From ef8f5db89f9531c3cb8f0b319504d2b5f407e653 Mon Sep 17 00:00:00 2001
From: Zhenxiao Luo <luoz@uber.com>
Date: Fri, 15 Jun 2018 18:03:42 -0700
Subject: [PATCH] Fix New Parquet Reader reading array<struct<type:string>>

---
 .../src/main/java/parquet/io/ColumnIOConverter.java |  7 +++++++
 .../hive/parquet/AbstractTestParquetReader.java     | 13 +++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/presto-hive/src/main/java/parquet/io/ColumnIOConverter.java b/presto-hive/src/main/java/parquet/io/ColumnIOConverter.java
index 1a7e34fd0bfa0..6f8a17df6744e 100644
--- a/presto-hive/src/main/java/parquet/io/ColumnIOConverter.java
+++ b/presto-hive/src/main/java/parquet/io/ColumnIOConverter.java
@@ -52,6 +52,13 @@ public static Optional<Field> constructField(Type type, ColumnIO columnIO)
         int repetitionLevel = columnIO.getRepetitionLevel();
         int definitionLevel = columnIO.getDefinitionLevel();
         if (ROW.equals(type.getTypeSignature().getBase())) {
+            if (columnIO instanceof PrimitiveColumnIO) {
+                // single element struct
+                PrimitiveColumnIO primitiveColumnIO = (PrimitiveColumnIO) columnIO;
+                RichColumnDescriptor column = new RichColumnDescriptor(primitiveColumnIO.getColumnDescriptor(), columnIO.getType().asPrimitiveType());
+                Optional<Field> field = Optional.of(new PrimitiveField(type.getTypeParameters().get(0), repetitionLevel, definitionLevel, required, column, primitiveColumnIO.getId()));
+                return Optional.of(new GroupField(type, repetitionLevel, definitionLevel, required, ImmutableList.of(field)));
+            }
             GroupColumnIO groupColumnIO = (GroupColumnIO) columnIO;
             List<Type> parameters = type.getTypeParameters();
             ImmutableList.Builder<Optional<Field>> fileldsBuilder = ImmutableList.builder();
diff --git a/presto-hive/src/test/java/com/facebook/presto/hive/parquet/AbstractTestParquetReader.java b/presto-hive/src/test/java/com/facebook/presto/hive/parquet/AbstractTestParquetReader.java
index 909816901c55a..3a3f0ca19d8be 100644
--- a/presto-hive/src/test/java/com/facebook/presto/hive/parquet/AbstractTestParquetReader.java
+++ b/presto-hive/src/test/java/com/facebook/presto/hive/parquet/AbstractTestParquetReader.java
@@ -185,6 +185,19 @@ public void testArrayOfStructs()
                 values, values, new ArrayType(structType));
     }
 
+    @Test
+    public void testArrayOfStructOfSingleElement()
+            throws Exception
+    {
+        Iterable<List> structs = createNullableTestStructs(transform(intsBetween(0, 31_234), Object::toString));
+        Iterable<List<List>> values = createTestArrays(structs);
+        List<String> structFieldNames = asList("stringField");
+        Type structType = RowType.from(asList(field("stringField", VARCHAR)));
+        tester.testRoundTrip(
+                getStandardListObjectInspector(getStandardStructObjectInspector(structFieldNames, asList(javaStringObjectInspector))),
+                values, values, new ArrayType(structType));
+    }
+
     @Test
     public void testCustomSchemaArrayOfStucts()
             throws Exception