[GitHub] [arrow-rs] tustvold opened a new issue, #1824: value_offsets Returns Invalid Slice For Empty Offsets Buffer

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

tustvold opened a new issue, #1824:
URL: https://github.com/apache/arrow-rs/issues/1824

   **Describe the bug**
   
   I don't know if this was a change or it has always been this way, but we permit zero-length ListArray to have no offsets. In #1620 we explicitly decided against enforcing a single value.
   
   Unfortunately the logic for value_offsets, duplicated in ListArray, StringArray, BinaryArray, etc...
   
   ```
   unsafe {
       std::slice::from_raw_parts(
           self.value_offsets.as_ptr().add(self.data.offset()),
           self.len() + 1,
       )
   }
   ```
   
   Does not take this into account
   
   **To Reproduce**
   
   ```
   #[test]
   fn test_string_array_empty_offsets() {
       let data = ArrayDataBuilder::new(DataType::Utf8)
           .len(0)
           .add_buffer(Buffer::from([]))
           .add_buffer(Buffer::from([]))
           .build()
           .unwrap();
       let array = GenericStringArray::<i32>::from(data);
       assert_eq!(array.value_offsets().len(), 0); // FAILS with 1 != 0
   }
   ```
   
   **Expected behavior**
   
   Given the decision to support empty offsets, I think we should always return an empty slice for zero length array types, so that the behaviour is consistent.
   
   **Additional context**
   
   Discovered whilst working on #1811, so already getting returns from that investment :grin: 
   


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[GitHub] [arrow-rs] tustvold closed issue #1824: Invalid Value Offsets Slice For Empty Variable Length Arrays

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

tustvold closed issue #1824: Invalid Value Offsets Slice For Empty Variable Length Arrays
URL: https://github.com/apache/arrow-rs/issues/1824


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