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Avro >> mail # user >> Possible bug: byteBuffer limit not respected when copying


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Possible bug: byteBuffer limit not respected when copying
Hi,

In org.apache.avro.generic.GenericData.deepCopy - the code for copying a
ByteBuffer is
        ByteBuffer byteBufferValue = (ByteBuffer) value;
        byte[] bytesCopy = new byte[byteBufferValue.capacity()];
        byteBufferValue.rewind();
        byteBufferValue.get(bytesCopy);
        byteBufferValue.rewind();
        return ByteBuffer.wrap(bytesCopy);

I think this is problematic because it will cause an UnderFlow exception to
be thrown if the ByteBuffer limit is less than the capacity of the byte
buffer.

My use case is as follows. I have ByteBuffer's backed by large arrays so I
can avoid resizing the array every time I write data. So limit < capacity.
When the data is written, or copied
I think avro should respect this. When data is serialized, avro should
automatically use the minimum number of bytes.
When an object is copied, I think it makes sense to preserve the capacity
of the underlying buffer as opposed to compacting it.

So I think the code could be fixed by replacing get with
byteBufferValue.get(bytesCopy, 0 , byteBufferValue.limit());

Before I file a bug is there anything I'm missing?

J