fix: [~] child dynamic accessor only for struct columns (issue #265) (#…

…269)
hablapps · Feb 3, 2023 · 1fd8884 · 1fd8884
1 parent a4cd92a
commit 1fd8884
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Showing 3 changed files with 19 additions and 19 deletions.
diff --git a/core/src/main/scala/doric/DoricColumn.scala b/core/src/main/scala/doric/DoricColumn.scala
@@ -7,12 +7,10 @@ import doric.syntax.ColGetters
 import doric.types.{LiteralSparkType, SparkType}
 
 import org.apache.spark.sql.{Column, Dataset}
-import org.apache.spark.sql.catalyst.CatalystTypeConverters
 import org.apache.spark.sql.catalyst.analysis.UnresolvedAttribute
-import org.apache.spark.sql.catalyst.expressions.Literal
 import org.apache.spark.sql.types.DataType
 
-sealed trait DoricColumn[T] extends DynamicFieldAccessor[T] {
+sealed trait DoricColumn[T] {
   val elem: Doric[Column]
 }
 

diff --git a/core/src/main/scala/doric/syntax/DStructs.scala b/core/src/main/scala/doric/syntax/DStructs.scala
@@ -32,7 +32,7 @@ private[syntax] trait DStructs {
   ) {
 
     /**
-      * Retreaves the child row of the Struct column
+      * Retrieves the child row of the Struct column
       *
       * @group Struct Type
       * @param subColumnName
@@ -85,10 +85,13 @@ private[syntax] trait DStructs {
         .mapK(toValidated)
         .toDC
     }
+
+    def child: DynamicFieldAccessor[T] = new DynamicFieldAccessor(col)
   }
 
-  trait DynamicFieldAccessor[T] extends Dynamic {
-    self: DoricColumn[T] =>
+  class DynamicFieldAccessor[T](dCol: DoricColumn[T])(implicit
+      st: SparkType.Custom[T, Row]
+  ) extends Dynamic {
 
     /**
       * Allows for accessing fields of struct columns using the syntax `rowcol.name[T]`.
@@ -101,13 +104,9 @@ private[syntax] trait DStructs {
       * @return The column which refers to the given field
       * @throws doric.sem.ColumnTypeError if the parent column is not a struct
       */
-
-    def selectDynamic[A](name: String)(implicit
-        location: Location,
-        st: SparkType[A],
-        w: T Is Row
-    ): DoricColumn[A] =
-      w.lift[DoricColumn].coerce(self).getChild[A](name)
+    def selectDynamic[A: SparkType](name: String)(implicit
+        location: Location
+    ): DoricColumn[A] = dCol.getChild[A](name)
   }
 
   @annotation.implicitNotFound(msg = "No field ${K} in record ${L}")

diff --git a/core/src/test/scala/doric/syntax/DynamicSpec.scala b/core/src/test/scala/doric/syntax/DynamicSpec.scala
@@ -16,26 +16,29 @@ class DynamicSpec extends DoricTestElements with EitherValues with Matchers {
   describe("Dynamic invocations") {
 
     it("can get values from sub-columns of `Row`` columns") {
-      df.validateColumnType(colStruct("user").name[String])
-      df.validateColumnType(colStruct("user").age[Int])
+      colStruct("user").child.name[String]
+      df.validateColumnType(colStruct("user").child.name[String])
+      df.validateColumnType(colStruct("user").child.age[Int])
     }
 
     it("can get values from sub-sub-columns") {
       List(((("1", 2.0), 2), true))
         .toDF()
-        .validateColumnType(colStruct("_1")._1[Row]._1[String])
+        .validateColumnType(colStruct("_1").child._1[Row].child._1[String])
     }
 
     it("can get values from the top-level row") {
       df.validateColumnType(row.user[Row])
-      df.validateColumnType(row.user[Row].age[Int])
+      df.validateColumnType(row.user[Row].child.age[Int])
       List(("1", 2, true)).toDF().validateColumnType(row._1[String])
-      List((("1", 2), true)).toDF().validateColumnType(row._1[Row]._2[Int])
+      List((("1", 2), true))
+        .toDF()
+        .validateColumnType(row._1[Row].child._2[Int])
     }
 
     if (minorScalaVersion >= 12)
       it("should not compile if the parent column is not a row") {
-        """val c: DoricColumn[String] = col[Int]("id").name[String]""" shouldNot compile
+        """val c: DoricColumn[String] = col[Int]("id").child.name[String]""" shouldNot compile
       }
   }
 }