Add support for abstract class parameters in settings

When a parameter is an abstract class, now accept the type name of a concrete subclass that has a default constructor ( the same way interfaces are supported)
ite-klass · Nov 8, 2017 · f19f196 · f19f196
1 parent 9f27375
commit f19f196
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Showing 3 changed files with 40 additions and 1 deletion.
diff --git a/src/Serilog/Settings/KeyValuePairs/SettingValueConversions.cs b/src/Serilog/Settings/KeyValuePairs/SettingValueConversions.cs
@@ -51,7 +51,7 @@ public static object ConvertToType(string value, Type toType)
             if (convertor != null)
                 return convertor(value);
 
-            if (toTypeInfo.IsInterface && !string.IsNullOrWhiteSpace(value))
+            if ((toTypeInfo.IsInterface || toTypeInfo.IsAbstract) && !string.IsNullOrWhiteSpace(value))
             {
                 var type = Type.GetType(value.Trim(), throwOnError: false);
                 if (type != null)

diff --git a/test/Serilog.Tests/Settings/SettingValueConversionsTests.cs b/test/Serilog.Tests/Settings/SettingValueConversionsTests.cs
@@ -3,6 +3,7 @@
 using Serilog.Formatting;
 using Serilog.Formatting.Json;
 using Serilog.Settings.KeyValuePairs;
+using Serilog.Tests.Support;
 using Xunit;
 
 namespace Serilog.Tests.Settings
@@ -51,6 +52,21 @@ public void StringValuesConvertToDefaultInstancesIfTargetIsInterface()
             Assert.IsType<JsonFormatter>(result);
         }
 
+        [Fact]
+        public void StringValuesConvertToDefaultInstancesIfTargetIsAbstractClass()
+        {
+            var result = SettingValueConversions.ConvertToType("Serilog.Tests.Support.DummyConcreteClassWithDefaultConstructor, Serilog.Tests", typeof(DummyAbstractClass));
+            Assert.IsType<DummyConcreteClassWithDefaultConstructor>(result);
+        }
+
+        [Fact]
+        public void StringValuesThrowsWhenMissingDefaultConstructorIfTargetIsAbstractClass()
+        {
+            var value = "Serilog.Tests.Support.DummyConcreteClassWithoutDefaultConstructor, Serilog.Tests";
+            Assert.Throws<InvalidOperationException>(() =>
+                SettingValueConversions.ConvertToType(value, typeof(DummyAbstractClass)));
+        }
+
         [Theory]
         [InlineData("3.14:21:18.986", 3 /*days*/, 14 /*hours*/, 21 /*min*/, 18 /*sec*/, 986 /*ms*/)]
         [InlineData("4", 4, 0, 0, 0, 0)] // minimal : days

diff --git a/test/Serilog.Tests/Support/ClassHierarchy.cs b/test/Serilog.Tests/Support/ClassHierarchy.cs
@@ -0,0 +1,23 @@
+namespace Serilog.Tests.Support
+{
+
+    public abstract class DummyAbstractClass
+    {
+    }
+
+    public class DummyConcreteClassWithDefaultConstructor
+    {
+        // ReSharper disable once UnusedParameter.Local
+        public DummyConcreteClassWithDefaultConstructor(string param = "")
+        {
+        }
+    }
+
+    public class DummyConcreteClassWithoutDefaultConstructor
+    {
+        // ReSharper disable once UnusedParameter.Local
+        public DummyConcreteClassWithoutDefaultConstructor(string param)
+        {
+        }
+    }
+}