reikhelm/.dev/2026-05-28-procgen-map-core/state/smell-ledger.md

Smell Ledger — reikhelm

Patterns surfaced by implementers/reviewers. Format: pattern — where found — where fixed — where it remains.

• range() i32 overflow for astronomically large spans — rng.rs range does lo + self.below(span) as i32; spans ≳2³¹ could overflow. UNREACHABLE in a grid-coordinate generator (spans are tiny). Logged, not fixed — fixing would be over-engineering for the domain. Revisit only if a pass ever needs huge ranges.
• Map equality workaround (RESOLVED) — map.rs originally compared maps via serialized-JSON strings because Map wasn't Eq. Fixed at source by deriving PartialEq/Eq on Grid + Map (commit 8c4ef2e). Downstream (T6/T12) should use assert_eq! on Maps, not reinvent the workaround.
• Watch in passes: Point/Tile derive Hash — using a HashSet for flood-fill visited membership is fine (determinism only breaks on HashMap/HashSet iteration order). If any pass iterates a HashMap/HashSet to produce output, that's a determinism bug — flag it.