0455 — Rules pack defaults without a scope, registered fact sources, list floors, and sections without a base pack

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Context

Commerce found four gaps. RuleSetService.open and seedPack need a ScopeRef, so a module cannot decide with a pack’s default rule set (returns policy, COD) before a scope has seeded its own. Rules.create freezes the fact sources, so an edition loaded after the consumer cannot contribute one (shipping’s delivery promise, the OMS busy rules). FloorBound is min or max, so a list a scope may add to but never drop from (refused goods) cannot be a legal floor. resolvePack refuses a market without a base pack, and the OS base packs do not exist yet (STA-848), so Commerce resolves its sections with its own pickCommercePack and market-code nesting. Wave 12 already has seedPack on a scope; the other three gaps were open as filed.

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Decision

1. A pack’s default rule set opens without a scope. packRuleSetOf(pack, key, rules) (the . entry, isomorphic) parses a RuleSetPack$ document, finds template key, refuses one of another consumer, and checks its condition and outcomes against the consumer’s Rules, returning a RuleDocument that evaluate and decide take. RuleSetService.openDefault(pack, key, rules) returns the same as a RuleSetRevision numbered 0, with the pack version as seedVersion and never published. Nothing is stored and no platform scope row stands in for it; seedPack(scope, …) remains the way a default becomes a scope’s own record. decide still applies the floors.
2. Fact sources are registered after create. Rules.register(...sources) is the registration hook: each source is checked as create checks one (camelCase keys, declared types, enum values), a source key already registered is refused, and a call is all or nothing. Rules stays frozen except for its source list and field map; nothing is ever replaced or removed. Until a source is registered, a condition naming its fields is field_unknown at save time, as before. An edition registers at module init, before it saves or evaluates a rule naming its fields, and ConditionFieldService.sync runs after it.
3. FloorBound.List, the list floor. A list floor’s value is a list (MarketPack$ refuses another value). A value keeps every item of the floor and may add more. overlayFloorIssues reports an overlay list that drops an item as floor_loosened. In rules, a list outcome parameter may name a floor; crossedFloor moves a list missing items to the list plus the missing items (past_floor), and throws for a list floor on a non-list parameter, a min/max floor on a list, or a list floor that is not strings (a pack bug).
4. Sections without a base pack. ResolveOptions.requireBase (default true): when false, a market with no fitting base pack answers with its requested sections alone, on its pin or else the highest version, and its parent is its market code without the last segment (eu-de under eu). The asked-for market still needs a base or a section, or PackNotFoundError; a base pack, when present, is used as always and its extends is followed. The default stays true, so a missing platform base pack is still refused where it should exist.
5. pickPack is public on the . entry, so a product picks one section version under the same pin and status rules resolvePack uses. compareVersions stays internal.

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Consequences

• @stackra/settings’ crossesFloor compares min and max only; a list floor reaching it is not refused there until the settings owner adds the list case (a follow-up, outside this batch). Every bound comparison must handle all three bounds.
• Rules.sources is now a getter returning a frozen copy; reading it is unchanged.
• Commerce can drop pickCommercePack and commerceChain (setup) for pickPack and requireBase: false, read the returns and COD defaults with openDefault, and register edition fact sources with register.
• A list floor may grow a list past the 100 strings a list parameter takes; a pack author keeps floor lists short.

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Alternatives

• A platform scope row for pack defaults. Rejected: it puts a fake scope under row-level security and a seed to maintain per pack version, for a value that is pure pack data.
• Rebuilding Rules with the extra sources (Rules.extend returning a new value). Rejected: every holder of the consumer’s Rules constant would need the new value; the registry is one per consumer.
• Market-code nesting always. Rejected: base packs declare extends, and an overlay whose parent is not its code prefix must follow the data; nesting by code is only the fallback for a market with no base pack.

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Supersedes and sources

Supersedes nothing; amends ADR 0370 (decisions 3, 4 and 6) and ADR 0331 (decision 2). Sources: Commerce apps/docs/src/docs/build/module-catalogue.mdx (Stackra gaps: rules, market-packs), services/catalogue/src/modules/setup/SPEC.md, services/fulfilment/src/modules/shipping/SPEC.md; STA-848; owner decision D2.