[SPARK-26370][SQL] Fix resolution of higher-order function for the sa…

…me identifier.

When using a higher-order function with the same variable name as the existing columns in `Filter` or something which uses `Analyzer.resolveExpressionBottomUp` during the resolution, e.g.,:

```scala
val df = Seq(
  (Seq(1, 9, 8, 7), 1, 2),
  (Seq(5, 9, 7), 2, 2),
  (Seq.empty, 3, 2),
  (null, 4, 2)
).toDF("i", "x", "d")

checkAnswer(df.filter("exists(i, x -> x % d == 0)"),
  Seq(Row(Seq(1, 9, 8, 7), 1, 2)))
checkAnswer(df.select("x").filter("exists(i, x -> x % d == 0)"),
  Seq(Row(1)))
```

the following exception happens:

```
java.lang.ClassCastException: org.apache.spark.sql.catalyst.expressions.BoundReference cannot be cast to org.apache.spark.sql.catalyst.expressions.NamedExpression
  at scala.collection.TraversableLike.$anonfun$map$1(TraversableLike.scala:237)
  at scala.collection.mutable.ResizableArray.foreach(ResizableArray.scala:62)
  at scala.collection.mutable.ResizableArray.foreach$(ResizableArray.scala:55)
  at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:49)
  at scala.collection.TraversableLike.map(TraversableLike.scala:237)
  at scala.collection.TraversableLike.map$(TraversableLike.scala:230)
  at scala.collection.AbstractTraversable.map(Traversable.scala:108)
  at org.apache.spark.sql.catalyst.expressions.HigherOrderFunction.$anonfun$functionsForEval$1(higherOrderFunctions.scala:147)
  at scala.collection.TraversableLike.$anonfun$map$1(TraversableLike.scala:237)
  at scala.collection.immutable.List.foreach(List.scala:392)
  at scala.collection.TraversableLike.map(TraversableLike.scala:237)
  at scala.collection.TraversableLike.map$(TraversableLike.scala:230)
  at scala.collection.immutable.List.map(List.scala:298)
  at org.apache.spark.sql.catalyst.expressions.HigherOrderFunction.functionsForEval(higherOrderFunctions.scala:145)
  at org.apache.spark.sql.catalyst.expressions.HigherOrderFunction.functionsForEval$(higherOrderFunctions.scala:145)
  at org.apache.spark.sql.catalyst.expressions.ArrayExists.functionsForEval$lzycompute(higherOrderFunctions.scala:369)
  at org.apache.spark.sql.catalyst.expressions.ArrayExists.functionsForEval(higherOrderFunctions.scala:369)
  at org.apache.spark.sql.catalyst.expressions.SimpleHigherOrderFunction.functionForEval(higherOrderFunctions.scala:176)
  at org.apache.spark.sql.catalyst.expressions.SimpleHigherOrderFunction.functionForEval$(higherOrderFunctions.scala:176)
  at org.apache.spark.sql.catalyst.expressions.ArrayExists.functionForEval(higherOrderFunctions.scala:369)
  at org.apache.spark.sql.catalyst.expressions.ArrayExists.nullSafeEval(higherOrderFunctions.scala:387)
  at org.apache.spark.sql.catalyst.expressions.SimpleHigherOrderFunction.eval(higherOrderFunctions.scala:190)
  at org.apache.spark.sql.catalyst.expressions.SimpleHigherOrderFunction.eval$(higherOrderFunctions.scala:185)
  at org.apache.spark.sql.catalyst.expressions.ArrayExists.eval(higherOrderFunctions.scala:369)
  at org.apache.spark.sql.catalyst.expressions.GeneratedClass$SpecificPredicate.eval(Unknown Source)
  at org.apache.spark.sql.execution.FilterExec.$anonfun$doExecute$3(basicPhysicalOperators.scala:216)
  at org.apache.spark.sql.execution.FilterExec.$anonfun$doExecute$3$adapted(basicPhysicalOperators.scala:215)

...
```

because the `UnresolvedAttribute`s in `LambdaFunction` are unexpectedly resolved by the rule.

This pr modified to use a placeholder `UnresolvedNamedLambdaVariable` to prevent unexpected resolution.

Added a test and modified some tests.

Closes #23320 from ueshin/issues/SPARK-26370/hof_resolution.

Authored-by: Takuya UESHIN <ueshin@databricks.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
(cherry picked from commit 3dda58a)
Signed-off-by: Wenchen Fan <wenchen@databricks.com>

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/higherOrderFunctions.scala

@@ -148,13 +148,14 @@ case class ResolveLambdaVariables(conf: SQLConf) extends Rule[LogicalPlan] {
       val lambdaMap = l.arguments.map(v => canonicalizer(v.name) -> v).toMap
       l.mapChildren(resolve(_, parentLambdaMap ++ lambdaMap))
 
-    case u @ UnresolvedAttribute(name +: nestedFields) =>
+    case u @ UnresolvedNamedLambdaVariable(name +: nestedFields) =>
       parentLambdaMap.get(canonicalizer(name)) match {
         case Some(lambda) =>
           nestedFields.foldLeft(lambda: Expression) { (expr, fieldName) =>
             ExtractValue(expr, Literal(fieldName), conf.resolver)
           }
-        case None => u
+        case None =>
+          UnresolvedAttribute(u.nameParts)
       }
 
     case _ =>

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

@@ -22,12 +22,34 @@ import java.util.concurrent.atomic.AtomicReference
 import scala.collection.mutable
 
 import org.apache.spark.sql.catalyst.InternalRow
-import org.apache.spark.sql.catalyst.analysis.{TypeCheckResult, TypeCoercion, UnresolvedAttribute}
+import org.apache.spark.sql.catalyst.analysis.{TypeCheckResult, TypeCoercion, UnresolvedAttribute, UnresolvedException}
 import org.apache.spark.sql.catalyst.expressions.codegen._
 import org.apache.spark.sql.catalyst.util._
 import org.apache.spark.sql.types._
 import org.apache.spark.unsafe.array.ByteArrayMethods
 
+/**
+ * A placeholder of lambda variables to prevent unexpected resolution of [[LambdaFunction]].
+ */
+case class UnresolvedNamedLambdaVariable(nameParts: Seq[String])
+  extends LeafExpression with NamedExpression with Unevaluable {
+
+  override def name: String =
+    nameParts.map(n => if (n.contains(".")) s"`$n`" else n).mkString(".")
+
+  override def exprId: ExprId = throw new UnresolvedException(this, "exprId")
+  override def dataType: DataType = throw new UnresolvedException(this, "dataType")
+  override def nullable: Boolean = throw new UnresolvedException(this, "nullable")
+  override def qualifier: Seq[String] = throw new UnresolvedException(this, "qualifier")
+  override def toAttribute: Attribute = throw new UnresolvedException(this, "toAttribute")
+  override def newInstance(): NamedExpression = throw new UnresolvedException(this, "newInstance")
+  override lazy val resolved = false
+
+  override def toString: String = s"lambda '$name"
+
+  override def sql: String = name
+}
+
 /**
  * A named lambda variable.
  */
@@ -79,7 +101,7 @@ case class LambdaFunction(
 
 object LambdaFunction {
   val identity: LambdaFunction = {
-    val id = UnresolvedAttribute.quoted("id")
+    val id = UnresolvedNamedLambdaVariable(Seq("id"))
     LambdaFunction(id, Seq(id))
   }
 }

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/parser/AstBuilder.scala

@@ -1336,9 +1336,12 @@ class AstBuilder(conf: SQLConf) extends SqlBaseBaseVisitor[AnyRef] with Logging
    */
   override def visitLambda(ctx: LambdaContext): Expression = withOrigin(ctx) {
     val arguments = ctx.IDENTIFIER().asScala.map { name =>
-      UnresolvedAttribute.quoted(name.getText)
+      UnresolvedNamedLambdaVariable(UnresolvedAttribute.quoted(name.getText).nameParts)
     }
-    LambdaFunction(expression(ctx.expression), arguments)
+    val function = expression(ctx.expression).transformUp {
+      case a: UnresolvedAttribute => UnresolvedNamedLambdaVariable(a.nameParts)
+    }
+    LambdaFunction(function, arguments)
   }
 
   /**

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/analysis/ResolveLambdaVariablesSuite.scala

@@ -49,19 +49,21 @@ class ResolveLambdaVariablesSuite extends PlanTest {
     comparePlans(Analyzer.execute(plan(e1)), plan(e2))
   }
 
+  private def lv(s: Symbol) = UnresolvedNamedLambdaVariable(Seq(s.name))
+
   test("resolution - no op") {
     checkExpression(key, key)
   }
 
   test("resolution - simple") {
-    val in = ArrayTransform(values1, LambdaFunction('x.attr + 1, 'x.attr :: Nil))
+    val in = ArrayTransform(values1, LambdaFunction(lv('x) + 1, lv('x) :: Nil))
     val out = ArrayTransform(values1, LambdaFunction(lvInt + 1, lvInt :: Nil))
     checkExpression(in, out)
   }
 
   test("resolution - nested") {
     val in = ArrayTransform(values2, LambdaFunction(
-      ArrayTransform('x.attr, LambdaFunction('x.attr + 1, 'x.attr :: Nil)), 'x.attr :: Nil))
+      ArrayTransform(lv('x), LambdaFunction(lv('x) + 1, lv('x) :: Nil)), lv('x) :: Nil))
     val out = ArrayTransform(values2, LambdaFunction(
       ArrayTransform(lvArray, LambdaFunction(lvInt + 1, lvInt :: Nil)), lvArray :: Nil))
     checkExpression(in, out)
@@ -75,14 +77,14 @@ class ResolveLambdaVariablesSuite extends PlanTest {
 
   test("fail - name collisions") {
     val p = plan(ArrayTransform(values1,
-      LambdaFunction('x.attr + 'X.attr, 'x.attr :: 'X.attr :: Nil)))
+      LambdaFunction(lv('x) + lv('X), lv('x) :: lv('X) :: Nil)))
     val msg = intercept[AnalysisException](Analyzer.execute(p)).getMessage
     assert(msg.contains("arguments should not have names that are semantically the same"))
   }
 
   test("fail - lambda arguments") {
     val p = plan(ArrayTransform(values1,
-      LambdaFunction('x.attr + 'y.attr + 'z.attr, 'x.attr :: 'y.attr :: 'z.attr :: Nil)))
+      LambdaFunction(lv('x) + lv('y) + lv('z), lv('x) :: lv('y) :: lv('z) :: Nil)))
     val msg = intercept[AnalysisException](Analyzer.execute(p)).getMessage
     assert(msg.contains("does not match the number of arguments expected"))
   }

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/parser/ExpressionParserSuite.scala

@@ -246,9 +246,11 @@ class ExpressionParserSuite extends PlanTest {
     intercept("foo(a x)", "extraneous input 'x'")
   }
 
+  private def lv(s: Symbol) = UnresolvedNamedLambdaVariable(Seq(s.name))
+
   test("lambda functions") {
-    assertEqual("x -> x + 1", LambdaFunction('x + 1, Seq('x.attr)))
-    assertEqual("(x, y) -> x + y", LambdaFunction('x + 'y, Seq('x.attr, 'y.attr)))
+    assertEqual("x -> x + 1", LambdaFunction(lv('x) + 1, Seq(lv('x))))
+    assertEqual("(x, y) -> x + y", LambdaFunction(lv('x) + lv('y), Seq(lv('x), lv('y))))
   }
 
   test("window function expressions") {

sql/core/src/test/scala/org/apache/spark/sql/DataFrameFunctionsSuite.scala

@@ -2486,6 +2486,26 @@ class DataFrameFunctionsSuite extends QueryTest with SharedSQLContext {
     }
     assert(ex.getMessage.contains("Cannot use null as map key"))
   }
+
+  test("SPARK-26370: Fix resolution of higher-order function for the same identifier") {
+    val df = Seq(
+      (Seq(1, 9, 8, 7), 1, 2),
+      (Seq(5, 9, 7), 2, 2),
+      (Seq.empty, 3, 2),
+      (null, 4, 2)
+    ).toDF("i", "x", "d")
+
+    checkAnswer(df.selectExpr("x", "exists(i, x -> x % d == 0)"),
+      Seq(
+        Row(1, true),
+        Row(2, false),
+        Row(3, false),
+        Row(4, null)))
+    checkAnswer(df.filter("exists(i, x -> x % d == 0)"),
+      Seq(Row(Seq(1, 9, 8, 7), 1, 2)))
+    checkAnswer(df.select("x").filter("exists(i, x -> x % d == 0)"),
+      Seq(Row(1)))
+  }
 }
 
 object DataFrameFunctionsSuite {