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Type:
Improvement
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Resolution: Unresolved
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Priority:
Major - P3
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None
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Affects Version/s: 2.11.6
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Component/s: Serialization
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Labels:None
The MongoDB C# Driver does not support System.Collections.Immutable out of the box yet. For example, when a ImmutableList<T> is deserialized, the following exception is thrown:
An error occurred while deserializing the XY property of class XY: Type 'System.Collections.Immutable.ImmutableList`1[[...]]' does not have a suitable constructor or Add method.'
It is possible, yet cumbersome, to add custom serializers for supporting them.
For example, for ImmutableList<T>:
public class ImmutableListSerializer<TValue> : EnumerableInterfaceImplementerSerializerBase<ImmutableList<TValue>, TValue> { protected override object CreateAccumulator() => ImmutableList.CreateBuilder<TValue>(); protected override ImmutableList<TValue> FinalizeResult(object accumulator) => ((ImmutableList<TValue>.Builder)accumulator).ToImmutable(); }
Since immutable collections are a native part of the .NET Runtime and will get increasing attention with the new immutable `record`s possible in C# 9, it would be very useful to support them out-of-the-box.
More example code, yet outdated, can be found in this github project: https://github.com/marcpiechura/MongoDB.Immutable