- FormFieldBindingMergeStrategy::nullWinnerBehaviour() and
isValidForScalarTargets() encode the per-strategy null-winner matrix
(RFC Q7) and the collection-only restriction (RFC V1).
- ResolvedBinding/BindingApplicationResult/BindingPassResult readonly
DTOs for the binding pipeline. Construction-time validation for
trust level. Apply-status derived from result aggregate.
Note: the existing enum is named FormFieldBindingMergeStrategy (not
MergeStrategy as the prompt sketched). Methods added to it directly.
Refs: RFC-WS-6.md §3 (Q4, Q7), §4 (V1)
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
WS-5a commit 1 of 4 per ARCH-CONSOLIDATION-ADDENDUM-2026-04-24 Q3.
Creates the relational home for what was form_fields.binding JSON and
form_field_library.default_binding JSON. Owner discriminator is polymorphic
morph (owner_type/owner_id) — the pattern the rest of WS-5 (5b validation_rules,
5d options) will reuse.
Migration backfills rows from both JSON sources in a single transaction and
is genuinely reversible (rollback reconstructs the JSON). Old columns remain
in place until commit 3 has switched all readers.
Pattern B (binding=null) is represented by absence of row. mode enum covers
entity_owned / mirrored only.
Cascade on owner delete via observer — bindings are physical state, not
historical audit. FormFieldBindingScope enforces multi-tenancy via UNION over
both owner chains (form_field → schema → org OR form_field_library → org) —
Q2's declarative tenantScopeStrategy() can't walk morph parents.
Tests: migration forward/back, morph relation, cascade observer, scope
isolation, enum coverage.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
