From 2b77ac8fe0dcd614506a230f327907eb124c35ae Mon Sep 17 00:00:00 2001
From: Sipke Schoorstra <sipkeschoorstra@outlook.com>
Date: Fri, 28 May 2021 16:38:59 +0200
Subject: [PATCH] Handle potential null dictionary

---
 .../Services/ActivityPropertyProviders.cs     | 19 +++++++++++--------
 .../Workflows/ForEachWorkflow.cs              |  4 ++--
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/src/core/Elsa.Abstractions/Services/ActivityPropertyProviders.cs b/src/core/Elsa.Abstractions/Services/ActivityPropertyProviders.cs
index efe92e299..1a56897c8 100644
--- a/src/core/Elsa.Abstractions/Services/ActivityPropertyProviders.cs
+++ b/src/core/Elsa.Abstractions/Services/ActivityPropertyProviders.cs
@@ -36,13 +36,16 @@ namespace Elsa.Services
             properties[propertyName] = provider;
         }
 
-        public IDictionary<string, IActivityPropertyValueProvider> GetProviders(string activityId) => _providers.TryGetValue(activityId, out var properties) ? properties : new Dictionary<string, IActivityPropertyValueProvider>();
+        public IDictionary<string, IActivityPropertyValueProvider> GetProviders(string activityId) => 
+            _providers.TryGetValue(activityId, out var properties) 
+                ? properties ?? new Dictionary<string, IActivityPropertyValueProvider>() 
+                : new Dictionary<string, IActivityPropertyValueProvider>();
 
         public IActivityPropertyValueProvider? GetProvider(string activityId, string propertyName) =>
-            _providers.TryGetValue(activityId, out var properties) 
-            && properties != null 
-            && properties.TryGetValue(propertyName, out var provider) 
-                ? provider 
+            _providers.TryGetValue(activityId, out var properties)
+            && properties != null
+            && properties.TryGetValue(propertyName, out var provider)
+                ? provider
                 : null;
 
         public async ValueTask SetActivityPropertiesAsync(IActivity activity, ActivityExecutionContext activityExecutionContext, CancellationToken cancellationToken = default)
@@ -64,14 +67,14 @@ namespace Elsa.Services
                         var activityPropertyAttribute = property.GetCustomAttribute<ActivityPropertyAttribute>();
                         value = activityPropertyAttribute?.DefaultValue;
                     }
-                    
-                    if(value != null)
+
+                    if (value != null)
                     {
                         property.SetValue(activity, value);
                         activityExecutionContext.SetState(property.Name, value);
                     }
                 }
-                catch(Exception e)
+                catch (Exception e)
                 {
                     throw new CannotSetActivityPropertyValueException($@"An exception was thrown whilst setting '{activity?.GetType().Name}.{property.Name}'. See the inner exception for further details.", e);
                 }
diff --git a/test/integration/Elsa.Core.IntegrationTests/Workflows/ForEachWorkflow.cs b/test/integration/Elsa.Core.IntegrationTests/Workflows/ForEachWorkflow.cs
index 414b39c43..21f738806 100644
--- a/test/integration/Elsa.Core.IntegrationTests/Workflows/ForEachWorkflow.cs
+++ b/test/integration/Elsa.Core.IntegrationTests/Workflows/ForEachWorkflow.cs
@@ -22,8 +22,8 @@ namespace Elsa.Core.IntegrationTests.Workflows
                 .ForEach(
                     _items,
                     iterate => iterate
-                        .Then<WriteLine>(activity => activity.Set(x => x.Text, context => $"{context.Input}")).WithId("WriteLine")
-                        .Then<SignalReceived>() /* Block workflow.*/
+                        .Then<WriteLine>(activity => activity.WithText(context => $"{context.Input}")).WithId("WriteLine")
+                        .SignalReceived("The Signal") /* Block workflow.*/
                         .WriteLine("Resumed"))
                 .WriteLine("One iterations executing, rest is blocked");
         }