Handle binding to initialized abstract members (#93090)

If an abstract member is encountered in an object graph we should only throw if it's not already initialized.
dotnet · Oct 6, 2023 · 4dcad85 · 4dcad85
1 parent 915a2f9
commit 4dcad85
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Showing 3 changed files with 28 additions and 6 deletions.
diff --git a/src/libraries/Microsoft.Extensions.Configuration.Binder/gen/Emitter/CoreBindingHelpers.cs b/src/libraries/Microsoft.Extensions.Configuration.Binder/gen/Emitter/CoreBindingHelpers.cs
@@ -1047,15 +1047,13 @@ void EmitBindingLogic(string instanceToBindExpr, InitializationKind initKind)
                     else
                     {
                         Debug.Assert(!type.IsValueType);
-
+                        EmitStartBlock($"if ({instanceToBindExpr} is not null)");
+                        EmitBindCoreCall();
+                        EmitEndBlock();
                         if (type is ObjectSpec { InitExceptionMessage: string exMsg })
                         {
+                            EmitStartBlock("else");
                             _writer.WriteLine($@"throw new {Identifier.InvalidOperationException}(""{exMsg}"");");
-                        }
-                        else
-                        {
-                            EmitStartBlock($"if ({instanceToBindExpr} is not null)");
-                            EmitBindCoreCall();
                             EmitEndBlock();
                         }
                     }

diff --git a/...soft.Extensions.Configuration.Binder/tests/Common/ConfigurationBinderTests.TestClasses.cs b/...soft.Extensions.Configuration.Binder/tests/Common/ConfigurationBinderTests.TestClasses.cs
@@ -842,6 +842,11 @@ internal sealed class DerivedWithAnotherProp : AbstractBase
         {
             public int Value2 { get; set; }
         }
+
+        internal class ClassWithAbstractProp
+        {
+            public AbstractBase AbstractProp { get; set; }
+        }
 
         internal class ClassWithAbstractCtorParam
         {

diff --git a/...raries/Microsoft.Extensions.Configuration.Binder/tests/Common/ConfigurationBinderTests.cs b/...raries/Microsoft.Extensions.Configuration.Binder/tests/Common/ConfigurationBinderTests.cs
@@ -2324,6 +2324,25 @@ public static void TestBindingAbstractMember_AsCtorParam()
             Assert.Throws<InvalidOperationException>(configuration.Get<ClassWithOptionalAbstractCtorParam>);
         }
 
+        [Fact]
+        public static void TestBindingInitializedAbstractMember()
+        {
+            IConfiguration configuration = TestHelpers.GetConfigurationFromJsonString(@"{ ""AbstractProp"": {""Value"":1} }");
+            ClassWithAbstractProp c = new();
+            c.AbstractProp = new Derived();
+            configuration.Bind(c);
+            Assert.Equal(1, c.AbstractProp.Value);            
+        }
+
+        [Fact]
+        public static void TestBindingUninitializedAbstractMember()
+        {
+            IConfiguration configuration = TestHelpers.GetConfigurationFromJsonString(@"{ ""AbstractProp"": {""Value"":1} }");
+            ClassWithAbstractProp c = new();
+            c.AbstractProp = null;
+            Assert.Throws<InvalidOperationException>(() => configuration.Bind(c));        
+        }
+
         [Fact]
         public void GetIConfigurationSection()
         {