[SPARK-3873][BUILD] Enable import ordering error checking.

Turn import ordering violations into build errors, plus a few adjustments
to account for how the checker behaves. I'm a little on the fence about
whether the existing code is right, but it's easier to appease the checker
than to discuss what's the more correct order here.

Plus a few fixes to imports that cropped in since my recent cleanups.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #10612 from vanzin/SPARK-3873-enable.

5 files changed, 7 insertions, 8 deletions

diff --git a/mllib/src/main/scala/org/apache/spark/ml/tree/treeParams.scala b/mllib/src/main/scala/org/apache/spark/ml/tree/treeParams.scala
index 7443097492..7a651a37ac 100644
--- a/mllib/src/main/scala/org/apache/spark/ml/tree/treeParams.scala
+++ b/mllib/src/main/scala/org/apache/spark/ml/tree/treeParams.scala
@@ -24,7 +24,7 @@ import org.apache.spark.ml.util.SchemaUtils
 import org.apache.spark.mllib.tree.configuration.{Algo => OldAlgo, BoostingStrategy => OldBoostingStrategy, Strategy => OldStrategy}
 import org.apache.spark.mllib.tree.impurity.{Entropy => OldEntropy, Gini => OldGini, Impurity => OldImpurity, Variance => OldVariance}
 import org.apache.spark.mllib.tree.loss.{Loss => OldLoss}
-import org.apache.spark.sql.types.{DoubleType, DataType, StructType}
+import org.apache.spark.sql.types.{DataType, DoubleType, StructType}
 
 /**
  * Parameters for Decision Tree-based algorithms.
diff --git a/mllib/src/main/scala/org/apache/spark/mllib/fpm/FPGrowth.scala b/mllib/src/main/scala/org/apache/spark/mllib/fpm/FPGrowth.scala
index ffae0e7ed0..1250bc1a07 100644
--- a/mllib/src/main/scala/org/apache/spark/mllib/fpm/FPGrowth.scala
+++ b/mllib/src/main/scala/org/apache/spark/mllib/fpm/FPGrowth.scala
@@ -17,8 +17,8 @@
 
 package org.apache.spark.mllib.fpm
 
-import java.lang.{Iterable => JavaIterable}
 import java.{util => ju}
+import java.lang.{Iterable => JavaIterable}
 
 import scala.collection.JavaConverters._
 import scala.collection.mutable
@@ -29,16 +29,15 @@ import org.json4s.DefaultFormats
 import org.json4s.JsonDSL._
 import org.json4s.jackson.JsonMethods.{compact, render}
 
-import org.apache.spark.{HashPartitioner, Logging, Partitioner, SparkException}
+import org.apache.spark.{HashPartitioner, Logging, Partitioner, SparkContext, SparkException}
 import org.apache.spark.annotation.Since
 import org.apache.spark.api.java.JavaRDD
 import org.apache.spark.api.java.JavaSparkContext.fakeClassTag
 import org.apache.spark.mllib.fpm.FPGrowth._
 import org.apache.spark.mllib.util.{Loader, Saveable}
 import org.apache.spark.rdd.RDD
-import org.apache.spark.SparkContext
-import org.apache.spark.sql.catalyst.ScalaReflection
 import org.apache.spark.sql.{DataFrame, Row, SQLContext}
+import org.apache.spark.sql.catalyst.ScalaReflection
 import org.apache.spark.sql.types._
 import org.apache.spark.storage.StorageLevel
 
diff --git a/mllib/src/main/scala/org/apache/spark/mllib/tree/DecisionTree.scala b/mllib/src/main/scala/org/apache/spark/mllib/tree/DecisionTree.scala
index c73774fcd8..07ba0d8ccb 100644
--- a/mllib/src/main/scala/org/apache/spark/mllib/tree/DecisionTree.scala
+++ b/mllib/src/main/scala/org/apache/spark/mllib/tree/DecisionTree.scala
@@ -25,10 +25,10 @@ import org.apache.spark.annotation.Since
 import org.apache.spark.api.java.JavaRDD
 import org.apache.spark.mllib.regression.LabeledPoint
 import org.apache.spark.mllib.tree.RandomForest.NodeIndexInfo
-import org.apache.spark.mllib.tree.configuration.Strategy
 import org.apache.spark.mllib.tree.configuration.Algo._
 import org.apache.spark.mllib.tree.configuration.FeatureType._
 import org.apache.spark.mllib.tree.configuration.QuantileStrategy._
+import org.apache.spark.mllib.tree.configuration.Strategy
 import org.apache.spark.mllib.tree.impl._
 import org.apache.spark.mllib.tree.impurity._
 import org.apache.spark.mllib.tree.model._
diff --git a/mllib/src/main/scala/org/apache/spark/mllib/tree/GradientBoostedTrees.scala b/mllib/src/main/scala/org/apache/spark/mllib/tree/GradientBoostedTrees.scala
index 729a211574..1b71256c58 100644
--- a/mllib/src/main/scala/org/apache/spark/mllib/tree/GradientBoostedTrees.scala
+++ b/mllib/src/main/scala/org/apache/spark/mllib/tree/GradientBoostedTrees.scala
@@ -22,8 +22,8 @@ import org.apache.spark.annotation.Since
 import org.apache.spark.api.java.JavaRDD
 import org.apache.spark.mllib.impl.PeriodicRDDCheckpointer
 import org.apache.spark.mllib.regression.LabeledPoint
-import org.apache.spark.mllib.tree.configuration.BoostingStrategy
 import org.apache.spark.mllib.tree.configuration.Algo._
+import org.apache.spark.mllib.tree.configuration.BoostingStrategy
 import org.apache.spark.mllib.tree.impl.TimeTracker
 import org.apache.spark.mllib.tree.impurity.Variance
 import org.apache.spark.mllib.tree.model.{DecisionTreeModel, GradientBoostedTreesModel}
diff --git a/mllib/src/main/scala/org/apache/spark/mllib/tree/RandomForest.scala b/mllib/src/main/scala/org/apache/spark/mllib/tree/RandomForest.scala
index a684cdd18c..570a76f960 100644
--- a/mllib/src/main/scala/org/apache/spark/mllib/tree/RandomForest.scala
+++ b/mllib/src/main/scala/org/apache/spark/mllib/tree/RandomForest.scala
@@ -26,9 +26,9 @@ import org.apache.spark.Logging
 import org.apache.spark.annotation.Since
 import org.apache.spark.api.java.JavaRDD
 import org.apache.spark.mllib.regression.LabeledPoint
-import org.apache.spark.mllib.tree.configuration.Strategy
 import org.apache.spark.mllib.tree.configuration.Algo._
 import org.apache.spark.mllib.tree.configuration.QuantileStrategy._
+import org.apache.spark.mllib.tree.configuration.Strategy
 import org.apache.spark.mllib.tree.impl.{BaggedPoint, DecisionTreeMetadata, NodeIdCache,
   TimeTracker, TreePoint}
 import org.apache.spark.mllib.tree.impurity.Impurities