18000x · 02 — Template Versioning Gap Matrix

Method

Live discovery first (per 12000x L1 / 15000x L1 lessons). Surveyed:

• pg_proc for fn_iu_*template* / fn_iu_*version*
• information_schema.tables for *template* / *version* / *registry*
• iu_piece_collection.collection_key for version suffix patterns (/v1, /v2)
• iu_collection_template_registry columns (mig 031) for version fields

Live findings

Already LIVE_READY (no work needed)

Capability	Lives where
Template marker	iu_collection_template_registry (mig 031)
Template→instance lineage	iu_collection_template_instance_lineage (mig 031)
Template registry view	v_iu_product_template (mig 031)
Template instance view	v_iu_product_template_instance (mig 031)
Template register DOT	dot_iu_register_template (15000x)
Lineage record DOT	dot_iu_record_template_instance (15000x)
Template+Instance mechanism	fn_iu_compose iu_id-reuse branch (12000x Phase F)
Text-as-code roundtrip	cutter_agent/iu_core/text_as_code.py (12000x)
Manifest digest invariant	fn_iu_collection_manifest_refresh (mig 015)

GAPs to close in 18000x

#	Gap	Severity	Resolution
G1	No durable version chain (predecessor pointer + family identity)	High	Migration 032 sidecar iu_collection_template_version
G2	No queryable version chain view	Med	v_iu_template_version_chain
G3	No register-version DOT	High	dot_iu_register_template_version + fn_iu_collection_register_template_version
G4	No retire-version DOT	Med	dot_iu_retire_template_version + fn_iu_collection_retire_template_version
G5	No cross-template observability view consolidating template + version + instance + digest signals	High	v_iu_template_observability
G6	No template mutation invariant policy documented	Med	05-mutation-invariants-proof.md
G7	No bulk instance generation at scale > 1	Med	ops/.../iu_core_18000x_bulk_instances.sql (3 instances)
G8	No bulk text-as-code export driver	Med	cutter_agent/iu_core/bulk_template_export_18000x.py
G9	No internal LIVE event proof (only dry-run at 15000x)	Med	ops/.../iu_core_18000x_piece_event_live_proof.sql (BEGIN/ROLLBACK)
G10	No auto-instantiate-from-event mechanism shown	Med	ops/.../iu_core_18000x_auto_instantiate_proof.sql (sandbox)

Carry-forward (NOT productized in 18000x, intentional)

Item	Why deferred	Next macro
Live (durable) non-dry-run external delivery	Requires external worker beyond constitution scope	≥19000x
Auto-instantiate daemon/cron	Constitution explicitly forbids; sandbox proof only	≥19000x
Template piece mutation propagation policy code	Documented as invariant; mechanism is explicit v(N+1) compose	19000x
Retention enable	Requires 30-day soak per L1 carry-forward	≥17000x (operator)
PR #669 merge / Nuxt deploy	External owners	external
Birth-gate PILOT noise (P-pub1/P-pub2 warnings)	Carry-forward from 15000x — noise only, not failures	≥19000x
File template (tpl:file:status-report/v1) version chain enrolment	Single-version family; operator-opt-in via dot_iu_register_template_version when v2 ships	19000x

Design decision — sidecar over column-add (per 15000x L1)

Option	Pros	Cons
A — extend iu_collection_template_registry with template_family/version_seq/previous_collection_id	Single-table query for versioning	Forces NULL for the 2 existing 15000x rows; leaks versioning concerns into the "is_template" marker; harder rollback when rows exist
B — new sidecar iu_collection_template_version	Zero blast radius on 031; clean FK chain mig 031 → mig 032; per-table rollback boundary	Two-table query — mitigated by views

Decision: B (sidecar). Migration 032.

Validation

After migration 032: runtime/110 D9 PASS at 174 (28+28+63+6+12+21+16). D8_unregistered = 0 rows. R280 PASS at 24 catalog rows, all_resolvable = t.