Failed to retrieve memory block with reference e5096ef278eb4cbeb42fc42ac22a0f15

[franjosuerr]

Discussed in #6167

^{Originally posted by franjosuerr November 29, 2024}
at Elsa.Expressions.Models.ExpressionExecutionContext.GetBlock(MemoryBlockReference blockReference) at Elsa.Expressions.Models.ExpressionExecutionContext.Get(MemoryBlockReference blockReference) at Elsa.Expressions.Models.MemoryBlockReference.Get(ExpressionExecutionContext context) at Elsa.Workflows.Expressions.VariableExpressionHandler.EvaluateAsync(Expression expression, Type returnType, ExpressionExecutionContext context, ExpressionEvaluatorOptions options) at Elsa.Expressions.Services.ExpressionEvaluator.EvaluateAsync(Expression expression, Type returnType, ExpressionExecutionContext context, ExpressionEvaluatorOptions options) at Elsa.Extensions.ActivityExecutionContextExtensions.EvaluateInputPropertyAsync(ActivityExecutionContext context, ActivityDescriptor activityDescriptor, InputDescriptor inputDescriptor) at Elsa.Extensions.ActivityExecutionContextExtensions.EvaluateInputPropertiesAsync(ActivityExecutionContext context) at Elsa.Workflows.Middleware.Activities.DefaultActivityInvokerMiddleware.EvaluateInputPropertiesAsync(ActivityExecutionContext context) at Elsa.Workflows.Middleware.Activities.DefaultActivityInvokerMiddleware.InvokeAsync(ActivityExecutionContext context) at Elsa.Workflows.Middleware.Activities.NotificationPublishingMiddleware.InvokeAsync(ActivityExecutionContext context) at Elsa.Workflows.Middleware.Activities.ExecutionLogMiddleware.InvokeAsync(ActivityExecutionContext context) at Elsa.Workflows.Middleware.Activities.ExceptionHandlingMiddleware.InvokeAsync(ActivityExecutionContext context)

When I run a flowchart workflow where I pass a numeric value to an activity as a parameter, I get this error. I fix it by removing the default constructor in this activity, but when I remove it, I get a JSON exception. According to the documentation, the default constructor is necessary, but it blocks the execution of the activities.

[franjosuerr]

thanks to @sfmskywalker i solved it
He recommended me:
1-On the Activity class, make sure it has a default constructor that is decorated with the [JsonConstructor] attribute.
2-In the workflow class, make sure that the variables are scoped to the workflow. builder.WithVariable is a helper for that.