Add Postbox message authoring and concurrency

src/govoplan_postbox/backend/migrations/versions/f5c8d0e3b7a2_v012_authoring_and_occ.py

@@ -0,0 +1,65 @@
+"""v0.1.2 message authoring and optimistic concurrency
+
+Revision ID: f5c8d0e3b7a2
+Revises: e4b7c9d2a6f1
+Create Date: 2026-07-31 16:30:00.000000
+"""
+from __future__ import annotations
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = "f5c8d0e3b7a2"
+down_revision = "e4b7c9d2a6f1"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    for table_name in (
+        "postbox_templates",
+        "postboxes",
+        "postbox_groupings",
+    ):
+        with op.batch_alter_table(table_name) as batch_op:
+            batch_op.add_column(
+                sa.Column(
+                    "resource_revision",
+                    sa.Integer(),
+                    nullable=False,
+                    server_default=sa.text("1"),
+                )
+            )
+
+    with op.batch_alter_table("postbox_messages") as batch_op:
+        batch_op.add_column(
+            sa.Column("authoring_key", sa.String(length=255), nullable=True)
+        )
+        batch_op.create_index(
+            "ix_postbox_messages_authoring_key",
+            ("authoring_key",),
+            unique=False,
+        )
+        batch_op.create_unique_constraint(
+            "uq_postbox_messages_authoring_key",
+            ("tenant_id", "postbox_id", "authoring_key"),
+        )
+
+
+def downgrade() -> None:
+    with op.batch_alter_table("postbox_messages") as batch_op:
+        batch_op.drop_constraint(
+            "uq_postbox_messages_authoring_key",
+            type_="unique",
+        )
+        batch_op.drop_index("ix_postbox_messages_authoring_key")
+        batch_op.drop_column("authoring_key")
+
+    for table_name in (
+        "postbox_groupings",
+        "postboxes",
+        "postbox_templates",
+    ):
+        with op.batch_alter_table(table_name) as batch_op:
+            batch_op.drop_column("resource_revision")