Document issue

tests/integration/schema/updates/add/field/with_relation_test.go

@@ -0,0 +1,46 @@
+// Copyright 2024 Democratized Data Foundation
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+package field
+
+import (
+	"testing"
+
+	testUtils "github.com/sourcenetwork/defradb/tests/integration"
+)
+
+func TestSchemaUpdatesAddField_DoesNotAffectExistingRelation(t *testing.T) {
+	test := testUtils.TestCase{
+		Actions: []any{
+			testUtils.SchemaUpdate{
+				Schema: `
+					type Book {
+						name: String
+						author: Author
+					}
+
+					type Author {
+						name: String
+						books: [Book]
+					}
+				`,
+			},
+			testUtils.SchemaPatch{
+				Patch: `
+					[
+						{ "op": "add", "path": "/Book/Fields/-", "value": {"Name": "rating", "Kind": 4} }
+					]
+				`,
+				ExpectedError: "mutating an existing field is not supported.",
+			},
+		},
+	}
+	testUtils.ExecuteTestCase(t, test)
+}