Remove multiple execution scopes (#427)

src/activities/Elsa.Activities.ControlFlow/Activities/ForEach.cs

@@ -55,19 +55,13 @@ protected override async Task<ActivityExecutionResult> OnExecuteAsync(
 
             if (index >= collection.Count)
             {
-                context.EndScope();
                 CurrentIndex = 0;
                 return Done();
             }
 
             var value = collection[index];
             CurrentIndex++;
 
-            if (index == 0)
-            {
-                context.BeginScope();
-            }
-
             context.CurrentScope.SetVariable(IteratorName, value);
 
             return Outcome(OutcomeNames.Iterate);

src/activities/Elsa.Activities.ControlFlow/Activities/While.cs

@@ -39,14 +39,10 @@ protected override async Task<ActivityExecutionResult> OnExecuteAsync(
         {
             var loop = await expressionEvaluator.EvaluateAsync(ConditionExpression, context, cancellationToken);
 
-            if (HasStarted)
-                context.EndScope();
-
             if (loop)
             {
                 HasStarted = true;
-
-                context.BeginScope();
+
                 return Outcome(OutcomeNames.Iterate);
             }
 

src/core/Elsa.Abstractions/Models/WorkflowInstance.cs

@@ -16,7 +16,7 @@ public class WorkflowInstance
         public Instant? FaultedAt { get; set; }
         public Instant? AbortedAt { get; set; }
         public IDictionary<string, ActivityInstance> Activities { get; set; } = new Dictionary<string, ActivityInstance>();
-        public Stack<WorkflowExecutionScope> Scopes { get; set; }
+        public WorkflowExecutionScope Scope { get; set; }
         public Variables Input { get; set; }
         public HashSet<BlockingActivity> BlockingActivities { get; set; }
         public ICollection<LogEntry> ExecutionLog { get; set; }

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

@@ -28,11 +28,9 @@ public Workflow(
             Input = new Variables(input ?? Variables.Empty);
         }
 
-
-
         public Workflow()
         {
-            Scopes = new Stack<WorkflowExecutionScope>(new[] { new WorkflowExecutionScope() });
+            Scope = new WorkflowExecutionScope();
             BlockingActivities = new HashSet<IActivity>();
             ExecutionLog = new List<LogEntry>();
         }
@@ -48,7 +46,7 @@ public Workflow()
         public Instant? AbortedAt { get; set; }
         public ICollection<IActivity> Activities { get; } = new List<IActivity>();
         public IList<Connection> Connections { get; } = new List<Connection>();
-        public Stack<WorkflowExecutionScope> Scopes { get; set; }
+        public WorkflowExecutionScope Scope { get; set; }
         public HashSet<IActivity> BlockingActivities { get; set; }
         public IList<LogEntry> ExecutionLog { get; set; }
         public WorkflowFault Fault { get; set; }
@@ -72,7 +70,7 @@ public WorkflowInstance ToInstance()
                 FaultedAt = FaultedAt,
                 AbortedAt = AbortedAt,
                 Activities = activities,
-                Scopes = new Stack<WorkflowExecutionScope>(Scopes),
+                Scope = Scope,
 
                 BlockingActivities = new HashSet<BlockingActivity>(
                     BlockingActivities.Select(x => new BlockingActivity(x.Id, x.Type)),
@@ -100,12 +98,11 @@ public void Initialize(WorkflowInstance instance)
             FaultedAt = instance.FaultedAt;
             AbortedAt = instance.AbortedAt;
             ExecutionLog = instance.ExecutionLog.ToList();
+            Scope = instance.Scope;
 
             BlockingActivities =
                 new HashSet<IActivity>(instance.BlockingActivities.Select(x => activityLookup[x.ActivityId]));
-
-            Scopes = new Stack<WorkflowExecutionScope>(instance.Scopes);
-
+
             foreach (var activity in Activities)
             {
                 activity.State = new JObject(instance.Activities[activity.Id].State);

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

@@ -35,7 +35,7 @@ public WorkflowExecutionContext(Workflow workflowInstance, IClock clock, IServic
         public IEnumerable<IActivity> ScheduledActivities => scheduledActivities;
         public bool IsFirstPass { get; set; }
         public LogEntry CurrentLogEntry => Workflow.ExecutionLog.LastOrDefault();
-        public WorkflowExecutionScope CurrentScope => Workflow.Scopes.Peek();
+        public WorkflowExecutionScope CurrentScope => Workflow.Scope;
         public Variables TransientState { get; } = new Variables();
         public IActivity CurrentActivity { get; private set; }
         public void ScheduleActivities(params IActivity[] activities) => ScheduleActivities((IEnumerable<IActivity>)activities);
@@ -48,9 +48,6 @@ public void ScheduleActivities(IEnumerable<IActivity> activities)
             }
         }
 
-        public void BeginScope() => Workflow.Scopes.Push(new WorkflowExecutionScope());
-        public void EndScope() => Workflow.Scopes.Pop();
-
         public void ScheduleActivity(IActivity activity)
         {
             scheduledActivities.Push(activity);
@@ -62,21 +59,9 @@ public void ScheduleActivity(IActivity activity)
         public IActivity PopScheduledHaltingActivity() => scheduledHaltingActivities.Pop();
         public IWorkflowExpressionEvaluator ExpressionEvaluator { get; }
 
-        public void SetVariable(string name, object value)
-        {
-            // Get the first scope (starting from the oldest one) containing the variable (existing variable). Otherwise use the current scope (new variable declaration)
-            var scope = Workflow.Scopes.Reverse().FirstOrDefault(x => x.Variables.ContainsKey(name)) ?? CurrentScope;
-            scope.SetVariable(name, value);
-        }
-
+        public void SetVariable(string name, object value) => CurrentScope.SetVariable(name, value);
         public T GetVariable<T>(string name) => (T) GetVariable(name);
-
-        public object GetVariable(string name)
-        {
-            // Get the first scope (starting from the newest one) containing the variable.
-            var scope = Workflow.Scopes.FirstOrDefault(x => x.Variables.ContainsKey(name)) ?? CurrentScope;
-            return scope.GetVariable(name);
-        }
+        public object GetVariable(string name) => CurrentScope.GetVariable(name);
 
         public Task<T> EvaluateAsync<T>(IWorkflowExpression<T> expression, CancellationToken cancellationToken) =>
             ExpressionEvaluator.EvaluateAsync(expression, this, cancellationToken);
@@ -123,9 +108,6 @@ public void Abort()
             Workflow.Status = WorkflowStatus.Aborted;
         }
 
-        public Variables GetVariables() => Workflow.Scopes
-            .Reverse()
-            .Select(x => x.Variables)
-            .Aggregate(Variables.Empty, (x, y) => new Variables(x.Union(y)));
+        public Variables GetVariables() => CurrentScope.Variables;
     }
 }

src/persistence/Elsa.Persistence.MongoDb/Extensions/ServiceCollectionExtensions.cs

@@ -22,7 +22,7 @@ string connectionStringName
         )
         {
             NodaTimeSerializers.Register();
-            RegisterEnumAsStringConvention();
+            RegisterConventions();
             BsonSerializer.RegisterSerializer(new JObjectSerializer());
             BsonSerializer.RegisterSerializer(new WorkflowExecutionScopeSerializer());
 
@@ -90,11 +90,17 @@ private static IMongoClient CreateDbClient(IConfiguration configuration, string
             return new MongoClient(connectionString);
         }
 
-        private static void RegisterEnumAsStringConvention()
+        private static void RegisterConventions()
         {
             var pack = new ConventionPack { new EnumRepresentationConvention(BsonType.String) };
 
             ConventionRegistry.Register("EnumStringConvention", pack, _ => true);
+
+            BsonClassMap.RegisterClassMap<WorkflowInstance>(cm =>
+            {
+                cm.AutoMap();
+                cm.SetIgnoreExtraElements(true);
+            });
         }
     }
 }