MsgPack002.md

MsgPack002 Avoid using a mutable static value for MessagePackSerializerOptions

Providing a static value for MessagePackSerializerOptions from a mutable member can lead to malfunction when that member is mutated by another party.

Examples of patterns that are flagged by this analyzer

MessagePackSerializer.Serialize(obj, MessagePackSerializer.DefaultOptions);

or consuming your own static mutable member:

public class Foo
{
    public static MessagePackSerializerOptions MyOptions = MessagePackSerializerOptions.Standard;

    void Bar()
    {
        MessagePackSerializer.Serialize(obj, MyOptions); // diagnostic flagged here
    }
}

or consuming a static mutable member from MessagePack to define your own:

public class Foo
{
    public static readonly MessagePackSerializerOptions MyOptions = MessagePackSerializer.DefaultOptions;

Solution

Use a MessagePackSerializerOptions value that comes from an immutable static property or field, or any instance member or local variable.

MessagePackSerializer.Serialize(obj, MessagePackSerializerOptions.Standard);

or mark your own static field/property as readonly:

public class Foo
{
    public static readonly MessagePackSerializerOptions MyOptions = MessagePackSerializerOptions.Standard;

    void Bar()
    {
        MessagePackSerializer.Serialize(obj, MyOptions);
    }
}