BE-1: Alembic migration to drop unique constraint for multiple connectors of same type per search space (idempotent)

surfsense_backend/alembic/versions/57_allow_multiple_connectors_per_type.py

@@ -0,0 +1,53 @@
+"""Allow multiple connectors of same type per search space
+
+Revision ID: 57
+Revises: 56
+Create Date: 2026-01-06 12:00:00.000000
+
+"""
+
+from collections.abc import Sequence
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision: str = "57"
+down_revision: str | None = "56"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+from sqlalchemy import text
+
+def upgrade() -> None:
+    connection = op.get_bind()
+    constraint_exists = connection.execute(
+        text("""
+            SELECT 1 FROM information_schema.table_constraints 
+            WHERE table_name='search_source_connectors' 
+              AND constraint_type='UNIQUE' 
+              AND constraint_name='uq_searchspace_user_connector_type'
+        """)
+    ).scalar()
+    if constraint_exists:
+        op.drop_constraint(
+            "uq_searchspace_user_connector_type",
+            "search_source_connectors",
+            type_="unique"
+        )
+
+def downgrade() -> None:
+    connection = op.get_bind()
+    constraint_exists = connection.execute(
+        text("""
+            SELECT 1 FROM information_schema.table_constraints 
+            WHERE table_name='search_source_connectors' 
+              AND constraint_type='UNIQUE' 
+              AND constraint_name='uq_searchspace_user_connector_type'
+        """)
+    ).scalar()
+    if not constraint_exists:
+        op.create_unique_constraint(
+            "uq_searchspace_user_connector_type",
+            "search_source_connectors",
+            ["search_space_id", "user_id", "connector_type"]
+        )
+