Fix TypeExtensions ToTypeString method Exception.

Fix TypeExtensions ToTypeString method throws if invoked on a generic class without specify the generic type Closes #609
CommunityToolkit · Mar 11, 2023 · 354e56f · 354e56f
1 parent 1537e98
commit 354e56f
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Showing 2 changed files with 6 additions and 2 deletions.
diff --git a/src/CommunityToolkit.Diagnostics/Extensions/TypeExtensions.cs b/src/CommunityToolkit.Diagnostics/Extensions/TypeExtensions.cs
@@ -161,8 +161,10 @@ private static string FormatDisplayString(Type type, int genericTypeOffset, Read
             displayName = type.Name;
         }
 
-        // If the type is nested, recursively format the hierarchy as well
-        if (type.IsNested)
+        // If the type is nested, recursively format the hierarchy as well,
+        // unless the type is a generic type parameter, in that case type.DeclaringType returns the parent class that defined the generic type parameter,
+        // however the current execution of FormatDisplayString it's been invoked recursively while trying to format the parent class so we need to skip this recursive call.
+        if (type.IsNested && !type.IsGenericParameter)
         {
             return $"{FormatDisplayString(type.DeclaringType!, genericTypeOffset, typeArguments)}.{displayName}";
         }

diff --git a/tests/CommunityToolkit.Diagnostics.UnitTests/Extensions/Test_TypeExtensions.cs b/tests/CommunityToolkit.Diagnostics.UnitTests/Extensions/Test_TypeExtensions.cs
@@ -45,8 +45,10 @@ public void Test_TypeExtensions_GenericTypes(string name, Type type)
     [DataRow("CommunityToolkit.Diagnostics.UnitTests.Extensions.Test_TypeExtensions.Animal", typeof(Animal))]
     [DataRow("CommunityToolkit.Diagnostics.UnitTests.Extensions.Test_TypeExtensions.Animal.Cat", typeof(Animal.Cat))]
     [DataRow("CommunityToolkit.Diagnostics.UnitTests.Extensions.Test_TypeExtensions.Animal.Dog", typeof(Animal.Dog))]
+    [DataRow("CommunityToolkit.Diagnostics.UnitTests.Extensions.Test_TypeExtensions.Animal.Rabbit<CommunityToolkit.Diagnostics.UnitTests.Extensions.T>", typeof(Animal.Rabbit<>))]
     [DataRow("CommunityToolkit.Diagnostics.UnitTests.Extensions.Test_TypeExtensions.Animal.Rabbit<int?>", typeof(Animal.Rabbit<int?>))]
     [DataRow("CommunityToolkit.Diagnostics.UnitTests.Extensions.Test_TypeExtensions.Animal.Rabbit<string>", typeof(Animal.Rabbit<string>))]
+    [DataRow("CommunityToolkit.Diagnostics.UnitTests.Extensions.Test_TypeExtensions.Animal.Rabbit<CommunityToolkit.Diagnostics.UnitTests.Extensions.Test_TypeExtensions.Animal.Dog>", typeof(Animal.Rabbit<Animal.Dog>))]
     [DataRow("CommunityToolkit.Diagnostics.UnitTests.Extensions.Test_TypeExtensions.Animal.Rabbit<int>.Foo", typeof(Animal.Rabbit<int>.Foo))]
     [DataRow("CommunityToolkit.Diagnostics.UnitTests.Extensions.Test_TypeExtensions.Animal.Rabbit<(string, int)?>.Foo", typeof(Animal.Rabbit<(string, int)?>.Foo))]
     [DataRow("CommunityToolkit.Diagnostics.UnitTests.Extensions.Test_TypeExtensions.Animal.Rabbit<int>.Foo<string>", typeof(Animal.Rabbit<int>.Foo<string>))]