[GitHub] [arrow] wesm commented on a change in pull request #7108: PARQUET-1857: [C++] Do not fail to read unencrypted files with over 32767 row groups. Change some DCHECKs causing segfaults to throw exceptions

[GitBox <gi...@apache.org>]

wesm commented on a change in pull request #7108:
URL: https://github.com/apache/arrow/pull/7108#discussion_r420739547



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File path: cpp/src/parquet/arrow/reader_internal.h
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@@ -76,7 +76,8 @@ class FileColumnIterator {
       return nullptr;
     }
 
-    auto row_group_reader = reader_->RowGroup(row_groups_.front());
+    int row_group_index = row_groups_.front();
+    auto row_group_reader = reader_->RowGroup(row_group_index);

Review comment:
       Without this change I was unable to determine at which row group index the failure occurred in the debugger. I can revert it but it seems useful to be able to know 




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