[GitHub] [arrow] felipecrv opened a new issue, #36776: [C++] array_nested.cc: CleanListOffsets() assumes offsets.offset() is always 0

["felipecrv (via GitHub)" <gi...@apache.org>]

felipecrv opened a new issue, #36776:
URL: https://github.com/apache/arrow/issues/36776

   ### Describe the bug, including details regarding any error messages, version, and platform.
   
   `CleanListOffsets` (code below) copies the validity buffer slice starting from 0, but that can lead to copying the wrong bits when `offsets.offset()` is greater than 0.
   
   ```cpp
       ARROW_ASSIGN_OR_RAISE(
           auto clean_validity_buffer,
           offsets.null_bitmap()->CopySlice(0, bit_util::BytesForBits(num_offsets - 1)));
   ```
   
   https://github.com/apache/arrow/blob/3f0b62038d7ddac090db316722f5a1695e85701b/cpp/src/arrow/array/array_nested.cc#L55-L99
   
   The fix is simple: use `CopyBitmap` which knows how to handle offsets at the bit granularity.
   
   ### Component(s)
   
   C++


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[GitHub] [arrow] pitrou closed issue #36776: [C++] array_nested.cc: CleanListOffsets() assumes offsets.offset() is always 0

["pitrou (via GitHub)" <gi...@apache.org>]

pitrou closed issue #36776: [C++] array_nested.cc: CleanListOffsets() assumes offsets.offset() is always 0
URL: https://github.com/apache/arrow/issues/36776


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