commit 30/9

migrations/005_mne_compatibility_guards.sql

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+-- Corrective migration: preserve the already applied 001-004 files.
+BEGIN;
+SET LOCAL lock_timeout = '10s';
+SELECT pg_advisory_xact_lock(hashtextextended('mne:005_compatibility_guards',0));
+DO $guard$
+BEGIN
+ IF to_regclass('mne.compatibility_controls') IS NULL THEN
+  RAISE EXCEPTION '004 compatibility migration is required';
+ END IF;
+ IF EXISTS(SELECT 1 FROM mne.compatibility_controls WHERE capability='canonical_read' AND (enabled OR percentage<>0)) THEN
+  RAISE EXCEPTION 'Canonical control is not disabled; explicit reconciliation required';
+ END IF;
+ IF EXISTS(SELECT 1 FROM pg_constraint WHERE conrelid='mne.compatibility_controls'::regclass AND conname='ck_mne_005_canonical_disabled') THEN
+  IF (SELECT pg_get_constraintdef(oid) FROM pg_constraint WHERE conrelid='mne.compatibility_controls'::regclass AND conname='ck_mne_005_canonical_disabled')
+   <> $$CHECK (((capability <> 'canonical_read'::text) OR ((NOT enabled) AND (percentage = 0))))$$ THEN
+   RAISE EXCEPTION 'Unexpected canonical control constraint';
+  END IF;
+ ELSE
+  ALTER TABLE mne.compatibility_controls ADD CONSTRAINT ck_mne_005_canonical_disabled
+   CHECK (capability <> 'canonical_read' OR (NOT enabled AND percentage=0));
+ END IF;
+END $guard$;
+COMMIT;