Group Access Inheritance: Collection → Subcollection

Area: collections / access control Raised during: Spike 3 Jira: (add when available) Priority: High Status: ✅ SUPERSEDED by ADR 011 (Accepted 2026-06-18) — Option D (entity-ref + custom hooks) ratified; visibility + membership inheritance land in Sprint 1 Step 1b (task 1b.2). This note remains for historical context.

Problem

In Group 3.x with the entity reference nesting approach (Option A from the companion deferred note), subcollections are independent Group entities. A node's access is determined by the groups it directly belongs to.

Consequence: If a collection is restricted (anonymous role has no view permissions), that restriction does not automatically apply to nodes in the collection's subcollections. Each subcollection's access must be configured independently.

Example: - "Buddhist Texts" collection — restricted - "Tibetan Sutras" subcollection inside it — public by default if anonymous role has view permissions on subcollection group type - A node in "Tibetan Sutras" would be publicly visible even if the parent collection is restricted

Resolution (2026-06-12)

D7 baseline confirmed — full inheritance model: 1. Visibility: private parent → private subcollection by default; subcollection can independently override to public 2. Membership: subcollection inherits all parent collection members; additional members can be added to subcollection independently

ggroup and subgroup investigated: Both handle membership/role inheritance (partially addressing requirement 2) but neither propagates group-level visibility (public/private) from parent to child (requirement 1 unaddressed by either).

Recommended approach: Entity reference field (proven in Spike 3) + custom hooks for both inheritance requirements. See group-subgroup-nesting-approach.md — Option D for full details including membership sync edge cases.

Impact

This decision affects Phase 3 (collections implementation) and the access control section of the migration plan. If inheritance is required and addressed via custom code rather than a contrib module, the implementation effort for Phase 3 increases.