Fix yang validation failure when table contains empty value

src/sonic-yang-mgmt/sonic_yang_ext.py

@@ -591,18 +591,23 @@ def _xlateListInContainer(self, model, yang, configC, table, exceptionList):
     """
     def _xlateContainerInContainer(self, model, yang, configC, table):
         ccontainer = model
-        #print(ccontainer['@name'])
-        yang[ccontainer['@name']] = dict()
-        if not configC.get(ccontainer['@name']):
+        ccName = ccontainer['@name']
+        yang[ccName] = dict()
+        if ccName not in configC:
+            # Inner container doesn't exist in config
             return
-        self.sysLog(msg="xlateProcessListOfContainer: {}".format(ccontainer['@name']))
-        self._xlateContainer(ccontainer, yang[ccontainer['@name']], \
-        configC[ccontainer['@name']], table)
+        if len(configC[ccName]) == 0:
+            # Empty container, clean config and return
+            del configC[ccName]
+            return
+        self.sysLog(msg="xlateProcessListOfContainer: {}".format(ccName))
+        self._xlateContainer(ccontainer, yang[ccName], \
+        configC[ccName], table)
         # clean empty container
-        if len(yang[ccontainer['@name']]) == 0:
-            del yang[ccontainer['@name']]
+        if len(yang[ccName]) == 0:
+            del yang[ccName]
         # remove copy after processing
-        del configC[ccontainer['@name']]
+        del configC[ccName]
 
         return
 

src/sonic-yang-models/tests/files/sample_config_db.json

@@ -304,7 +304,7 @@
                 "switch_id": "2",
                 "switch_type": "voq",
                 "max_cores": "8",
-                "sub_role": "FrondEnd",
+                "sub_role": "FrontEnd",
                 "dhcp_server": "disabled"
             }
         },

src/sonic-yang-models/tests/yang_model_tests/tests/tacacs.json

@@ -4,18 +4,21 @@
     },
     "TACPLUS_INVALID_TIMEOUT_TEST": {
         "desc": "Tacplus global configuration with invalid timeout value in TACPLUS table.",
-	"eStr": "TACACS timeout must be 1..60"
+        "eStr": "TACACS timeout must be 1..60"
     },
     "TACPLUS_NOT_PRESENT_SRC_INTF_TEST": {
         "desc": "Tacplus global configuration with a non existent port in TACPLUS table.",
         "eStrKey": "InvalidValue"
     },
+    "TACPLUS_VERIFY_VALID_EMPTY_GLOBAL": {
+        "desc": "Tacplus valid empty global configuration in TACPLUS table."
+    },
     "TACPLUS_SERVER_TEST" : {
         "desc": "Tacplus server configuration in TACPLUS_SERVER table."
     },
     "TACPLUS_SERVER_INVALID_PRIORITY_TEST": {
         "desc": "Tacplus server configuration with invalid priority value in TACPLUS_SERVER table.",
-	"eStr": "TACACS server priority must be 1..64"
+        "eStr": "TACACS server priority must be 1..64"
     },
     "TACPLUS_SERVER_INVALID_TIMEOUT_TEST" : {
         "desc": "Tacplus server configuration with invalid timeout value in TACPLUS_SERVER table.",

src/sonic-yang-models/tests/yang_model_tests/tests_config/tacacs.json

@@ -52,6 +52,16 @@
         }
     },
 
+    "TACPLUS_VERIFY_VALID_EMPTY_GLOBAL": {
+        "sonic-system-tacacs:sonic-system-tacacs": {
+            "sonic-system-tacacs:TACPLUS": {
+                "global": {
+                }
+            }
+        }
+
+    },
+
     "TACPLUS_SERVER_TEST": {
         "sonic-system-tacacs:sonic-system-tacacs": {
             "sonic-system-tacacs:TACPLUS_SERVER": {

src/sonic-yang-models/yang-models/sonic-device_metadata.yang

@@ -129,7 +129,7 @@ module sonic-device_metadata {
 
                 leaf sub_role {
                     type string;
-                    description "sub_role indicates if ASIC is FrondEnd or BackEnd.";
+                    description "sub_role indicates if ASIC is FrontEnd or BackEnd.";
                 }
 
                 leaf downstream_subrole {