PolymorphicObjectConverter throws InvalidOperationException for decimals

[chris-sargood]

Hi,

We're getting the following exception thrown:

Exception Details

    ---> System.InvalidOperationException: The requested operation requires an element of type 'Object', but the target element has type 'Number'.
         at System.Text.Json.ThrowHelper.ThrowJsonElementWrongTypeException(JsonTokenType expectedType, JsonTokenType actualType)
         at System.Text.Json.JsonElement.EnumerateObject()
         at Elsa.Workflows.Core.Serialization.Converters.PolymorphicObjectConverter.Write(Utf8JsonWriter writer, Object value, JsonSerializerOptions options)

Version

Elsa V3.0.0-preview.906

Steps to reproduce

Run a workflow that has an Expando object variable. Then assign a Decimal to the expando. Run the workflow.

This workflow demonstrates the issue:

public class IffyWorkflow : WorkflowBase
{
    protected override void Build(IWorkflowBuilder builder)
    {
        var document = builder.WithVariable<ExpandoObject>();
        builder.Root = new Sequence
        {
            Activities =
            {
                new Inline(context =>
                {
                    dynamic boom = new ExpandoObject();
                    boom.Ok = "456";
                    boom.AlsoOk = 456;
                    boom.NotOk = 456m;
                    context.Set(document,boom);
                }),
                new Finish()
            }
        };
    }
}

Result

Execution of the JsonWorkflowStateSerializer will eventually cause the above exception to be thrown and the WorkflowInstance table wont be updated.

Cause

Decimals aren't Primitives. When Elsa.Workflows.Core.Serialization.Converters.PolymorphicObjectConverter tests using if (type.IsPrimitive || value is string or DateTimeOffset or DateTime or DateOnly or TimeOnly or JsonElement or Guid or TimeSpan or Uri or Version or Enum) false is returned.
Execution will continue to foreach (var property in jsonElement.EnumerateObject().Where(property => !property.NameEquals(TypePropertyName))) which causes the exception as the value isn't an Object either.

[sfmskywalker]

Thanks for the great bug report - I was able to reproduce this with the latest version 👍🏻