Fix childName to consider ReaderOption fileColumnNamesReadAsLowerCase (…

…#10687)

Summary:
Converts `childName` to lowercase if hive config `isFileColumnNamesReadAsLowerCase`
is enabled.

cc: yingsu00 aditi-pandit

Pull Request resolved: #10687

Reviewed By: Yuhta

Differential Revision: D61032300

Pulled By: xiaoxmeng

fbshipit-source-id: 38520b69cf575f0a7acc2184963573b432b76a85

velox/dwio/parquet/reader/ParquetReader.cpp

@@ -280,7 +280,10 @@ std::unique_ptr<ParquetTypeWithId> ReaderBase::getParquetColumnInfo(
     auto curSchemaIdx = schemaIdx;
     for (int32_t i = 0; i < schemaElement.num_children; i++) {
       ++schemaIdx;
-      auto& childName = schema[schemaIdx].name;
+      auto childName = schema[schemaIdx].name;
+      if (isFileColumnNamesReadAsLowerCase()) {
+        folly::toLowerAscii(childName);
+      }
       auto childRequestedType =
           requestedType ? requestedType->asRow().findChild(childName) : nullptr;
       auto child = getParquetColumnInfo(

velox/dwio/parquet/tests/reader/ParquetReaderTest.cpp

@@ -304,6 +304,8 @@ TEST_F(ParquetReaderTest, parseReadAsLowerCase) {
   const std::string upper(getExampleFilePath("upper.parquet"));
 
   dwio::common::ReaderOptions readerOptions{leafPool_.get()};
+  auto outputRowType = ROW({"a", "b"}, {BIGINT(), BIGINT()});
+  readerOptions.setFileSchema(outputRowType);
   readerOptions.setFileColumnNamesReadAsLowerCase(true);
   auto reader = createReader(upper, readerOptions);
   EXPECT_EQ(reader->numberOfRows(), 2ULL);