[SPARK-29833][YARN] Add FileNotFoundException check for spark.yarn.jars

### What changes were proposed in this pull request?

When set `spark.yarn.jars=/xxx/xxx` which is just a no schema path, spark will throw a NullPointerException.

The reason is hdfs will return null if pathFs.globStatus(path) is not exist, and spark just use `pathFs.globStatus(path).filter(_.isFile())` without check it.

### Why are the changes needed?

Avoid NullPointerException.

### Does this PR introduce any user-facing change?

Yes. User will get a FileNotFoundException instead NullPointerException when `spark.yarn.jars` does not have schema and not exists.

### How was this patch tested?

Add UT.

Closes apache#26462 from ulysses-you/check-yarn-jars-path-exist.

Authored-by: ulysses <[email protected]>
Signed-off-by: Marcelo Vanzin <[email protected]>

Author: ulysses-you

resource-managers/yarn/src/main/scala/org/apache/spark/deploy/yarn/Client.scala

@@ -538,7 +538,11 @@ private[spark] class Client(
             if (!Utils.isLocalUri(jar)) {
               val path = getQualifiedLocalPath(Utils.resolveURI(jar), hadoopConf)
               val pathFs = FileSystem.get(path.toUri(), hadoopConf)
-              pathFs.globStatus(path).filter(_.isFile()).foreach { entry =>
+              val fss = pathFs.globStatus(path)
+              if (fss == null) {
+                throw new FileNotFoundException(s"Path ${path.toString} does not exist")
+              }
+              fss.filter(_.isFile()).foreach { entry =>
                 val uri = entry.getPath().toUri()
                 statCache.update(uri, entry)
                 distribute(uri.toString(), targetDir = Some(LOCALIZED_LIB_DIR))

resource-managers/yarn/src/test/scala/org/apache/spark/deploy/yarn/ClientSuite.scala

@@ -17,7 +17,7 @@
 
 package org.apache.spark.deploy.yarn
 
-import java.io.{File, FileInputStream, FileOutputStream}
+import java.io.{File, FileInputStream, FileNotFoundException, FileOutputStream}
 import java.net.URI
 import java.util.Properties
 
@@ -473,6 +473,18 @@ class ClientSuite extends SparkFunSuite with Matchers {
     assert(allResourceInfo.get(yarnMadeupResource).get === 5)
   }
 
+  test("test yarn jars path not exists") {
+    withTempDir { dir =>
+      val conf = new SparkConf().set(SPARK_JARS, Seq(dir.getAbsolutePath + "/test"))
+      val client = new Client(new ClientArguments(Array()), conf, null)
+      withTempDir { distDir =>
+        intercept[FileNotFoundException] {
+          client.prepareLocalResources(new Path(distDir.getAbsolutePath), Nil)
+        }
+      }
+    }
+  }
+
   private val matching = Seq(
     ("files URI match test1", "file:///file1", "file:///file2"),
     ("files URI match test2", "file:///c:file1", "file://c:file2"),