#4649 Feature/4649 thread safe broken rules

Source/Csla/Rules/BrokenRulesCollection.cs

@@ -6,6 +6,7 @@
 // <summary>A collection of currently broken rules.</summary>
 //-----------------------------------------------------------------------
 
+using System.Collections.ObjectModel;
 using Csla.Properties;
 using Csla.Serialization.Mobile;
 
@@ -446,8 +447,11 @@ public void AddRange(List<BrokenRule> list)
     {
       if (list is null)
         throw new ArgumentNullException(nameof(list));
-      foreach (var item in list)
-        Add(item);
+      lock (_syncRoot)
+      {
+        foreach (var item in list)
+          Add(item);
+      }
     }
 
     /// <summary>
@@ -479,5 +483,19 @@ protected override void OnSetState(SerializationInfo info)
       InformationCount = info.GetValue<int>("_infoCount");
       base.OnSetState(info);
     }
+
+    /// <summary>
+    /// Returns a thread-safe copy of the current broken rules.
+    /// This method should be used instead of ToList() when a copy of the 
+    /// broken rules list is desired that 
+    /// </summary>
+    /// <returns>A new <see cref="ReadOnlyCollection{BrokenRule}"/> containing the broken rules at the time of the call.</returns>
+    public ReadOnlyCollection<BrokenRule> ToThreadSafeList()
+    {
+      lock (_syncRoot)
+      {
+        return this.ToList().AsReadOnly();
+      }
+    }
   }
 }

Source/tests/Csla.test/BizRules/BusinessRuleTests.cs

@@ -55,6 +55,31 @@ public void DisableDataAnnotationsScan()
       obj.IsValid.Should().BeTrue();
     }
 
+    [TestMethod]
+    [TestCategory("ThreadSafety")]
+    public async Task ToThreadSafeList_WithConcurrentModification_DoesNotThrowException()
+    {
+      SetScanForDataAnnotations(true);
+
+      var portal = _testDIContext.ServiceProvider.GetRequiredService<IDataPortal<TestBusinessRule3>>();
+      var obj = portal.Create();
+
+      obj.FirstName = "";
+      obj.LastName = "";
+      var list = obj.GetBrokenRules().ToThreadSafeList();
+
+      foreach (var item in list)
+      {
+        await Task.Run(() =>
+        {
+          obj.FirstName = "Drop Dead";
+          obj.LastName = "Fred";
+        }).ConfigureAwait(false);
+      }
+
+      Assert.AreEqual(2, list.Count);
+    }
+
     private void SetScanForDataAnnotations(bool enable)
     {
       var options = _testDIContext.ServiceProvider.GetRequiredService<CslaOptions>();
@@ -96,4 +121,29 @@ private void Create()
       BusinessRules.CheckRules();
     }
   }
+
+  public class TestBusinessRule3 : BusinessBase<TestBusinessRule3>
+  {
+    public static readonly PropertyInfo<string> FirstNameProperty = RegisterProperty<string>(nameof(FirstName));
+    [Required]
+    public string FirstName
+    {
+      get => GetProperty(FirstNameProperty);
+      set => SetProperty(FirstNameProperty, value);
+    }
+
+    public static readonly PropertyInfo<string> LastNameProperty = RegisterProperty<string>(nameof(LastName));
+    [Required]
+    public string LastName
+    {
+      get => GetProperty(LastNameProperty);
+      set => SetProperty(LastNameProperty, value);
+    }
+
+    [Create]
+    private void Create()
+    {
+      BusinessRules.CheckRules();
+    }
+  }
 }