Fix exception when force delete namespace (apache#9691)

When force delete namespace, the partition topics to be deleted are list twice and a exception will happen when delete the topic second time.
![deletens](https://user-images.githubusercontent.com/65590138/108942063-3e26d580-7691-11eb-82f9-43c5f7217a08.png)

pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/impl/NamespacesBase.java

@@ -377,9 +377,7 @@ protected void internalDeleteNamespaceForcefully(AsyncResponse asyncResponse, bo
 
         List<String> topics;
         try {
-            topics = pulsar().getNamespaceService().getListOfPersistentTopics(namespaceName).join();
-            topics.addAll(getPartitionedTopicList(TopicDomain.persistent));
-            topics.addAll(getPartitionedTopicList(TopicDomain.non_persistent));
+            topics = pulsar().getNamespaceService().getFullListOfTopics(namespaceName).join();
         } catch (Exception e) {
             asyncResponse.resume(new RestException(e));
             return;

pulsar-broker/src/test/java/org/apache/pulsar/broker/admin/NamespacesTest.java

@@ -19,10 +19,6 @@
 package org.apache.pulsar.broker.admin;
 
 import static org.apache.pulsar.broker.cache.ConfigurationCacheService.POLICIES;
-
-import org.apache.pulsar.broker.BrokerTestUtil;
-import org.apache.pulsar.client.api.ConsumerBuilder;
-import org.apache.pulsar.client.api.PulsarClientException;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.doNothing;
 import static org.mockito.Mockito.doReturn;
@@ -43,7 +39,6 @@
 import java.lang.reflect.Field;
 import java.net.URI;
 import java.net.URL;
-import java.nio.charset.StandardCharsets;
 import java.util.EnumSet;
 import java.util.HashSet;
 import java.util.List;
@@ -65,6 +60,7 @@
 import org.apache.bookkeeper.mledger.LedgerOffloader;
 import org.apache.bookkeeper.mledger.ManagedLedgerConfig;
 import org.apache.bookkeeper.util.ZkUtils;
+import org.apache.pulsar.broker.BrokerTestUtil;
 import org.apache.pulsar.broker.admin.v1.Namespaces;
 import org.apache.pulsar.broker.admin.v1.PersistentTopics;
 import org.apache.pulsar.broker.auth.MockedPulsarServiceBaseTest;
@@ -77,8 +73,9 @@
 import org.apache.pulsar.client.admin.PulsarAdminException;
 import org.apache.pulsar.client.admin.PulsarAdminException.NotFoundException;
 import org.apache.pulsar.client.api.Consumer;
+import org.apache.pulsar.client.api.ConsumerBuilder;
 import org.apache.pulsar.client.api.Producer;
-import org.apache.pulsar.client.api.Schema;
+import org.apache.pulsar.client.api.PulsarClientException;
 import org.apache.pulsar.client.api.SubscriptionType;
 import org.apache.pulsar.common.naming.NamespaceBundle;
 import org.apache.pulsar.common.naming.NamespaceBundles;
@@ -95,7 +92,6 @@
 import org.apache.pulsar.common.policies.data.RetentionPolicies;
 import org.apache.pulsar.common.policies.data.SubscribeRate;
 import org.apache.pulsar.common.policies.data.TenantInfo;
-import org.apache.pulsar.common.policies.data.TopicPolicies;
 import org.apache.pulsar.common.util.ObjectMapperFactory;
 import org.apache.pulsar.metadata.cache.impl.MetadataCacheImpl;
 import org.apache.pulsar.metadata.impl.AbstractMetadataStore;
@@ -1143,11 +1139,14 @@ public void testDeleteNamespace() throws Exception {
     public void testForceDeleteNamespace() throws Exception {
         String namespace = BrokerTestUtil.newUniqueName(this.testTenant + "/namespace");
         String topic = namespace + "/topic";
+        String non_persistent_topic = "non-persistent://" + topic;
 
         admin.namespaces().createNamespace(namespace, 100);
 
         admin.topics().createPartitionedTopic(topic, 10);
 
+        admin.topics().createNonPartitionedTopic(non_persistent_topic);
+
         List<String> topicList = admin.topics().getList(namespace);
         assertFalse(topicList.isEmpty());