[SPARK-3365][SQL]Wrong schema generated for List type

This PR fix the issue SPARK-3365.
The reason is Spark generated wrong schema for the type `List` in `ScalaReflection.scala`
for example:

the generated schema for type `Seq[String]` is:
```
{"name":"x","type":{"type":"array","elementType":"string","containsNull":true},"nullable":true,"metadata":{}}`
```

the generated schema for type `List[String]` is:
```
{"name":"x","type":{"type":"struct","fields":[]},"nullable":true,"metadata":{}}`
```

Author: tianyi <tianyi.asiainfo@gmail.com>

Closes #4581 from tianyi/SPARK-3365 and squashes the following commits:

a097e86 [tianyi] change the order of resolution in ScalaReflection.scala

2 files changed, 20 insertions, 15 deletions

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaReflection.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaReflection.scala
index 5d9c331ca5..11fd443733 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaReflection.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaReflection.scala
@@ -122,6 +122,21 @@ trait ScalaReflection {
       case t if t <:< typeOf[Option[_]] =>
         val TypeRef(_, _, Seq(optType)) = t
         Schema(schemaFor(optType).dataType, nullable = true)
+      // Need to decide if we actually need a special type here.
+      case t if t <:< typeOf[Array[Byte]] => Schema(BinaryType, nullable = true)
+      case t if t <:< typeOf[Array[_]] =>
+        val TypeRef(_, _, Seq(elementType)) = t
+        val Schema(dataType, nullable) = schemaFor(elementType)
+        Schema(ArrayType(dataType, containsNull = nullable), nullable = true)
+      case t if t <:< typeOf[Seq[_]] =>
+        val TypeRef(_, _, Seq(elementType)) = t
+        val Schema(dataType, nullable) = schemaFor(elementType)
+        Schema(ArrayType(dataType, containsNull = nullable), nullable = true)
+      case t if t <:< typeOf[Map[_, _]] =>
+        val TypeRef(_, _, Seq(keyType, valueType)) = t
+        val Schema(valueDataType, valueNullable) = schemaFor(valueType)
+        Schema(MapType(schemaFor(keyType).dataType,
+          valueDataType, valueContainsNull = valueNullable), nullable = true)
       case t if t <:< typeOf[Product] =>
         val formalTypeArgs = t.typeSymbol.asClass.typeParams
         val TypeRef(_, _, actualTypeArgs) = t
@@ -144,21 +159,6 @@ trait ScalaReflection {
               schemaFor(p.typeSignature.substituteTypes(formalTypeArgs, actualTypeArgs))
             StructField(p.name.toString, dataType, nullable)
           }), nullable = true)
-      // Need to decide if we actually need a special type here.
-      case t if t <:< typeOf[Array[Byte]] => Schema(BinaryType, nullable = true)
-      case t if t <:< typeOf[Array[_]] =>
-        val TypeRef(_, _, Seq(elementType)) = t
-        val Schema(dataType, nullable) = schemaFor(elementType)
-        Schema(ArrayType(dataType, containsNull = nullable), nullable = true)
-      case t if t <:< typeOf[Seq[_]] =>
-        val TypeRef(_, _, Seq(elementType)) = t
-        val Schema(dataType, nullable) = schemaFor(elementType)
-        Schema(ArrayType(dataType, containsNull = nullable), nullable = true)
-      case t if t <:< typeOf[Map[_, _]] =>
-        val TypeRef(_, _, Seq(keyType, valueType)) = t
-        val Schema(valueDataType, valueNullable) = schemaFor(valueType)
-        Schema(MapType(schemaFor(keyType).dataType,
-          valueDataType, valueContainsNull = valueNullable), nullable = true)
       case t if t <:< typeOf[String] => Schema(StringType, nullable = true)
       case t if t <:< typeOf[Timestamp] => Schema(TimestampType, nullable = true)
       case t if t <:< typeOf[java.sql.Date] => Schema(DateType, nullable = true)
diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/ScalaReflectionSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/ScalaReflectionSuite.scala
index d0f547d187..eee00e3f7e 100644
--- a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/ScalaReflectionSuite.scala
+++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/ScalaReflectionSuite.scala
@@ -61,6 +61,7 @@ case class OptionalData(
 case class ComplexData(
     arrayField: Seq[Int],
     arrayField1: Array[Int],
+    arrayField2: List[Int],
     arrayFieldContainsNull: Seq[java.lang.Integer],
     mapField: Map[Int, Long],
     mapFieldValueContainsNull: Map[Int, java.lang.Long],
@@ -138,6 +139,10 @@ class ScalaReflectionSuite extends FunSuite {
           ArrayType(IntegerType, containsNull = false),
           nullable = true),
         StructField(
+          "arrayField2",
+          ArrayType(IntegerType, containsNull = false),
+          nullable = true),
+        StructField(
           "arrayFieldContainsNull",
           ArrayType(IntegerType, containsNull = true),
           nullable = true),