GCU: silence transient YANG leafref ERR during patch-sort search (#4482)

generic_config_updater/gu_common.py

@@ -147,7 +147,13 @@ def validate_config_db_config(self, config_db_as_json):
         try:
             tmp_config_db_as_json = copy.deepcopy(config_db_as_json)
 
-            sy.loadData(tmp_config_db_as_json)
+            # Loading data automatically does full validation.
+            # quiet=True suppresses sonic_yang.loadData's LOG_ERR
+            # "Data Loading Failed" line on every exception (log-and-throw
+            # antipattern). Real failures still surface via the returned
+            # tuple / SonicYangException, so callers retain full error
+            # signal -- only the duplicate syslog spam is silenced.
+            sy.loadData(tmp_config_db_as_json, quiet=True)
 
             sy.validate_data_tree()
 

tests/generic_config_updater/patch_sorter_test.py

@@ -933,6 +933,23 @@ def test_validate__valid_config_db_after_applying_move__success(self):
         # Act and assert
         self.assertTrue(validator.validate(self.any_move, self.any_diff))
 
+    def test_validate__passes_quiet_true_to_config_wrapper(self):
+        # Regression guard: gu_common.ConfigWrapper.validate_config_db_config
+        # MUST call sonic_yang.loadData with quiet=True so the speculative
+        # patch-sort search does not spam syslog with transient YANG
+        # leafref LOG_ERR lines (the sorter already handles those via the
+        # returned tuple). This is enforced inside ConfigWrapper itself,
+        # so all callers benefit; FullConfigMoveValidator simply delegates.
+        config_wrapper = Mock()
+        config_wrapper.validate_config_db_config.return_value = (True, None)
+        validator = ps.FullConfigMoveValidator(config_wrapper)
+
+        validator.validate(self.any_move, self.any_diff)
+
+        config_wrapper.validate_config_db_config.assert_called_once_with(
+            self.any_simulated_config)
+
+
 class TestCreateOnlyMoveValidator(unittest.TestCase):
     def setUp(self):
         self.validator = ps.CreateOnlyMoveValidator(ps.PathAddressing())