[SPARK-7977] [BUILD] Disallowing println

Author: Jonathan Alter <jonalter@users.noreply.github.com>

Closes #7093 from jonalter/SPARK-7977 and squashes the following commits:

ccd44cc [Jonathan Alter] Changed println to log in ThreadingSuite
7fcac3e [Jonathan Alter] Reverting to println in ThreadingSuite
10724b6 [Jonathan Alter] Changing some printlns to logs in tests
eeec1e7 [Jonathan Alter] Merge branch 'master' of github.com:apache/spark into SPARK-7977
0b1dcb4 [Jonathan Alter] More println cleanup
aedaf80 [Jonathan Alter] Merge branch 'master' of github.com:apache/spark into SPARK-7977
925fd98 [Jonathan Alter] Merge branch 'master' of github.com:apache/spark into SPARK-7977
0c16fa3 [Jonathan Alter] Replacing some printlns with logs
45c7e05 [Jonathan Alter] Merge branch 'master' of github.com:apache/spark into SPARK-7977
5c8e283 [Jonathan Alter] Allowing println in audit-release examples
5b50da1 [Jonathan Alter] Allowing printlns in example files
ca4b477 [Jonathan Alter] Merge branch 'master' of github.com:apache/spark into SPARK-7977
83ab635 [Jonathan Alter] Fixing new printlns
54b131f [Jonathan Alter] Merge branch 'master' of github.com:apache/spark into SPARK-7977
1cd8a81 [Jonathan Alter] Removing some unnecessary comments and printlns
b837c3a [Jonathan Alter] Disallowing println

3 files changed, 16 insertions, 8 deletions

diff --git a/sql/core/src/main/scala/org/apache/spark/sql/Column.scala b/sql/core/src/main/scala/org/apache/spark/sql/Column.scala
index f201c8ea8a..1025026462 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/Column.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/Column.scala
@@ -860,11 +860,13 @@ class Column(protected[sql] val expr: Expression) extends Logging {
    * @since 1.3.0
    */
   def explain(extended: Boolean): Unit = {
+    // scalastyle:off println
     if (extended) {
       println(expr)
     } else {
       println(expr.prettyString)
     }
+    // scalastyle:on println
   }
 
   /**
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/DataFrame.scala b/sql/core/src/main/scala/org/apache/spark/sql/DataFrame.scala
index d7966651b1..830fba35bb 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/DataFrame.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/DataFrame.scala
@@ -308,7 +308,9 @@ class DataFrame private[sql](
    * @group basic
    * @since 1.3.0
    */
+  // scalastyle:off println
   def printSchema(): Unit = println(schema.treeString)
+  // scalastyle:on println
 
   /**
    * Prints the plans (logical and physical) to the console for debugging purposes.
@@ -319,7 +321,9 @@ class DataFrame private[sql](
     ExplainCommand(
       queryExecution.logical,
       extended = extended).queryExecution.executedPlan.executeCollect().map {
+      // scalastyle:off println
       r => println(r.getString(0))
+      // scalastyle:on println
     }
   }
 
@@ -392,7 +396,9 @@ class DataFrame private[sql](
    * @group action
    * @since 1.5.0
    */
+  // scalastyle:off println
   def show(numRows: Int, truncate: Boolean): Unit = println(showString(numRows, truncate))
+  // scalastyle:on println
 
   /**
    * Returns a [[DataFrameNaFunctions]] for working with missing data.
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/debug/package.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/debug/package.scala
index 2964edac1a..e6081cb05b 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/debug/package.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/debug/package.scala
@@ -24,7 +24,7 @@ import org.apache.spark.unsafe.types.UTF8String
 
 import scala.collection.mutable.HashSet
 
-import org.apache.spark.{AccumulatorParam, Accumulator}
+import org.apache.spark.{AccumulatorParam, Accumulator, Logging}
 import org.apache.spark.annotation.DeveloperApi
 import org.apache.spark.sql._
 import org.apache.spark.sql.catalyst.trees.TreeNodeRef
@@ -57,7 +57,7 @@ package object debug {
    * Augments [[DataFrame]]s with debug methods.
    */
   @DeveloperApi
-  implicit class DebugQuery(query: DataFrame) {
+  implicit class DebugQuery(query: DataFrame) extends Logging {
     def debug(): Unit = {
       val plan = query.queryExecution.executedPlan
       val visited = new collection.mutable.HashSet[TreeNodeRef]()
@@ -66,7 +66,7 @@ package object debug {
           visited += new TreeNodeRef(s)
           DebugNode(s)
       }
-      println(s"Results returned: ${debugPlan.execute().count()}")
+      logDebug(s"Results returned: ${debugPlan.execute().count()}")
       debugPlan.foreach {
         case d: DebugNode => d.dumpStats()
         case _ =>
@@ -82,11 +82,11 @@ package object debug {
           TypeCheck(s)
       }
       try {
-        println(s"Results returned: ${debugPlan.execute().count()}")
+        logDebug(s"Results returned: ${debugPlan.execute().count()}")
       } catch {
         case e: Exception =>
           def unwrap(e: Throwable): Throwable = if (e.getCause == null) e else unwrap(e.getCause)
-          println(s"Deepest Error: ${unwrap(e)}")
+          logDebug(s"Deepest Error: ${unwrap(e)}")
       }
     }
   }
@@ -119,11 +119,11 @@ package object debug {
     val columnStats: Array[ColumnMetrics] = Array.fill(child.output.size)(new ColumnMetrics())
 
     def dumpStats(): Unit = {
-      println(s"== ${child.simpleString} ==")
-      println(s"Tuples output: ${tupleCount.value}")
+      logDebug(s"== ${child.simpleString} ==")
+      logDebug(s"Tuples output: ${tupleCount.value}")
       child.output.zip(columnStats).foreach { case(attr, metric) =>
         val actualDataTypes = metric.elementTypes.value.mkString("{", ",", "}")
-        println(s" ${attr.name} ${attr.dataType}: $actualDataTypes")
+        logDebug(s" ${attr.name} ${attr.dataType}: $actualDataTypes")
       }
     }