[SPARK-1199][REPL] Remove VALId and use the original import style for defined classes.

This is an alternate solution to #1176.

Author: Prashant Sharma <prashant.s@imaginea.com>

Closes #1179 from ScrapCodes/SPARK-1199/repl-fix-second-approach and squashes the following commits:

820b34b [Prashant Sharma] Here we generate two kinds of import wrappers based on whether it is a class or not.

repl/src/main/scala/org/apache/spark/repl/SparkIMain.scala

@@ -744,7 +744,7 @@ import org.apache.spark.util.Utils
    *
    *  Read! Eval! Print! Some of that not yet centralized here.
    */
-  class ReadEvalPrint(lineId: Int) {
+  class ReadEvalPrint(val lineId: Int) {
     def this() = this(freshLineId())
 
     private var lastRun: Run = _
@@ -1241,7 +1241,10 @@ import org.apache.spark.util.Utils
     // old style
     beSilentDuring(parse(code)) foreach { ts =>
       ts foreach { t =>
-        withoutUnwrapping(logDebug(asCompactString(t)))
+        if (isShow || isShowRaw)
+          withoutUnwrapping(echo(asCompactString(t)))
+        else
+          withoutUnwrapping(logDebug(asCompactString(t)))
       }
     }
   }

repl/src/main/scala/org/apache/spark/repl/SparkImports.scala

@@ -182,15 +182,26 @@ trait SparkImports {
         // ambiguity errors will not be generated. Also, quote
         // the name of the variable, so that we don't need to
         // handle quoting keywords separately.
+        case x: ClassHandler =>
+        // I am trying to guess if the import is a defined class
+        // This is an ugly hack, I am not 100% sure of the consequences.
+        // Here we, let everything but "defined classes" use the import with val.
+        // The reason for this is, otherwise the remote executor tries to pull the
+        // classes involved and may fail.
+          for (imv <- x.definedNames) {
+            val objName = req.lineRep.readPath
+            code.append("import " + objName + ".INSTANCE" + req.accessPath + ".`" + imv + "`\n")
+          }
+
         case x =>
           for (imv <- x.definedNames) {
             if (currentImps contains imv) addWrapper()
             val objName = req.lineRep.readPath
-            val valName = "$VAL" + newValId();
+            val valName = "$VAL" + req.lineRep.lineId
 
             if(!code.toString.endsWith(".`" + imv + "`;\n")) { // Which means already imported
-               code.append("val " + valName + " = " + objName + ".INSTANCE;\n")
+                code.append("val " + valName + " = " + objName + ".INSTANCE;\n")
-               code.append("import " + valName + req.accessPath + ".`" + imv + "`;\n")
+                code.append("import " + valName + req.accessPath + ".`" + imv + "`;\n")
             }
             // code.append("val " + valName + " = " + objName + ".INSTANCE;\n")
             // code.append("import " + valName + req.accessPath + ".`" + imv + "`;\n")
@@ -211,10 +222,4 @@ trait SparkImports {
   private def membersAtPickler(sym: Symbol): List[Symbol] =
     beforePickler(sym.info.nonPrivateMembers.toList)
 
-  private var curValId = 0
-
-  private def newValId(): Int = {
-    curValId += 1
-    curValId
-  }
 }

repl/src/test/scala/org/apache/spark/repl/ReplSuite.scala

@@ -235,6 +235,18 @@ class ReplSuite extends FunSuite {
     assertContains("res4: Array[Int] = Array(0, 0, 0, 0, 0)", output)
   }
 
+  test("SPARK-1199-simple-reproduce") {
+    val output = runInterpreter("local-cluster[1,1,512]",
+      """
+        |case class Sum(exp: String, exp2: String)
+        |val a = Sum("A", "B")
+        |def b(a: Sum): String = a match { case Sum(_, _) => "Found Sum" }
+        |b(a)
+      """.stripMargin)
+    assertDoesNotContain("error:", output)
+    assertDoesNotContain("Exception", output)
+  }
+
   if (System.getenv("MESOS_NATIVE_LIBRARY") != null) {
     test("running on Mesos") {
       val output = runInterpreter("localquiet",