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DataContractSerializer retains sign when deserializing -0

  • Article

DataContractSerializer and DataContractJsonSerializer previously discarded the sign when deserializing the input "-0" as a float or double. Both serializers have always done the right thing when given "-0.0" as an input, but with an input of "-0", the sign was lost. This behavior is both inconsistent and results in data loss. In addition, these serializers write a value of negative zero out as "-0" during serialization.

Previous behavior

Previously, the negative sign was lost when deserializing "-0" (but not "-0.0") as a float or double using DataContractSerializer.

New behavior

The negative sign is now preserved when deserializing "-0" as a float or double.

Version introduced

  • .NET 6.0.11 (servicing release)
  • .NET 7

Type of breaking change

This change can affect binary compatibility.

Reason for change

The previous behavior was inconsistent and resulted in data loss.

In most cases, no action is needed. If your code was affected by the bug, then this is a good change. Or, you've already worked around the bug in a way that's unlikely to be broken by this change.

Affected APIs