absent (index/index.js:1152:Wt at
///bee#8cb69a0); the rev derivation at :1136 still uses all 66, so only the
DAG is wrong. Keep minting rows past 15 with ord clamped at 15: ord only
orders the first parent and parentsOf dedupes anyway.
Name the constant, document the cap where CPAR is specified, and either warn at seal time or extend past 16 the way REV-PARS rides a second row.