fix(vector_stores/opensearch): translate the '*' wildcard to an exists query for every key (#6522)

tests/vector_stores/test_opensearch.py

@@ -643,13 +643,49 @@ class TestOpenSearchCustomFilters(TestOpenSearchFilterValidation):
         clauses = self._search_body()["query"]["bool"]["filter"]
         self.assertEqual(clauses, [{"term": {"payload.user_id.keyword": "alice"}}])
 
-    def test_search_ignores_wildcard_filter_value(self):
+    def test_search_translates_wildcard_filter_value_to_exists(self):
         self.os_db.search(query="", vectors=[[0.1] * 1536], filters={"user_id": "alice", "category": "*"})
         clauses = self._search_body()["query"]["bool"]["filter"]
-        self.assertEqual(clauses, [{"term": {"payload.user_id.keyword": "alice"}}])
+        self.assertEqual(
+            clauses,
+            [
+                {"term": {"payload.user_id.keyword": "alice"}},
+                {"exists": {"field": "payload.category"}},
+            ],
+        )
 
     def test_list_ignores_or_operator_filter(self):
         self.os_db.list(filters={"user_id": "alice", "$or": [{"a": 1}]})
         self.client_mock.search.assert_called_once()
         clauses = self._search_body()["query"]["bool"]["filter"]
         self.assertEqual(clauses, [{"term": {"payload.user_id.keyword": "alice"}}])
+
+
+class TestOpenSearchWildcardFilters(TestOpenSearchFilterValidation):
+    """The "*" wildcard means "any value" (a documented Platform pattern) and
+    must build an exists query — as opensearch.ts does — for every key,
+    including the identity keys, instead of a literal term match on "*"."""
+
+    def setUp(self):
+        super().setUp()
+        self.client_mock.search.return_value = {"hits": {"hits": []}}
+
+    def _search_body(self):
+        return self.client_mock.search.call_args[1]["body"]
+
+    def test_identity_key_wildcard_builds_exists_query(self):
+        self.os_db.search(query="", vectors=[[0.1] * 1536], filters={"agent_id": "*"})
+        clauses = self._search_body()["query"]["bool"]["filter"]
+        self.assertIn({"exists": {"field": "payload.agent_id"}}, clauses)
+        self.assertNotIn({"term": {"payload.agent_id.keyword": "*"}}, clauses)
+
+    def test_custom_key_wildcard_builds_exists_query(self):
+        self.os_db.list(filters={"category": "*"})
+        clauses = self._search_body()["query"]["bool"]["filter"]
+        self.assertIn({"exists": {"field": "payload.category"}}, clauses)
+
+    def test_wildcard_combines_with_term_filters(self):
+        self.os_db.keyword_search(query="q", filters={"user_id": "u1", "topic": "*"})
+        clauses = self._search_body()["query"]["bool"]["filter"]
+        self.assertIn({"term": {"payload.user_id.keyword": "u1"}}, clauses)
+        self.assertIn({"exists": {"field": "payload.topic"}}, clauses)