From 6d156e41857206cd148366c1a73152755be0f071 Mon Sep 17 00:00:00 2001
From: Pramod <pramod@ahana.io>
Date: Fri, 9 Aug 2024 12:56:29 -0700
Subject: [PATCH] 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: https://github.com/facebookincubator/velox/pull/10687

Reviewed By: Yuhta

Differential Revision: D61032300

Pulled By: xiaoxmeng

fbshipit-source-id: 38520b69cf575f0a7acc2184963573b432b76a85
---
 velox/dwio/parquet/reader/ParquetReader.cpp           | 5 ++++-
 velox/dwio/parquet/tests/reader/ParquetReaderTest.cpp | 2 ++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/velox/dwio/parquet/reader/ParquetReader.cpp b/velox/dwio/parquet/reader/ParquetReader.cpp
index 28170d235ff8..635366f19f13 100644
--- a/velox/dwio/parquet/reader/ParquetReader.cpp
+++ b/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(
diff --git a/velox/dwio/parquet/tests/reader/ParquetReaderTest.cpp b/velox/dwio/parquet/tests/reader/ParquetReaderTest.cpp
index 743f14682627..e46dfadfa1ef 100644
--- a/velox/dwio/parquet/tests/reader/ParquetReaderTest.cpp
+++ b/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);