address andrew's comments

Author: lw-lin

core/src/main/scala/org/apache/spark/ui/UIUtils.scala

@@ -416,6 +416,14 @@ private[spark] object UIUtils extends Logging {
    * Note: In terms of security, only anchor tags with root relative links are supported. So any
    * attempts to embed links outside Spark UI, or other tags like <script> will cause in the whole
    * description to be treated as plain text.
+   *
+   * @param desc        the original job or stage description string, which may contain html tags.
+   * @param basePathUri with which to prepend the relative links; this is used when plainText is
+   *                    false.
+   * @param plainText   whether to keep only plain text (i.e. remove html tags) from the original
+   *                    description string.
+   * @return the HTML rendering of the job or stage description, which will be a Text when plainText
+   *         is true, and an Elem otherwise.
    */
   def makeDescription(desc: String, basePathUri: String, plainText: Boolean = false): NodeSeq = {
     import scala.language.postfixOps
@@ -445,32 +453,33 @@ private[spark] object UIUtils extends Logging {
           "Links in job descriptions must be root-relative:\n" + allLinks.mkString("\n\t"))
       }
 
-      val rule = if (plainText) {
-        // Remove all tags, retaining only their texts
-        new RewriteRule() {
-          override def transform(n: Node): Seq[Node] = {
-            n match {
-              case e: Elem if e.child isEmpty => Text(e.text)
-              case e: Elem if e.child nonEmpty => Text(e.child.flatMap(transform).text)
-              case _ => n
+      val rule =
+        if (plainText) {
+          // Remove all tags, retaining only their texts
+          new RewriteRule() {
+            override def transform(n: Node): Seq[Node] = {
+              n match {
+                case e: Elem if e.child isEmpty => Text(e.text)
+                case e: Elem if e.child nonEmpty => Text(e.child.flatMap(transform).text)
+                case _ => n
+              }
             }
           }
         }
-      }
-      else {
-        // Prepend the relative links with basePathUri
-        new RewriteRule() {
-          override def transform(n: Node): Seq[Node] = {
-            n match {
-              case e: Elem if e \ "@href" nonEmpty =>
-                val relativePath = e.attribute("href").get.toString
-                val fullUri = s"${basePathUri.stripSuffix("/")}/${relativePath.stripPrefix("/")}"
-                e % Attribute(null, "href", fullUri, Null)
-              case _ => n
+        else {
+          // Prepend the relative links with basePathUri
+          new RewriteRule() {
+            override def transform(n: Node): Seq[Node] = {
+              n match {
+                case e: Elem if e \ "@href" nonEmpty =>
+                  val relativePath = e.attribute("href").get.toString
+                  val fullUri = s"${basePathUri.stripSuffix("/")}/${relativePath.stripPrefix("/")}"
+                  e % Attribute(null, "href", fullUri, Null)
+                case _ => n
+              }
             }
           }
         }
-      }
       new RuleTransformer(rule).transform(xml)
     } catch {
       case NonFatal(e) =>

core/src/main/scala/org/apache/spark/ui/jobs/AllJobsPage.scala

@@ -71,11 +71,12 @@ private[ui] class AllJobsPage(parent: JobsTab) extends WebUIPage("") {
       val jobId = jobUIData.jobId
       val status = jobUIData.status
       val (jobName, jobDescription) = getLastStageNameAndDescription(jobUIData)
-      val displayJobDescription = if (jobDescription.isEmpty) {
-        jobName
-      } else {
-        UIUtils.makeDescription(jobDescription, "", plainText = true).text
-      }
+      val displayJobDescription =
+        if (jobDescription.isEmpty) {
+          jobName
+        } else {
+          UIUtils.makeDescription(jobDescription, "", plainText = true).text
+        }
       val submissionTime = jobUIData.submissionTime.get
       val completionTimeOpt = jobUIData.completionTime
       val completionTime = completionTimeOpt.getOrElse(System.currentTimeMillis())