Fix target object emit (#125)

* Rewrite PopParent to properly reset PropertyTargetObject * Add ProvideValueTarget_TargetObject_Is_Valid_After_Nested_PushPop test
kekekeks · Sep 14, 2024 · e524acf · e524acf
1 parent e13c3ef
commit e524acf
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Showing 2 changed files with 53 additions and 8 deletions.
diff --git a/src/XamlX/IL/RuntimeContext.cs b/src/XamlX/IL/RuntimeContext.cs
@@ -444,22 +444,34 @@ private void EmitPushPopParent(IXamlTypeBuilder<IXamlILEmitter> builder, IXamlTy
                 .LdThisFld(parentListField)
                 .EmitCall(objectListType.GetMethod(m => m.Name == "get_Count"))
                 .Ldc_I4(1).Emit(OpCodes.Sub).Stloc(idx);
-                // this.PropertyTargetObject = _parents[idx];
+
+            pop
+                // _parents.RemoveAt(idx);
+                .LdThisFld(parentListField)
+                .Ldloc(idx)
+                .EmitCall(objectListType.GetMethod(m => m.Name == "RemoveAt"));
+
+            // this.PropertyTargetObject = idx != 0 ? _parents[idx - 1] : null;
             if (TargetObjectField != null)
             {
+                var elseLabel = pop.DefineLabel();
+                var endIfLabel = pop.DefineLabel();
                 pop
-                    .Ldarg_0()
-                    .LdThisFld(parentListField)
+                    .Ldarg(0)
                     .Ldloc(idx)
+                    .Brfalse(elseLabel) // if `idx != 0`
+                    .LdThisFld(parentListField) // then '_parents[idx - 1]'
+                    .Ldloc(idx)
+                    .Ldc_I4(1).Emit(OpCodes.Sub)
                     .EmitCall(objectListType.GetMethod(m => m.Name == "get_Item"))
+                    .Br(endIfLabel)
+                    .MarkLabel(elseLabel) // else
+                    .Ldnull() // then 'null'
+                    .MarkLabel(endIfLabel) // endif
                     .Stfld(TargetObjectField);
             }
-                // _parents.RemoveAt(idx);
-            pop
-                .LdThisFld(parentListField)
-                .Ldloc(idx).EmitCall(objectListType.GetMethod(m => m.Name == "RemoveAt"))
-                .Ret();
 
+            pop.Ret();
         }
 
         private IXamlMethodBuilder<IXamlILEmitter> ImplementInterfacePropertyGetter(IXamlTypeBuilder<IXamlILEmitter> builder ,

diff --git a/tests/XamlParserTests/ServiceProviderTests.cs b/tests/XamlParserTests/ServiceProviderTests.cs
@@ -11,6 +11,8 @@ namespace XamlParserTests
 {
     public class CallbackExtension
     {
+        public object? Nested { get; set; }
+
         public object? ProvideValue(IServiceProvider provider)
         {
             return provider.GetRequiredService<CallbackExtensionCallback>()(provider);
@@ -168,6 +170,37 @@ public void ProvideValueTarget_Provides_Info_About_Properties()
             Assert.Equal(2, num);
         }
 
+        [Fact]
+        public void ProvideValueTarget_TargetObject_Is_Valid_After_Nested_PushPop()
+        {
+            var num = 0;
+            CompileAndRun(@"
+<ServiceProviderTestsClass xmlns='test' 
+    Property='{Callback Nested={Callback}}'
+    ServiceProviderTests.AttachedProperty='{Callback}'
+/>", sp =>
+            {
+                var pt = sp.GetRequiredService<ITestProvideValueTarget>();
+                if (num == 0)
+                {
+                    Assert.IsType<CallbackExtension>(pt.TargetObject);
+                    Assert.Equal("Nested", pt.TargetProperty);
+                }
+                else if (num == 1)
+                {
+                    Assert.IsType<ServiceProviderTestsClass>(pt.TargetObject);
+                    Assert.Equal("Property", pt.TargetProperty);
+                }
+                else if (num == 2)
+                {
+                    Assert.IsType<ServiceProviderTestsClass>(pt.TargetObject);
+                    Assert.Equal("AttachedProperty", pt.TargetProperty);
+                }
+                num++;
+                return num.ToString();
+            }, null);
+            Assert.Equal(3, num);
+        }
 
         class InnerProvider : IServiceProvider, ITestRootObjectProvider
         {