Merge pull request #7646 from menghaoranss/0928

Fixes NPE when create database by rdl & delete schema in config center when drop database

shardingsphere-governance/shardingsphere-governance-core/shardingsphere-governance-core-config/src/main/java/org/apache/shardingsphere/governance/core/config/ConfigCenter.java

@@ -249,7 +249,8 @@ public final class ConfigCenter {
     
     private void persistSchema(final String schemaName, final boolean isDrop) {
         String schemaNames = repository.get(node.getSchemasPath());
-        Collection<String> schemas = new LinkedHashSet<>(Splitter.on(",").splitToList(schemaNames));
+        Collection<String> schemas = Strings.isNullOrEmpty(schemaNames) ? new LinkedHashSet<>() 
+                : new LinkedHashSet<>(Splitter.on(",").splitToList(schemaNames));
         if (isDrop) {
             schemas.remove(schemaName);
         } else if (!schemas.contains(schemaName)) {
@@ -357,6 +358,15 @@ public final class ConfigCenter {
         return Optional.of(new RuleSchemaMetaDataYamlSwapper().swapToObject(YamlEngine.unmarshal(path, YamlRuleSchemaMetaData.class)));
     }
     
+    /**
+     * Delete schema.
+     * 
+     * @param schemaName schema name
+     */
+    public void deleteSchema(final String schemaName) {
+        repository.delete(node.getSchemaNamePath(schemaName));
+    }
+    
     private boolean hasAuthentication() {
         return !Strings.isNullOrEmpty(repository.get(node.getAuthenticationPath()));
     }

shardingsphere-governance/shardingsphere-governance-core/shardingsphere-governance-core-config/src/test/java/org/apache/shardingsphere/governance/core/config/ConfigCenterTest.java

@@ -533,4 +533,11 @@ public final class ConfigCenterTest {
         configCenter.renew(event);
         verify(configurationRepository).persist(eq("/schemas/sharding_db/table"), anyString());
     }
+    
+    @Test
+    public void assertDeleteSchema() {
+        ConfigCenter configCenter = new ConfigCenter(configurationRepository);
+        configCenter.deleteSchema("sharding_db");
+        verify(configurationRepository).delete(eq("/schemas/sharding_db"));
+    }
 }

shardingsphere-governance/shardingsphere-governance-core/shardingsphere-governance-core-context/src/main/java/org/apache/shardingsphere/governance/context/schema/GovernanceSchemaContexts.java

@@ -175,6 +175,7 @@ public final class GovernanceSchemaContexts implements SchemaContexts {
         Map<String, SchemaContext> schemas = new HashMap<>(schemaContexts.getSchemaContextMap());
         schemas.remove(event.getSchemaName());
         schemaContexts = new StandardSchemaContexts(schemas, schemaContexts.getAuthentication(), schemaContexts.getProps(), schemaContexts.getDatabaseType());
+        governanceFacade.getConfigCenter().deleteSchema(event.getSchemaName());
     }
     
     /**