[SPARK-28670][SQL] create function should thrown Exception if the resource is not found

## What changes were proposed in this pull request?

Create temporary or permanent function it should throw AnalysisException if the resource is not found. Need to keep behavior consistent across permanent and temporary functions.

## How was this patch tested?

Added UT and also tested manually

**Before Fix**
If the UDF resource is not present then on creation of temporary function it throws AnalysisException where as for permanent function it does not throw. Permanent funtcion  throws AnalysisException only after select operation is performed.

**After Fix**

For temporary and permanent function check for the resource, if the UDF resource is not found then throw AnalysisException

![rt](https://user-images.githubusercontent.com/35216143/62781519-d1131580-bad5-11e9-9d58-69e65be86c03.png)

Closes #25399 from sandeep-katta/funcIssue.

Authored-by: sandeep katta <sandeep.katta2007@gmail.com>
Signed-off-by: Takeshi Yamamuro <yamamuro@apache.org>

docs/sql-migration-guide.md

@@ -23,6 +23,8 @@ license: |
 {:toc}
 
 ## Upgrading from Spark SQL 2.4 to 3.0
+  - Since Spark 3.0, the permanent function created using resource throws `AnalysisException` if the resource does not exists.
+  
   - Since Spark 3.0, when inserting a value into a table column with a different data type, the type coercion is performed as per ANSI SQL standard. Certain unreasonable type conversions such as converting `string` to `int` and `double` to `boolean` are disallowed. A runtime exception will be thrown if the value is out-of-range for the data type of the column. In Spark version 2.4 and earlier, type conversions during table insertion are allowed as long as they are valid `Cast`. When inserting an out-of-range value to a integral field, the low-order bits of the value is inserted(the same as Java/Scala numeric type casting). For example, if 257 is inserted to a field of byte type, the result is 1. The behavior is controlled by the option `spark.sql.storeAssignmentPolicy`, with a default value as "ANSI". Setting the option as "Legacy" restores the previous behavior.
 
   - In Spark 3.0, the deprecated methods `SQLContext.createExternalTable` and `SparkSession.createExternalTable` have been removed in favor of its replacement, `createTable`.

sql/core/src/main/scala/org/apache/spark/sql/execution/command/functions.scala

@@ -19,11 +19,13 @@ package org.apache.spark.sql.execution.command
 
 import java.util.Locale
 
+import org.apache.hadoop.fs.Path
+
 import org.apache.spark.sql.{AnalysisException, Row, SparkSession}
 import org.apache.spark.sql.catalyst.FunctionIdentifier
 import org.apache.spark.sql.catalyst.analysis.{FunctionRegistry, NoSuchFunctionException}
 import org.apache.spark.sql.catalyst.catalog.{CatalogFunction, FunctionResource}
-import org.apache.spark.sql.catalyst.expressions.{Attribute, ExpressionInfo}
+import org.apache.spark.sql.catalyst.expressions.Attribute
 import org.apache.spark.sql.catalyst.util.StringUtils
 import org.apache.spark.sql.types.{StringType, StructField, StructType}
 
@@ -74,6 +76,15 @@ case class CreateFunctionCommand(
   }
 
   override def run(sparkSession: SparkSession): Seq[Row] = {
+    // Checks if the given resources exist
+    val hadoopConf = sparkSession.sparkContext.hadoopConfiguration
+    val nonExistentResources = resources.filter { r =>
+      val path = new Path(r.uri)
+      !path.getFileSystem(hadoopConf).exists(path)
+    }
+    if (nonExistentResources.nonEmpty) {
+      throw new AnalysisException(s"Resources not found: ${nonExistentResources.mkString(",")}")
+    }
     val catalog = sparkSession.sessionState.catalog
     val func = CatalogFunction(FunctionIdentifier(functionName, databaseName), className, resources)
     if (isTemp) {

sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala

@@ -3370,6 +3370,20 @@ class SQLQuerySuite extends QueryTest with SharedSparkSession {
       checkAnswer(df5, Array.empty[Row])
     }
   }
+
+  test("SPARK-28670: create function should throw AnalysisException if UDF class not found") {
+    Seq(true, false).foreach { isTemporary =>
+      val exp = intercept[AnalysisException] {
+        sql(
+          s"""
+             |CREATE ${if (isTemporary) "TEMPORARY" else ""} FUNCTION udtf_test
+             |AS 'org.apache.spark.sql.hive.execution.UDFTest'
+             |USING JAR '/var/invalid/invalid.jar'
+        """.stripMargin)
+      }
+      assert(exp.getMessage.contains("Resources not found"))
+    }
+  }
 }
 
 case class Foo(bar: Option[String])