fix: remove len(global_asset_ids)<=1 guard that silently emptied results for 2+ globalAssetId filters

Author: zrgt

server/app/interfaces/repository.py

@@ -463,10 +463,7 @@ def _get_shells(self, request: Request) -> Tuple[Iterator[model.AssetAdministrat
                             for specific_asset_id in specific_asset_ids
                         )
                     )
-                    and (
-                        len(global_asset_ids) <= 1
-                        and (not global_asset_ids or shell.asset_information.global_asset_id in global_asset_ids)
-                    )
+                    and (not global_asset_ids or shell.asset_information.global_asset_id in global_asset_ids)
                 ),
                 aas,
             )

server/test/interfaces/test_shells_asset_ids.py

@@ -0,0 +1,43 @@
+# Copyright (c) 2026 the Eclipse BaSyx Authors
+#
+# This program and the accompanying materials are made available under the terms of the MIT License, available in
+# the LICENSE file of this project.
+#
+# SPDX-License-Identifier: MIT
+
+import base64
+import json
+import unittest
+
+from basyx.aas import model
+from basyx.aas.adapter.aasx import DictSupplementaryFileContainer
+from basyx.aas.examples.data.example_aas import create_full_example
+from werkzeug.test import Client
+
+from app.interfaces.repository import WSGIApp
+
+BASE_PATH = "/api/v3.1"
+
+
+def _encode_asset_id(name: str, value: str) -> str:
+    payload = json.dumps({"name": name, "value": value})
+    return base64.urlsafe_b64encode(payload.encode()).decode()
+
+
+class ShellsAssetIdsTest(unittest.TestCase):
+    def setUp(self) -> None:
+        self.example_data = create_full_example()
+        app = WSGIApp(self.example_data, DictSupplementaryFileContainer())
+        self.client = Client(app)
+
+    def test_multiple_global_asset_ids_returns_matching_results(self) -> None:
+        aas_list = [obj for obj in self.example_data if isinstance(obj, model.AssetAdministrationShell)]
+        known_id = aas_list[0].asset_information.global_asset_id
+        unknown_id = "http://example.org/nonexistent_asset"
+        id1 = _encode_asset_id("globalAssetId", known_id)
+        id2 = _encode_asset_id("globalAssetId", unknown_id)
+        response = self.client.get(f"{BASE_PATH}/shells?assetIds={id1}&assetIds={id2}")
+        self.assertEqual(200, response.status_code)
+        result = json.loads(response.data)
+        returned_ids = [r["id"] for r in result]
+        self.assertIn(aas_list[0].id, returned_ids)