Behavior of column value ByteBuffer returned from Thrift calls is surprising
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                 Key: CASSANDRA-1680
                 URL: https://issues.apache.org/jira/browse/CASSANDRA-1680
             Project: Cassandra
          Issue Type: Bug
    Affects Versions: 0.7 beta 2
            Reporter: Jim Ancona


The Thrift Column object has a public ByteBuffer value member. In order to 
safely use that member, you must first process it call TBaseHelper.rightSize(). 
The Thrift Column object does this when getValue() is called, but of course has 
no way to do so when the value ByteBuffer is accessed directly. The end result 
is that you get unexpected results when accessing the ByteBuffer's underlying 
byte array. I suppose that arguably users of thrift should understand 
ByteBuffer semantics well enough to avoid getting burned, but I think in 
practice this is unlikely. 

You can reproduce the problem with the following sequence of operations in 
cassandra-cli in the cassandra-0.7 branch:

[defa...@mykeyspace] create column family CF1 with comparator=UTF8Type
76ab2284-e2e1-11df-93c0-e700f669bcfc
[defa...@mykeyspace] set CF1[key][integer] = Integer(12345678987654321)
Value inserted.
[defa...@mykeyspace] get CF1[key][integer]
=> (column=integer, value=12345678987654321, timestamp=1288304422843000)
[defa...@mykeyspace] get CF1[key]         
=> (column=integer, 
value=-8104275257521291409654259134258589618690198366301968500366925384201062337700106679188936883799193604223363867889371831541230052432517523790062908835405316953744191265273683116032,
 timestamp=1288304422843000)
Returned 1 results.

Note that the first Get returns the value that was set, but the second returns 
a bogus value because it goes through a code path that uses the value 
ByteBuffer directly. I can supply a patch for cassandra-cli, but I wonder if 
there's something that can be done at the Thrift level to make it harder for 
this to occur.



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