Fix a serialization/casting issue in WorkflowExecutionContext.SetLastResult

src/core/Elsa.Abstractions/Services/Models/WorkflowExecutionContext.cs

@@ -86,8 +86,8 @@ namespace Elsa.Services.Models
         public Task<T> EvaluateAsync<T>(IWorkflowExpression<T> expression, CancellationToken cancellationToken) =>
             ExpressionEvaluator.EvaluateAsync(expression, this, cancellationToken);
 
-        public void SetLastResult(object value) => CurrentScope.LastResult = (JValue)value;
-        public void SetLastResult(JValue value) => CurrentScope.LastResult = value;
+        public void SetLastResult(object value) => SetLastResult(JToken.FromObject(value));
+        public void SetLastResult(JToken value) => CurrentScope.LastResult = value;
 
         public void Start()
         {

src/persistence/Elsa.Persistence.DocumentDb/Elsa.Persistence.DocumentDb.csproj

@@ -3,7 +3,6 @@
     <PropertyGroup>
         <TargetFramework>netstandard2.0</TargetFramework>
         <LangVersion>8.0</LangVersion>
-        <Nullable>enable</Nullable>
         <PackageVersion>1.0.0</PackageVersion>
         <Authors>Elsa Contributors</Authors>
         <Description>

src/samples/Sample17/Activities/CreatePerson.cs

@@ -38,9 +38,9 @@ namespace Sample17.Activities
             var age = await expressionEvaluator.EvaluateAsync(AgeExpression, context, cancellationToken);
             var person = new Person { FullName = name, Age = age };
 
-            Output["Person"] = person;
-            Output["FullName"] = person.FullName;
-            Output["Age"] = person.Age;
+            Output.SetVariable("Person", person);
+            Output.SetVariable("FullName", person.FullName);
+            Output.SetVariable("Age", person.Age);
             
             return Done();
         }