[jvm-packages] update scala style configuration (#10836)

jvm-packages/scalastyle-config.xml

@@ -82,19 +82,27 @@ This file is divided into 3 sections:
   </check>
 
   <check level="error" class="org.scalastyle.scalariform.ClassNamesChecker" enabled="true">
-    <parameters><parameter name="regex"><![CDATA[[A-Z][A-Za-z]*]]></parameter></parameters>
+    <parameters>
+      <parameter name="regex"><![CDATA[[A-Z][A-Za-z]*]]></parameter>
+    </parameters>
   </check>
 
   <check level="error" class="org.scalastyle.scalariform.ObjectNamesChecker" enabled="true">
-    <parameters><parameter name="regex"><![CDATA[[A-Z][A-Za-z]*]]></parameter></parameters>
+    <parameters>
+      <parameter name="regex"><![CDATA[[A-Z][A-Za-z]*]]></parameter>
+    </parameters>
   </check>
 
   <check level="error" class="org.scalastyle.scalariform.PackageObjectNamesChecker" enabled="true">
-    <parameters><parameter name="regex"><![CDATA[^[a-z][A-Za-z]*$]]></parameter></parameters>
+    <parameters>
+      <parameter name="regex"><![CDATA[^[a-z][A-Za-z]*$]]></parameter>
+    </parameters>
   </check>
 
   <check level="error" class="org.scalastyle.scalariform.ParameterNumberChecker" enabled="true">
-    <parameters><parameter name="maxParameters"><![CDATA[10]]></parameter></parameters>
+    <parameters>
+      <parameter name="maxParameters"><![CDATA[10]]></parameter>
+    </parameters>
   </check>
 
   <check level="error" class="org.scalastyle.scalariform.NoFinalizeChecker" enabled="false"></check>
@@ -121,14 +129,16 @@ This file is divided into 3 sections:
   <check level="error" class="org.scalastyle.scalariform.SpaceAfterCommentStartChecker" enabled="true"></check>
 
   <check level="error" class="org.scalastyle.scalariform.EnsureSingleSpaceBeforeTokenChecker" enabled="true">
-   <parameters>
+    <parameters>
-     <parameter name="tokens">ARROW, EQUALS, ELSE, TRY, CATCH, FINALLY, LARROW, RARROW</parameter>
+      <parameter name="tokens">ARROW, EQUALS, ELSE, TRY, CATCH, FINALLY, LARROW, RARROW</parameter>
-   </parameters>
+    </parameters>
   </check>
 
   <check level="error" class="org.scalastyle.scalariform.EnsureSingleSpaceAfterTokenChecker" enabled="true">
     <parameters>
-     <parameter name="tokens">ARROW, EQUALS, COMMA, COLON, IF, ELSE, DO, WHILE, FOR, MATCH, TRY, CATCH, FINALLY, LARROW, RARROW</parameter>
+      <parameter name="tokens">ARROW, EQUALS, COMMA, COLON, IF, ELSE, DO, WHILE, FOR, MATCH, TRY, CATCH, FINALLY,
+        LARROW, RARROW
+      </parameter>
     </parameters>
   </check>
 
@@ -136,14 +146,18 @@ This file is divided into 3 sections:
   <check level="error" class="org.scalastyle.scalariform.NotImplementedErrorUsage" enabled="true"></check>
 
   <check customId="visiblefortesting" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
-    <parameters><parameter name="regex">@VisibleForTesting</parameter></parameters>
+    <parameters>
+      <parameter name="regex">@VisibleForTesting</parameter>
+    </parameters>
     <customMessage><![CDATA[
       @VisibleForTesting causes classpath issues. Please note this in the java doc instead (SPARK-11615).
     ]]></customMessage>
   </check>
 
   <check customId="runtimeaddshutdownhook" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
-    <parameters><parameter name="regex">Runtime\.getRuntime\.addShutdownHook</parameter></parameters>
+    <parameters>
+      <parameter name="regex">Runtime\.getRuntime\.addShutdownHook</parameter>
+    </parameters>
     <customMessage><![CDATA[
       Are you sure that you want to use Runtime.getRuntime.addShutdownHook? In most cases, you should use
       ShutdownHookManager.addShutdownHook instead.
@@ -155,7 +169,9 @@ This file is divided into 3 sections:
   </check>
 
   <check customId="mutablesynchronizedbuffer" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
-    <parameters><parameter name="regex">mutable\.SynchronizedBuffer</parameter></parameters>
+    <parameters>
+      <parameter name="regex">mutable\.SynchronizedBuffer</parameter>
+    </parameters>
     <customMessage><![CDATA[
       Are you sure that you want to use mutable.SynchronizedBuffer? In most cases, you should use
       java.util.concurrent.ConcurrentLinkedQueue instead.
@@ -167,7 +183,9 @@ This file is divided into 3 sections:
   </check>
 
   <check customId="classforname" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
-    <parameters><parameter name="regex">Class\.forName</parameter></parameters>
+    <parameters>
+      <parameter name="regex">Class\.forName</parameter>
+    </parameters>
     <customMessage><![CDATA[
       Are you sure that you want to use Class.forName? In most cases, you should use Utils.classForName instead.
       If you must use Class.forName, wrap the code block with
@@ -179,17 +197,20 @@ This file is divided into 3 sections:
 
   <!-- As of SPARK-9613 JavaConversions should be replaced with JavaConverters -->
   <check customId="javaconversions" level="error" class="org.scalastyle.scalariform.TokenChecker" enabled="true">
-    <parameters><parameter name="regex">JavaConversions</parameter></parameters>
+    <parameters>
+      <parameter name="regex">JavaConversions</parameter>
+    </parameters>
     <customMessage>Instead of importing implicits in scala.collection.JavaConversions._, import
-    scala.collection.JavaConverters._ and use .asScala / .asJava methods</customMessage>
+      scala.collection.JavaConverters._ and use .asScala / .asJava methods
+    </customMessage>
   </check>
 
   <check level="error" class="org.scalastyle.scalariform.ImportOrderChecker" enabled="true">
     <parameters>
-      <parameter name="groups">java,scala,3rdParty,spark</parameter>
+      <parameter name="groups">java,scala,3rdParty,dmlc</parameter>
       <parameter name="group.java">javax?\..*</parameter>
       <parameter name="group.scala">scala\..*</parameter>
-      <parameter name="group.3rdParty">(?!ml\.dmlc\.xgboost4j\.).*</parameter>
+      <parameter name="group.3rdParty">(?!ml\.dmlc\.xgboost4j).*</parameter>
       <parameter name="group.dmlc">ml.dmlc.xgboost4j.*</parameter>
     </parameters>
   </check>
@@ -213,7 +234,7 @@ This file is divided into 3 sections:
   <!-- Maybe we should update it to allow basic symbolic names, and then we are good to go. -->
   <check level="error" class="org.scalastyle.scalariform.MethodNamesChecker" enabled="false">
     <parameters>
-    <parameter name="regex"><![CDATA[^[a-z][A-Za-z0-9]*$]]></parameter>
+      <parameter name="regex"><![CDATA[^[a-z][A-Za-z0-9]*$]]></parameter>
     </parameters>
   </check>
 
@@ -225,7 +246,9 @@ This file is divided into 3 sections:
   <!-- ================================================================================ -->
 
   <check level="error" class="org.scalastyle.scalariform.IllegalImportsChecker" enabled="false">
-    <parameters><parameter name="illegalImports"><![CDATA[sun._,java.awt._]]></parameter></parameters>
+    <parameters>
+      <parameter name="illegalImports"><![CDATA[sun._,java.awt._]]></parameter>
+    </parameters>
   </check>
 
   <!-- We want the opposite of this: NewLineAtEofChecker -->
@@ -245,33 +268,81 @@ This file is divided into 3 sections:
 
   <!-- Doesn't seem super big deal here ... -->
   <check level="error" class="org.scalastyle.file.FileLengthChecker" enabled="false">
-    <parameters><parameter name="maxFileLength">800></parameter></parameters>
+    <parameters>
+      <parameter name="maxFileLength">800></parameter>
+    </parameters>
   </check>
 
   <!-- Doesn't seem super big deal here ... -->
   <check level="error" class="org.scalastyle.scalariform.NumberOfTypesChecker" enabled="false">
-    <parameters><parameter name="maxTypes">30</parameter></parameters>
+    <parameters>
+      <parameter name="maxTypes">30</parameter>
+    </parameters>
   </check>
 
   <!-- Doesn't seem super big deal here ... -->
   <check level="error" class="org.scalastyle.scalariform.CyclomaticComplexityChecker" enabled="false">
-    <parameters><parameter name="maximum">10</parameter></parameters>
+    <parameters>
+      <parameter name="maximum">10</parameter>
+    </parameters>
   </check>
 
   <!-- Doesn't seem super big deal here ... -->
   <check level="error" class="org.scalastyle.scalariform.MethodLengthChecker" enabled="false">
-    <parameters><parameter name="maxLength">50</parameter></parameters>
+    <parameters>
+      <parameter name="maxLength">50</parameter>
+    </parameters>
   </check>
 
   <!-- Not exactly feasible to enforce this right now. -->
   <!-- It is also infrequent that somebody introduces a new class with a lot of methods. -->
   <check level="error" class="org.scalastyle.scalariform.NumberOfMethodsInTypeChecker" enabled="false">
-    <parameters><parameter name="maxMethods"><![CDATA[30]]></parameter></parameters>
+    <parameters>
+      <parameter name="maxMethods"><![CDATA[30]]></parameter>
+    </parameters>
   </check>
 
   <!-- Doesn't seem super big deal here, and we have a lot of magic numbers ... -->
   <check level="error" class="org.scalastyle.scalariform.MagicNumberChecker" enabled="false">
-    <parameters><parameter name="ignore">-1,0,1,2,3</parameter></parameters>
+    <parameters>
+      <parameter name="ignore">-1,0,1,2,3</parameter>
+    </parameters>
   </check>
 
+  <check level="error" class="org.scalastyle.scalariform.IllegalImportsChecker" enabled="true">
+    <parameters>
+      <parameter name="illegalImports"><![CDATA[scala.collection.Seq,scala.collection.IndexedSeq]]></parameter>
+    </parameters>
+    <customMessage><![CDATA[
+        Don't import scala.collection.Seq and scala.collection.IndexedSeq as it may cause issues with cross-build between Scala 2.12 and 2.13.
+
+        Please refer below page to see the details of changes around Seq / IndexedSeq.
+        https://docs.scala-lang.org/overviews/core/collections-migration-213.html
+
+        If you really need to use scala.collection.Seq or scala.collection.IndexedSeq, please use the fully-qualified name instead.
+        ]]></customMessage>
+  </check>
+  <check level="error" class="org.scalastyle.scalariform.ProcedureDeclarationChecker" enabled="true">
+    <customMessage>procedure syntax is deprecated in Scala 2.13: add return type `: Unit` and `=`</customMessage>
+  </check>
+  <check level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
+    <parameters>
+      <parameter name="regex">ArrayBuilder.make\[(.+)\]\(\)</parameter>
+      <parameter name="line">false</parameter>
+    </parameters>
+    <customMessage>ArrayBuilder.make does not accept parens anymore in Scala 2.13</customMessage>
+  </check>
+
+  <check level="warning" class="org.scalastyle.file.RegexChecker" enabled="false">
+    <parameters>
+      <parameter name="regex">(: |\[)(Indexed)?Seq\[[A-Za-z0-9_]+\]</parameter>
+      <parameter name="line">false</parameter>
+    </parameters>
+    <customMessage><![CDATA[NOTE: Scala 2.12 defaults scala.(Indexed)Seq to scala.collection.(Indexed)Seq while Scala 2.13 defaults
+        scala.(Indexed)Seq to scala.collection.immutable.(Indexed)Seq
+
+        Please refer below page to see the details of changes around Seq / IndexedSeq.
+        https://docs.scala-lang.org/overviews/core/collections-migration-213.html
+        ]]></customMessage>
+  </check>
 </scalastyle>

jvm-packages/xgboost4j-spark-gpu/src/main/scala/ml/dmlc/xgboost4j/scala/QuantileDMatrix.scala

@@ -16,10 +16,10 @@
 
 package ml.dmlc.xgboost4j.scala
 
-import ml.dmlc.xgboost4j.java.{Column, ColumnBatch, XGBoostError, QuantileDMatrix => JQuantileDMatrix}
-
 import scala.collection.JavaConverters._
 
+import ml.dmlc.xgboost4j.java.{Column, ColumnBatch, QuantileDMatrix => JQuantileDMatrix, XGBoostError}
+
 class QuantileDMatrix private[scala](
     private[scala] override val jDMatrix: JQuantileDMatrix) extends DMatrix(jDMatrix) {
 

jvm-packages/xgboost4j-spark-gpu/src/test/resources/log4j.properties

@@ -0,0 +1 @@
+log4j.logger.org.apache.spark=INFO

jvm-packages/xgboost4j-spark-gpu/src/test/scala/ml/dmlc/xgboost4j/scala/spark/GpuTestSuite.scala

@@ -17,13 +17,12 @@
 package ml.dmlc.xgboost4j.scala.rapids.spark
 
 import java.nio.file.{Files, Path}
-import java.sql.{Date, Timestamp}
 import java.util.{Locale, TimeZone}
 
 import org.apache.spark.{GpuTestUtils, SparkConf}
 import org.apache.spark.internal.Logging
 import org.apache.spark.network.util.JavaUtils
-import org.apache.spark.sql.{Row, SparkSession}
+import org.apache.spark.sql.SparkSession
 import org.scalatest.BeforeAndAfterAll
 import org.scalatest.funsuite.AnyFunSuite
 

jvm-packages/xgboost4j-spark-gpu/src/test/scala/ml/dmlc/xgboost4j/scala/spark/GpuXGBoostPluginSuite.scala

@@ -16,18 +16,20 @@
 
 package ml.dmlc.xgboost4j.scala.spark
 
+import java.io.File
+
+import scala.collection.mutable.ArrayBuffer
+
 import ai.rapids.cudf.{OrderByArg, Table}
+import org.apache.spark.SparkConf
+import org.apache.spark.ml.linalg.DenseVector
+import org.apache.spark.sql.{Dataset, Row, SparkSession}
+
 import ml.dmlc.xgboost4j.java.CudfColumnBatch
 import ml.dmlc.xgboost4j.scala.{DMatrix, QuantileDMatrix, XGBoost => ScalaXGBoost}
 import ml.dmlc.xgboost4j.scala.rapids.spark.GpuTestSuite
 import ml.dmlc.xgboost4j.scala.rapids.spark.SparkSessionHolder.withSparkSession
 import ml.dmlc.xgboost4j.scala.spark.Utils.withResource
-import org.apache.spark.ml.linalg.DenseVector
-import org.apache.spark.sql.{Dataset, Row, SparkSession}
-import org.apache.spark.SparkConf
-
-import java.io.File
-import scala.collection.mutable.ArrayBuffer
 
 class GpuXGBoostPluginSuite extends GpuTestSuite {
 

jvm-packages/xgboost4j-spark/src/main/scala/ml/dmlc/xgboost4j/scala/spark/XGBoostRanker.scala

@@ -22,11 +22,12 @@ import org.apache.spark.ml.param.ParamMap
 import org.apache.spark.ml.util.{DefaultParamsReadable, Identifiable, MLReadable, MLReader}
 import org.apache.spark.ml.xgboost.SparkUtils
 import org.apache.spark.sql.Dataset
+import org.apache.spark.sql.types.{DataType, DoubleType, StructType}
+
 import ml.dmlc.xgboost4j.scala.Booster
 import ml.dmlc.xgboost4j.scala.spark.XGBoostRanker._uid
 import ml.dmlc.xgboost4j.scala.spark.params.HasGroupCol
 import ml.dmlc.xgboost4j.scala.spark.params.LearningTaskParams.RANKER_OBJS
-import org.apache.spark.sql.types.{DataType, DoubleType, StructType}
 
 class XGBoostRanker(override val uid: String,
                     private val xgboostParams: Map[String, Any])

jvm-packages/xgboost4j-spark/src/main/scala/ml/dmlc/xgboost4j/scala/spark/XGBoostRegressor.scala

@@ -22,11 +22,11 @@ import org.apache.spark.ml.param.ParamMap
 import org.apache.spark.ml.util.{DefaultParamsReadable, Identifiable, MLReadable, MLReader}
 import org.apache.spark.ml.xgboost.SparkUtils
 import org.apache.spark.sql.Dataset
+import org.apache.spark.sql.types.{DataType, DoubleType, StructType}
 
 import ml.dmlc.xgboost4j.scala.Booster
 import ml.dmlc.xgboost4j.scala.spark.XGBoostRegressor._uid
 import ml.dmlc.xgboost4j.scala.spark.params.LearningTaskParams.REGRESSION_OBJS
-import org.apache.spark.sql.types.{DataType, DoubleType, StructType}
 
 class XGBoostRegressor(override val uid: String,
                        private val xgboostParams: Map[String, Any])

jvm-packages/xgboost4j-spark/src/test/scala/ml/dmlc/xgboost4j/scala/spark/XGBoostEstimatorSuite.scala

@@ -18,10 +18,11 @@ package ml.dmlc.xgboost4j.scala.spark
 
 import java.io.File
 import java.util.Arrays
+
 import scala.collection.mutable.ArrayBuffer
 
-import org.apache.spark.ml.linalg.{DenseVector, SparseVector, Vectors}
 import org.apache.spark.SparkException
+import org.apache.spark.ml.linalg.{DenseVector, SparseVector, Vectors}
 import org.json4s.{DefaultFormats, Formats}
 import org.json4s.jackson.parseJson
 import org.scalatest.funsuite.AnyFunSuite