Address hvanhovell's comments

Blame Rev:

Author: janewangfb

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

@@ -90,24 +90,19 @@ case class UnresolvedTableValuedFunction(
  * @param table an optional table that should be the target of the expansion.  If omitted all
  *              tables' columns are produced.
  */
-case class UnresolvedRegex(expr: String, table: Option[String]) extends Star with Unevaluable {
+case class UnresolvedRegex(regexPattern: String, table: Option[String])
+  extends Star with Unevaluable {
   override def expand(input: LogicalPlan, resolver: Resolver): Seq[NamedExpression] = {
-    val expandedAttributes: Seq[Attribute] = table match {
+    table match {
       // If there is no table specified, use all input attributes that match expr
-      case None => input.output.filter(_.name.matches(expr))
+      case None => input.output.filter(_.name.matches(regexPattern))
       // If there is a table, pick out attributes that are part of this table that match expr
-      case Some(t) => input.output.filter(_.qualifier.filter(resolver(_, t)).nonEmpty)
-        .filter(_.name.matches(expr))
-    }
-
-    expandedAttributes.zip(input.output).map {
-      case (n: NamedExpression, _) => n
-      case (e, originalAttribute) =>
-        Alias(e, originalAttribute.name)()
+      case Some(t) => input.output.filter(_.qualifier.exists(resolver(_, t)))
+        .filter(_.name.matches(regexPattern))
     }
   }
 
-  override def toString: String = table.map(_ + ".").getOrElse("") + expr
+  override def toString: String = table.map(_ + ".").getOrElse("") + regexPattern
 }
 
 /**

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

@@ -1239,18 +1239,12 @@ class AstBuilder(conf: SQLConf) extends SqlBaseBaseVisitor[AnyRef] with Logging
     val attr = ctx.fieldName.getText
     expression(ctx.base) match {
       case unresolved_attr @ UnresolvedAttribute(nameParts) =>
-        if (conf.supportQuotedIdentifiers) {
-          val escapedIdentifier = "`(.+)`".r
-          val ret = Option(ctx.fieldName.getStart).map(_.getText match {
-            case r@escapedIdentifier(i) =>
-              UnresolvedRegex(i, Some(unresolved_attr.name))
-            case _ =>
-              UnresolvedAttribute(nameParts :+ attr)
-          })
-          return ret.get
+        matchEscapedIdentifier(ctx.fieldName.getStart.getText) match {
+          case Some(i) if conf.supportQuotedIdentifiers =>
+            UnresolvedRegex(i, Some(unresolved_attr.name))
+          case _ =>
+            UnresolvedAttribute(nameParts :+ attr)
         }
-
-        UnresolvedAttribute(nameParts :+ attr)
       case e =>
         UnresolvedExtractValue(e, Literal(attr))
     }
@@ -1261,19 +1255,12 @@ class AstBuilder(conf: SQLConf) extends SqlBaseBaseVisitor[AnyRef] with Logging
    * quoted in ``
    */
   override def visitColumnReference(ctx: ColumnReferenceContext): Expression = withOrigin(ctx) {
-    if (conf.supportQuotedIdentifiers) {
-      val escapedIdentifier = "`(.+)`".r
-      val ret = Option(ctx.getStart).map(_.getText match {
-        case r @ escapedIdentifier(i) =>
-          UnresolvedRegex(i, None)
-        case _ =>
-          UnresolvedAttribute.quoted(ctx.getText)
-      })
-
-      return ret.get
+    matchEscapedIdentifier(ctx.getStart.getText) match {
+      case Some(i) if conf.supportQuotedIdentifiers =>
+        UnresolvedRegex(i, None)
+      case _ =>
+        UnresolvedAttribute.quoted(ctx.getText)
     }
-
-    UnresolvedAttribute.quoted(ctx.getText)
   }
 
   /**

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

@@ -177,6 +177,18 @@ object ParserUtils {
     sb.toString()
   }
 
+  val escapedIdentifier = "`(.+)`".r
+
+  /**
+   * Return the substring extracted using regex
+   */
+  def matchEscapedIdentifier(b: String): Option[String] = {
+    b match {
+      case escapedIdentifier(i) => Some(i)
+      case _ => None
+    }
+  }
+
   /** Some syntactic sugar which makes it easier to work with optional clauses for LogicalPlans. */
   implicit class EnhancedLogicalPlan(val plan: LogicalPlan) extends AnyVal {
     /**