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CASSANDRA-21505: CAS EQ/NEQ incorrectly distinguishes null from meaningless empty bytes for fixed-length types due to missing sanitization #5010

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CASSANDRA-21505: CAS EQ/NEQ incorrectly distinguishes null from meaningless empty bytes for fixed-length types due to missing sanitization #5010

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c8592c2
added isEmptyValueMeaningless support for LWT/CAS
minal-kyada Aug 10, 2026
d3317e2
harry model fix for CAS/LWT null/empty bytes comparisons
minal-kyada Aug 14, 2026
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4 changes: 3 additions & 1 deletion test/harry/main/org/apache/cassandra/harry/model/ASTSingleTableModel.java
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Original file line number Diff line number Diff line change
Expand Up @@ -1016,7 +1016,9 @@ else if (o instanceof SelectResult)
if (result.rows.length == 0)
return null;
ByteBuffer bb = result.rows[0][result.columns.indexOf(symbol)];
if (bb != null && symbol.type().isNull(bb))
// isEmptyValueMeaningless types store empty bytes as a distinct value from null;
// preserve it for CAS raw-byte comparison
if (bb != null && symbol.type().isNull(bb) && !symbol.type().isEmptyValueMeaningless())

@dcapwell dcapwell Aug 14, 2026

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this patch doesn't really make sense to me.

CAS IF with equality operators are the only place we need to special case where byte[0] != null, as the rest of the code (which goes through this code path) require byte[0] == null (we are only talking about meaningless emptyness).

So to fix CAS IF we need to break the rest of the CQL surface?

bb = null;
return bb;
}
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