[SPARK-12708][UI] Sorting task error in Stages Page when yarn mode.

If sort column contains slash(e.g. "Executor ID / Host") when yarn mode,sort fail with following message.

![spark-12708](https://cloud.githubusercontent.com/assets/6679275/12193320/80814f8c-b62a-11e5-9914-7bf3907029df.png)

Ｉt's similar to SPARK-4313 .

Author: root <root@R520T1.(none)>
Author: Koyo Yoshida <koyo0615@gmail.com>

Closes #10663 from yoshidakuy/SPARK-12708.

1 files changed, 14 insertions, 0 deletions

diff --git a/core/src/test/scala/org/apache/spark/ui/UIUtilsSuite.scala b/core/src/test/scala/org/apache/spark/ui/UIUtilsSuite.scala
index dd8d5ec27f..bc8a5d494d 100644
--- a/core/src/test/scala/org/apache/spark/ui/UIUtilsSuite.scala
+++ b/core/src/test/scala/org/apache/spark/ui/UIUtilsSuite.scala
@@ -67,6 +67,20 @@ class UIUtilsSuite extends SparkFunSuite {
       s"\nRunning progress bar should round down\n\nExpected:\n$expected\nGenerated:\n$generated")
   }
 
+  test("decodeURLParameter (SPARK-12708: Sorting task error in Stages Page when yarn mode.)") {
+    val encoded1 = "%252F"
+    val decoded1 = "/"
+    val encoded2 = "%253Cdriver%253E"
+    val decoded2 = "<driver>"
+
+    assert(decoded1 === decodeURLParameter(encoded1))
+    assert(decoded2 === decodeURLParameter(encoded2))
+
+    // verify that no affect to decoded URL.
+    assert(decoded1 === decodeURLParameter(decoded1))
+    assert(decoded2 === decodeURLParameter(decoded2))
+  }
+
   private def verify(
       desc: String, expected: Elem, errorMsg: String = "", baseUrl: String = ""): Unit = {
     val generated = makeDescription(desc, baseUrl)