[SPARK-16935][SQL] Verification of Function-related ExternalCatalog APIs

### What changes were proposed in this pull request?
Function-related `HiveExternalCatalog` APIs do not have enough verification logics. After the PR, `HiveExternalCatalog` and `InMemoryCatalog` become consistent in the error handling.

For example, below is the exception we got when calling `renameFunction`.
```
15:13:40.369 WARN org.apache.hadoop.hive.metastore.ObjectStore: Failed to get database db1, returning NoSuchObjectException
15:13:40.377 WARN org.apache.hadoop.hive.metastore.ObjectStore: Failed to get database db2, returning NoSuchObjectException
15:13:40.739 ERROR DataNucleus.Datastore.Persist: Update of object "org.apache.hadoop.hive.metastore.model.MFunction205629e9" using statement "UPDATE FUNCS SET FUNC_NAME=? WHERE FUNC_ID=?" failed : org.apache.derby.shared.common.error.DerbySQLIntegrityConstraintViolationException: The statement was aborted because it would have caused a duplicate key value in a unique or primary key constraint or unique index identified by 'UNIQUEFUNCTION' defined on 'FUNCS'.
	at org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException(Unknown Source)
	at org.apache.derby.impl.jdbc.Util.generateCsSQLException(Unknown Source)
	at org.apache.derby.impl.jdbc.TransactionResourceImpl.wrapInSQLException(Unknown Source)
	at org.apache.derby.impl.jdbc.TransactionResourceImpl.handleException(Unknown Source)
```

### How was this patch tested?
Improved the existing test cases to check whether the messages are right.

Author: gatorsmile <gatorsmile@gmail.com>

Closes #14521 from gatorsmile/functionChecking.

1 files changed, 8 insertions, 0 deletions

diff --git a/sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveExternalCatalog.scala b/sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveExternalCatalog.scala
index ed87ac3c3e..8541ae2322 100644
--- a/sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveExternalCatalog.scala
+++ b/sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveExternalCatalog.scala
@@ -570,31 +570,39 @@ private[spark] class HiveExternalCatalog(conf: SparkConf, hadoopConf: Configurat
   override def createFunction(
       db: String,
       funcDefinition: CatalogFunction): Unit = withClient {
+    requireDbExists(db)
     // Hive's metastore is case insensitive. However, Hive's createFunction does
     // not normalize the function name (unlike the getFunction part). So,
     // we are normalizing the function name.
     val functionName = funcDefinition.identifier.funcName.toLowerCase
+    requireFunctionNotExists(db, functionName)
     val functionIdentifier = funcDefinition.identifier.copy(funcName = functionName)
     client.createFunction(db, funcDefinition.copy(identifier = functionIdentifier))
   }
 
   override def dropFunction(db: String, name: String): Unit = withClient {
+    requireFunctionExists(db, name)
     client.dropFunction(db, name)
   }
 
   override def renameFunction(db: String, oldName: String, newName: String): Unit = withClient {
+    requireFunctionExists(db, oldName)
+    requireFunctionNotExists(db, newName)
     client.renameFunction(db, oldName, newName)
   }
 
   override def getFunction(db: String, funcName: String): CatalogFunction = withClient {
+    requireFunctionExists(db, funcName)
     client.getFunction(db, funcName)
   }
 
   override def functionExists(db: String, funcName: String): Boolean = withClient {
+    requireDbExists(db)
     client.functionExists(db, funcName)
   }
 
   override def listFunctions(db: String, pattern: String): Seq[String] = withClient {
+    requireDbExists(db)
     client.listFunctions(db, pattern)
   }