feat(identifiers): add reversible projection migration

Assistant: codex
Assistant-Model: gpt-5.6-sol
Assistant-Session: 01a023c0-a0a3-7c03-b395-5a0d2757214d

migrations/versions/b8d4f0a2c6e1_work_record_identifier_aliases.py

@@ -0,0 +1,182 @@
+"""add reversible work-record identifier migration support
+
+Revision ID: b8d4f0a2c6e1
+Revises: a7c3e9f1b4d2
+Create Date: 2026-08-22
+
+"""
+import sqlalchemy as sa
+from alembic import op
+from sqlalchemy.dialects.postgresql import UUID
+
+revision = "b8d4f0a2c6e1"
+down_revision = "a7c3e9f1b4d2"
+branch_labels = None
+depends_on = None
+
+
+_CASCADE_REFERENCES = """
+DO $$
+DECLARE
+    fk RECORD;
+    updated_definition TEXT;
+BEGIN
+    FOR fk IN
+        SELECT
+            constraint_row.conrelid::regclass AS relation_name,
+            constraint_row.conname AS constraint_name,
+            pg_get_constraintdef(constraint_row.oid) AS definition
+        FROM pg_constraint AS constraint_row
+        WHERE constraint_row.contype = 'f'
+          AND constraint_row.confrelid IN (
+              'workplans'::regclass,
+              'tasks'::regclass
+          )
+    LOOP
+        updated_definition := regexp_replace(
+            fk.definition,
+            ' ON UPDATE (NO ACTION|RESTRICT|CASCADE|SET NULL|SET DEFAULT)',
+            '',
+            'i'
+        );
+        IF position(' ON DELETE ' IN updated_definition) > 0 THEN
+            updated_definition := regexp_replace(
+                updated_definition,
+                ' ON DELETE ',
+                ' ON UPDATE CASCADE ON DELETE ',
+                'i'
+            );
+        ELSE
+            updated_definition := updated_definition || ' ON UPDATE CASCADE';
+        END IF;
+
+        EXECUTE format(
+            'ALTER TABLE %s DROP CONSTRAINT %I',
+            fk.relation_name,
+            fk.constraint_name
+        );
+        EXECUTE format(
+            'ALTER TABLE %s ADD CONSTRAINT %I %s',
+            fk.relation_name,
+            fk.constraint_name,
+            updated_definition
+        );
+    END LOOP;
+END $$;
+"""
+
+_REMOVE_UPDATE_CASCADE = """
+DO $$
+DECLARE
+    fk RECORD;
+    updated_definition TEXT;
+BEGIN
+    FOR fk IN
+        SELECT
+            constraint_row.conrelid::regclass AS relation_name,
+            constraint_row.conname AS constraint_name,
+            pg_get_constraintdef(constraint_row.oid) AS definition
+        FROM pg_constraint AS constraint_row
+        WHERE constraint_row.contype = 'f'
+          AND constraint_row.confrelid IN (
+              'workplans'::regclass,
+              'tasks'::regclass
+          )
+    LOOP
+        updated_definition := regexp_replace(
+            fk.definition,
+            ' ON UPDATE CASCADE',
+            '',
+            'i'
+        );
+        EXECUTE format(
+            'ALTER TABLE %s DROP CONSTRAINT %I',
+            fk.relation_name,
+            fk.constraint_name
+        );
+        EXECUTE format(
+            'ALTER TABLE %s ADD CONSTRAINT %I %s',
+            fk.relation_name,
+            fk.constraint_name,
+            updated_definition
+        );
+    END LOOP;
+END $$;
+"""
+
+
+def upgrade() -> None:
+    op.create_table(
+        "work_record_identifier_aliases",
+        sa.Column("id", UUID(as_uuid=True), primary_key=True),
+        sa.Column("old_id", UUID(as_uuid=True), nullable=False),
+        sa.Column("new_id", UUID(as_uuid=True), nullable=False),
+        sa.Column("record_kind", sa.String(length=20), nullable=False),
+        sa.Column("record_id", sa.String(length=160), nullable=False),
+        sa.Column("repo_slug", sa.String(length=100), nullable=False),
+        sa.Column("namespace", sa.String(length=64), nullable=False),
+        sa.Column("plan_sha256", sa.String(length=64), nullable=False),
+        sa.Column(
+            "migration_status",
+            sa.String(length=20),
+            nullable=False,
+            server_default="prepared",
+        ),
+        sa.Column("applied_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("reversed_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column(
+            "created_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.text("now()"),
+            nullable=False,
+        ),
+        sa.Column(
+            "updated_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.text("now()"),
+            nullable=False,
+        ),
+        sa.CheckConstraint(
+            "record_kind IN ('workplan', 'task')",
+            name="ck_work_record_identifier_aliases_kind",
+        ),
+        sa.CheckConstraint(
+            "migration_status IN ('prepared', 'applied', 'reversed')",
+            name="ck_work_record_identifier_aliases_status",
+        ),
+        sa.UniqueConstraint("old_id", name="uq_work_record_identifier_aliases_old_id"),
+        sa.UniqueConstraint("new_id", name="uq_work_record_identifier_aliases_new_id"),
+    )
+    op.create_index(
+        "ix_work_record_identifier_aliases_record_id",
+        "work_record_identifier_aliases",
+        ["record_id"],
+    )
+    op.create_index(
+        "ix_work_record_identifier_aliases_repo_slug",
+        "work_record_identifier_aliases",
+        ["repo_slug"],
+    )
+    op.create_index(
+        "ix_work_record_identifier_aliases_plan_sha256",
+        "work_record_identifier_aliases",
+        ["plan_sha256"],
+    )
+    op.execute(_CASCADE_REFERENCES)
+
+
+def downgrade() -> None:
+    op.execute(_REMOVE_UPDATE_CASCADE)
+    op.drop_index(
+        "ix_work_record_identifier_aliases_plan_sha256",
+        table_name="work_record_identifier_aliases",
+    )
+    op.drop_index(
+        "ix_work_record_identifier_aliases_repo_slug",
+        table_name="work_record_identifier_aliases",
+    )
+    op.drop_index(
+        "ix_work_record_identifier_aliases_record_id",
+        table_name="work_record_identifier_aliases",
+    )
+    op.drop_table("work_record_identifier_aliases")