[SPARK-6429] Implement hashCode and equals together

core/src/main/scala/org/apache/spark/Partition.scala

@@ -28,4 +28,6 @@ trait Partition extends Serializable {
 
   // A better default implementation of HashCode
   override def hashCode(): Int = index
+
+  override def equals(other: Any): Boolean = super.equals(other)
 }

core/src/main/scala/org/apache/spark/rdd/CoGroupedRDD.scala

@@ -58,10 +58,10 @@ private[spark] case class NarrowCoGroupSplitDep(
  *                   narrowDeps should always be equal to the number of parents.
  */
 private[spark] class CoGroupPartition(
-    idx: Int, val narrowDeps: Array[Option[NarrowCoGroupSplitDep]])
+    override val index: Int, val narrowDeps: Array[Option[NarrowCoGroupSplitDep]])
   extends Partition with Serializable {
-  override val index: Int = idx
-  override def hashCode(): Int = idx
+  override def hashCode(): Int = index
+  override def equals(other: Any): Boolean = super.equals(other)
 }
 
 /**

core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala

@@ -53,14 +53,14 @@ import org.apache.spark.util.{NextIterator, SerializableConfiguration, ShutdownH
 /**
  * A Spark split class that wraps around a Hadoop InputSplit.
  */
-private[spark] class HadoopPartition(rddId: Int, idx: Int, s: InputSplit)
+private[spark] class HadoopPartition(rddId: Int, override val index: Int, s: InputSplit)
   extends Partition {
 
   val inputSplit = new SerializableWritable[InputSplit](s)
 
-  override def hashCode(): Int = 41 * (41 + rddId) + idx
+  override def hashCode(): Int = 31 * (31 + rddId) + index
 
-  override val index: Int = idx
+  override def equals(other: Any): Boolean = super.equals(other)
 
   /**
    * Get any environment variables that should be added to the users environment when running pipes

core/src/main/scala/org/apache/spark/rdd/NewHadoopRDD.scala

@@ -45,7 +45,10 @@ private[spark] class NewHadoopPartition(
   extends Partition {
 
   val serializableHadoopSplit = new SerializableWritable(rawSplit)
-  override def hashCode(): Int = 41 * (41 + rddId) + index
+
+  override def hashCode(): Int = 31 * (31 + rddId) + index
+
+  override def equals(other: Any): Boolean = super.equals(other)
 }
 
 /**

core/src/main/scala/org/apache/spark/rdd/PartitionerAwareUnionRDD.scala

@@ -31,12 +31,13 @@ import org.apache.spark.util.Utils
 private[spark]
 class PartitionerAwareUnionRDDPartition(
     @transient val rdds: Seq[RDD[_]],
-    val idx: Int
+    override val index: Int
   ) extends Partition {
-  var parents = rdds.map(_.partitions(idx)).toArray
+  var parents = rdds.map(_.partitions(index)).toArray
 
-  override val index = idx
-  override def hashCode(): Int = idx
+  override def hashCode(): Int = index
+
+  override def equals(other: Any): Boolean = super.equals(other)
 
   @throws(classOf[IOException])
   private def writeObject(oos: ObjectOutputStream): Unit = Utils.tryOrIOException {

core/src/main/scala/org/apache/spark/rdd/ShuffledRDD.scala

@@ -25,7 +25,10 @@ import org.apache.spark.serializer.Serializer
 
 private[spark] class ShuffledRDDPartition(val idx: Int) extends Partition {
   override val index: Int = idx
-  override def hashCode(): Int = idx
+
+  override def hashCode(): Int = index
+
+  override def equals(other: Any): Boolean = super.equals(other)
 }
 
 /**

core/src/test/scala/org/apache/spark/scheduler/CustomShuffledRDD.scala

@@ -18,6 +18,7 @@
 package org.apache.spark.scheduler
 
 import java.util.Arrays
+import java.util.Objects
 
 import org.apache.spark._
 import org.apache.spark.rdd.RDD
@@ -53,6 +54,9 @@ class CoalescedPartitioner(val parent: Partitioner, val partitionStartIndices: A
     parentPartitionMapping(parent.getPartition(key))
   }
 
+  override def hashCode(): Int =
+    31 * Objects.hashCode(parent) + Arrays.hashCode(partitionStartIndices)
+
   override def equals(other: Any): Boolean = other match {
     case c: CoalescedPartitioner =>
       c.parent == parent && Arrays.equals(c.partitionStartIndices, partitionStartIndices)
@@ -66,6 +70,8 @@ private[spark] class CustomShuffledRDDPartition(
   extends Partition {
 
   override def hashCode(): Int = index
+
+  override def equals(other: Any): Boolean = super.equals(other)
 }
 
 /**

core/src/test/scala/org/apache/spark/serializer/KryoSerializerSuite.scala

@@ -476,13 +476,18 @@ object KryoTest {
 
   class ClassWithNoArgConstructor {
     var x: Int = 0
+
+    override def hashCode(): Int = x
+
     override def equals(other: Any): Boolean = other match {
       case c: ClassWithNoArgConstructor => x == c.x
       case _ => false
     }
   }
 
   class ClassWithoutNoArgConstructor(val x: Int) {
+    override def hashCode(): Int = x
+
     override def equals(other: Any): Boolean = other match {
       case c: ClassWithoutNoArgConstructor => x == c.x
       case _ => false

core/src/test/scala/org/apache/spark/util/ClosureCleanerSuite.scala

@@ -124,6 +124,8 @@ class ClosureCleanerSuite extends SparkFunSuite {
 // A non-serializable class we create in closures to make sure that we aren't
 // keeping references to unneeded variables from our outer closures.
 class NonSerializable(val id: Int = -1) {
+  override def hashCode(): Int = id
+
   override def equals(other: Any): Boolean = {
     other match {
       case o: NonSerializable => id == o.id

core/src/test/scala/org/apache/spark/util/collection/FixedHashObject.scala

@@ -22,4 +22,8 @@ package org.apache.spark.util.collection
  */
 case class FixedHashObject(v: Int, h: Int) extends Serializable {
   override def hashCode(): Int = h
+  override def equals(other: Any): Boolean = other match {
+    case that: FixedHashObject => v == that.v && h == that.h
+    case _ => false
+  }
 }

mllib-local/src/main/scala/org/apache/spark/ml/linalg/Matrices.scala

@@ -458,6 +458,8 @@ class SparseMatrix (
       rowIndices: Array[Int],
       values: Array[Double]) = this(numRows, numCols, colPtrs, rowIndices, values, false)
 
+  override def hashCode(): Int = toBreeze.hashCode()
+
   override def equals(o: Any): Boolean = o match {
     case m: Matrix => toBreeze == m.toBreeze
     case _ => false

mllib-local/src/main/scala/org/apache/spark/ml/linalg/Vectors.scala

@@ -476,6 +476,8 @@ class DenseVector (val values: Array[Double]) extends Vector {
     }
   }
 
+  override def equals(other: Any): Boolean = super.equals(other)
+
   override def hashCode(): Int = {
     var result: Int = 31 + size
     var i = 0
@@ -602,6 +604,8 @@ class SparseVector (
     }
   }
 
+  override def equals(other: Any): Boolean = super.equals(other)
+
   override def hashCode(): Int = {
     var result: Int = 31 + size
     val end = values.length

mllib/src/main/scala/org/apache/spark/ml/tree/Split.scala

@@ -17,6 +17,8 @@
 
 package org.apache.spark.ml.tree
 
+import java.util.Objects
+
 import org.apache.spark.annotation.{DeveloperApi, Since}
 import org.apache.spark.mllib.linalg.Vector
 import org.apache.spark.mllib.tree.configuration.{FeatureType => OldFeatureType}
@@ -112,12 +114,15 @@ final class CategoricalSplit private[ml] (
     }
   }
 
-  override def equals(o: Any): Boolean = {
-    o match {
-      case other: CategoricalSplit => featureIndex == other.featureIndex &&
-        isLeft == other.isLeft && categories == other.categories
-      case _ => false
-    }
+  override def hashCode(): Int = {
+    val state = Seq(featureIndex, isLeft, categories)
+    state.map(Objects.hashCode).foldLeft(0)((a, b) => 31 * a + b)
+  }
+
+  override def equals(o: Any): Boolean = o match {
+    case other: CategoricalSplit => featureIndex == other.featureIndex &&
+      isLeft == other.isLeft && categories == other.categories
+    case _ => false
   }
 
   override private[tree] def toOld: OldSplit = {
@@ -181,6 +186,11 @@ final class ContinuousSplit private[ml] (override val featureIndex: Int, val thr
     }
   }
 
+  override def hashCode(): Int = {
+    val state = Seq(featureIndex, threshold)
+    state.map(Objects.hashCode).foldLeft(0)((a, b) => 31 * a + b)
+  }
+
   override private[tree] def toOld: OldSplit = {
     OldSplit(featureIndex, threshold, OldFeatureType.Continuous, List.empty[Double])
   }

mllib/src/main/scala/org/apache/spark/mllib/linalg/Matrices.scala

@@ -590,6 +590,8 @@ class SparseMatrix @Since("1.3.0") (
     case _ => false
   }
 
+  override def hashCode(): Int = toBreeze.hashCode
+
   private[mllib] def toBreeze: BM[Double] = {
      if (!isTransposed) {
        new BSM[Double](values, numRows, numCols, colPtrs, rowIndices)

mllib/src/main/scala/org/apache/spark/mllib/linalg/Vectors.scala

@@ -613,6 +613,8 @@ class DenseVector @Since("1.0.0") (
     }
   }
 
+  override def equals(other: Any): Boolean = super.equals(other)
+
   override def hashCode(): Int = {
     var result: Int = 31 + size
     var i = 0
@@ -751,6 +753,8 @@ class SparseVector @Since("1.0.0") (
     }
   }
 
+  override def equals(other: Any): Boolean = super.equals(other)
+
   override def hashCode(): Int = {
     var result: Int = 31 + size
     val end = values.length

project/MimaExcludes.scala

@@ -113,6 +113,10 @@ object MimaExcludes {
         ProblemFilters.exclude[MissingMethodProblem](
           "org.apache.spark.api.java.function.FlatMapGroupsFunction.call")
       ) ++
+      Seq(
+        // [SPARK-6429] Implement hashCode and equals together
+        ProblemFilters.exclude[ReversedMissingMethodProblem]("org.apache.spark.Partition.org$apache$spark$Partition$$super=uals")
+      ) ++
       Seq(
         // SPARK-4819 replace Guava Optional
         ProblemFilters.exclude[IncompatibleResultTypeProblem]("org.apache.spark.api.java.JavaSparkContext.getCheckpointDir"),

scalastyle-config.xml

@@ -262,7 +262,7 @@ This file is divided into 3 sections:
   </check>
 
   <!-- Should turn this on, but we have a few places that need to be fixed first -->
-  <check level="error" class="org.scalastyle.scalariform.EqualsHashCodeChecker" enabled="false"></check>
+  <check level="error" class="org.scalastyle.scalariform.EqualsHashCodeChecker" enabled="true"></check>
 
   <!-- ================================================================================ -->
   <!--                               rules we don't want                                -->

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/AttributeSet.scala

@@ -60,6 +60,8 @@ object AttributeSet {
 class AttributeSet private (val baseSet: Set[AttributeEquals])
   extends Traversable[Attribute] with Serializable {
 
+  override def hashCode: Int = baseSet.hashCode()
+
   /** Returns true if the members of this AttributeSet and other are the same. */
   override def equals(other: Any): Boolean = other match {
     case otherSet: AttributeSet =>

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/EquivalentExpressions.scala

@@ -35,7 +35,8 @@ class EquivalentExpressions {
       case other: Expr => e.semanticEquals(other.e)
       case _ => false
     }
-    override val hashCode: Int = e.semanticHash()
+
+    override def hashCode: Int = e.semanticHash()
   }
 
   // For each expression, the set of equivalent expressions.

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/literals.scala

@@ -19,6 +19,7 @@ package org.apache.spark.sql.catalyst.expressions
 
 import java.nio.charset.StandardCharsets
 import java.sql.{Date, Timestamp}
+import java.util.Objects
 
 import org.json4s.JsonAST._
 
@@ -170,6 +171,8 @@ case class Literal protected (value: Any, dataType: DataType)
 
   override def toString: String = if (value != null) value.toString else "null"
 
+  override def hashCode(): Int = 31 * (31 * Objects.hashCode(dataType)) + Objects.hashCode(value)
+
   override def equals(other: Any): Boolean = other match {
     case o: Literal =>
       dataType.equals(o.dataType) &&

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/namedExpressions.scala

@@ -17,7 +17,7 @@
 
 package org.apache.spark.sql.catalyst.expressions
 
-import java.util.UUID
+import java.util.{Objects, UUID}
 
 import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.catalyst.analysis.UnresolvedAttribute
@@ -175,6 +175,11 @@ case class Alias(child: Expression, name: String)(
     exprId :: qualifier :: explicitMetadata :: isGenerated :: Nil
   }
 
+  override def hashCode(): Int = {
+    val state = Seq(name, exprId, child, qualifier, explicitMetadata)
+    state.map(Objects.hashCode).foldLeft(0)((a, b) => 31 * a + b)
+  }
+
   override def equals(other: Any): Boolean = other match {
     case a: Alias =>
       name == a.name && exprId == a.exprId && child == a.child && qualifier == a.qualifier &&

sql/catalyst/src/main/scala/org/apache/spark/sql/types/UserDefinedType.scala

@@ -17,6 +17,8 @@
 
 package org.apache.spark.sql.types
 
+import java.util.Objects
+
 import org.json4s.JsonAST.JValue
 import org.json4s.JsonDSL._
 
@@ -83,6 +85,8 @@ abstract class UserDefinedType[UserType >: Null] extends DataType with Serializa
 
   override def sql: String = sqlType.sql
 
+  override def hashCode(): Int = getClass.hashCode()
+
   override def equals(other: Any): Boolean = other match {
     case that: UserDefinedType[_] => this.acceptsType(that)
     case _ => false
@@ -115,7 +119,9 @@ private[sql] class PythonUserDefinedType(
   }
 
   override def equals(other: Any): Boolean = other match {
-    case that: PythonUserDefinedType => this.pyUDT.equals(that.pyUDT)
+    case that: PythonUserDefinedType => pyUDT == that.pyUDT
     case _ => false
   }
+
+  override def hashCode(): Int = Objects.hashCode(pyUDT)
 }

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/encoders/ExpressionEncoderSuite.scala

@@ -35,6 +35,9 @@ import org.apache.spark.sql.types.{ArrayType, Decimal, ObjectType, StructType}
 case class RepeatedStruct(s: Seq[PrimitiveData])
 
 case class NestedArray(a: Array[Array[Int]]) {
+  override def hashCode(): Int =
+    java.util.Arrays.deepHashCode(a.asInstanceOf[Array[AnyRef]])
+
   override def equals(other: Any): Boolean = other match {
     case NestedArray(otherArray) =>
       java.util.Arrays.deepEquals(
@@ -64,15 +67,21 @@ case class SpecificCollection(l: List[Int])
 
 /** For testing Kryo serialization based encoder. */
 class KryoSerializable(val value: Int) {
-  override def equals(other: Any): Boolean = {
-    this.value == other.asInstanceOf[KryoSerializable].value
+  override def hashCode(): Int = value
+
+  override def equals(other: Any): Boolean = other match {
+    case that: KryoSerializable => this.value == that.value
+    case _ => false
   }
 }
 
 /** For testing Java serialization based encoder. */
 class JavaSerializable(val value: Int) extends Serializable {
-  override def equals(other: Any): Boolean = {
-    this.value == other.asInstanceOf[JavaSerializable].value
+  override def hashCode(): Int = value
+
+  override def equals(other: Any): Boolean = other match {
+    case that: JavaSerializable => this.value == that.value
+    case _ => false
   }
 }
 

sql/core/src/main/scala/org/apache/spark/sql/execution/ShuffledRowRDD.scala

@@ -33,7 +33,10 @@ private final class ShuffledRowRDDPartition(
     val startPreShufflePartitionIndex: Int,
     val endPreShufflePartitionIndex: Int) extends Partition {
   override val index: Int = postShufflePartitionIndex
+
   override def hashCode(): Int = postShufflePartitionIndex
+
+  override def equals(other: Any): Boolean = super.equals(other)
 }
 
 /**