From 599c6a5cd69fd0fb565ee2071c88359e17ae668e Mon Sep 17 00:00:00 2001
From: Sipke Schoorstra <sipkeschoorstra@outlook.com>
Date: Thu, 24 Dec 2020 21:38:45 +0100
Subject: [PATCH] Fix workflow execution

This fixes an issue where blocking activities would not actually block workflow execution from continuing, due to the workflow runner continuing to schedule the posted activities.
---
 .../Services/Models/WorkflowExecutionContext.cs      | 10 +++-------
 src/core/Elsa.Core/Services/WorkflowRunner.cs        | 12 +++++-------
 2 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/src/core/Elsa.Abstractions/Services/Models/WorkflowExecutionContext.cs b/src/core/Elsa.Abstractions/Services/Models/WorkflowExecutionContext.cs
index e7bd00c61..14c822cd2 100644
--- a/src/core/Elsa.Abstractions/Services/Models/WorkflowExecutionContext.cs
+++ b/src/core/Elsa.Abstractions/Services/Models/WorkflowExecutionContext.cs
@@ -94,14 +94,10 @@ namespace Elsa.Services.Models
         public IActivityBlueprint? GetActivityBlueprintById(string id) => WorkflowBlueprint.Activities.FirstOrDefault(x => x.Id == id);
         public IActivityBlueprint? GetActivityBlueprintByName(string name) => WorkflowBlueprint.Activities.FirstOrDefault(x => x.Name == name);
 
-        public void SchedulePostActivities()
+        public void SchedulePostActivity()
         {
-            var activities = WorkflowInstance.PostScheduledActivities.Reverse();
-
-            foreach (var activity in activities) 
-                ScheduleActivity(activity);
-
-            WorkflowInstance.PostScheduledActivities.Clear();
+            var activity = WorkflowInstance.PostScheduledActivities.Pop();
+            ScheduleActivity(activity);
         }
 
         public object? GetOutputFrom(string activityName)
diff --git a/src/core/Elsa.Core/Services/WorkflowRunner.cs b/src/core/Elsa.Core/Services/WorkflowRunner.cs
index 22cda1f96..95ba74600 100644
--- a/src/core/Elsa.Core/Services/WorkflowRunner.cs
+++ b/src/core/Elsa.Core/Services/WorkflowRunner.cs
@@ -286,15 +286,13 @@ namespace Elsa.Services
                 activityOperation = Execute;
                 workflowExecutionContext.CompletePass();
 
+                // Exit execution loop if workflow has any other status than Running (i.e. Suspended). Otherwise continue the loop.
+                if (workflowExecutionContext.Status != WorkflowStatus.Running)
+                    break;
+                
                 // If there are no more scheduled activities, schedule any post-scheduled activities.
                 if (!workflowExecutionContext.HasScheduledActivities && workflowExecutionContext.HasPostScheduledActivities)
-                {
-                    workflowExecutionContext.SchedulePostActivities();
-
-                    // Exit execution loop if workflow has any other status than Running (i.e. Suspended). Otherwise continue the loop.
-                    if (workflowExecutionContext.Status != WorkflowStatus.Running)
-                        break;
-                }
+                    workflowExecutionContext.SchedulePostActivity();
             }
 
             if (workflowExecutionContext.HasBlockingActivities)