Prevent invoking property 'init' method (dotnet#41293)

godspeedu · Aug 25, 2020 · d9fe9db · d9fe9db
1 parent e94dc2f
commit d9fe9db
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Showing 5 changed files with 85 additions and 2 deletions.
diff --git a/...braries/Microsoft.CSharp/src/Microsoft/CSharp/RuntimeBinder/Semantics/ExpressionBinder.cs b/...braries/Microsoft.CSharp/src/Microsoft/CSharp/RuntimeBinder/Semantics/ExpressionBinder.cs
@@ -841,7 +841,7 @@ private void CheckLvalue(Expr expr, CheckLvalueKind kind)
             {
                 case ExpressionKind.Property:
                     ExprProperty prop = (ExprProperty)expr;
-                    Debug.Assert(!prop.MethWithTypeSet);
+                    Debug.Assert(!prop.MethWithTypeSet || ExprProperty.HasIsExternalInitModifier(prop.MethWithTypeSet));
                     // Assigning to a property without a setter.
                     // If we have
                     // bool? b = true; (bool)b = false;

diff --git a/src/libraries/Microsoft.CSharp/src/Microsoft/CSharp/RuntimeBinder/Semantics/Tree/Property.cs b/src/libraries/Microsoft.CSharp/src/Microsoft/CSharp/RuntimeBinder/Semantics/Tree/Property.cs
@@ -1,6 +1,9 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Linq;
+using System.Reflection;
+
 namespace Microsoft.CSharp.RuntimeBinder.Semantics
 {
     internal sealed class ExprProperty : ExprWithArgs
@@ -28,7 +31,10 @@ public ExprProperty(CType type, Expr pOptionalObjectThrough, Expr pOptionalArgum
             if (mwtSet != null)
             {
                 MethWithTypeSet = mwtSet;
-                Flags = EXPRFLAG.EXF_LVALUE;
+                if (!HasIsExternalInitModifier(mwtSet))
+                {
+                    Flags = EXPRFLAG.EXF_LVALUE;
+                }
             }
         }
 
@@ -39,5 +45,12 @@ public ExprProperty(CType type, Expr pOptionalObjectThrough, Expr pOptionalArgum
         public MethWithType MethWithTypeSet { get; }
 
         public override SymWithType GetSymWithType() => PropWithTypeSlot;
+
+        internal static bool HasIsExternalInitModifier(MethWithType mwtSet)
+        {
+            var types = (mwtSet.Meth()?.AssociatedMemberInfo as MethodInfo)?.ReturnParameter.GetRequiredCustomModifiers();
+            return types != null &&
+                types.Any(type => type.Name == "IsExternalInit" && !type.IsNested && type.Namespace == "System.Runtime.CompilerServices");
+        }
     }
 }
diff --git a/src/libraries/Microsoft.CSharp/tests/BindingErrors.cs b/src/libraries/Microsoft.CSharp/tests/BindingErrors.cs
@@ -560,5 +560,65 @@ public void AllowStringIndexerAccess()
             char c = d.get_Chars(2);
             Assert.Equal('c', c);
         }
+
+        private sealed class InitOnlyProperty
+        {
+            public InitOnlyProperty() { }
+            public InitOnlyProperty(int value)
+            {
+                ((dynamic)this).P = value;
+            }
+            public int P { get; init; }
+            public int Q
+            {
+                get { return P; }
+                init { ((dynamic)this).P = value; }
+            }
+        }
+
+        [Fact]
+        [SkipOnTargetFramework(TargetFrameworkMonikers.NetFramework)]
+        public void InitOnlyProperty_Set()
+        {
+            dynamic d = new InitOnlyProperty();
+            Assert.Throws<RuntimeBinderException>(() => d.P = 1);
+        }
+
+        [Fact]
+        public void InitOnlyProperty_SetAccessor()
+        {
+            dynamic d = new InitOnlyProperty();
+            Assert.Throws<RuntimeBinderException>(() => d.set_P(1));
+        }
+
+        [Fact]
+        [SkipOnTargetFramework(TargetFrameworkMonikers.NetFramework)]
+        public void InitOnlyProperty_SetInConstructor()
+        {
+            Assert.Throws<RuntimeBinderException>(() => new InitOnlyProperty(1));
+        }
+
+        [Fact]
+        [SkipOnTargetFramework(TargetFrameworkMonikers.NetFramework)]
+        public void InitOnlyProperty_SetInInitAccessor()
+        {
+            Assert.Throws<RuntimeBinderException>(() => new InitOnlyProperty() { Q = 1 });
+        }
+
+        [Fact]
+        [SkipOnTargetFramework(TargetFrameworkMonikers.NetFramework)]
+        public void InitOnlyProperty_Increment()
+        {
+            dynamic d = new InitOnlyProperty();
+            Assert.Throws<RuntimeBinderException>(() => d.P++);
+        }
+
+        [Fact]
+        [SkipOnTargetFramework(TargetFrameworkMonikers.NetFramework)]
+        public void InitOnlyProperty_CompoundAssignment()
+        {
+            dynamic d = new InitOnlyProperty();
+            Assert.Throws<RuntimeBinderException>(() => d.P += 1);
+        }
     }
 }
diff --git a/src/libraries/Microsoft.CSharp/tests/IsExternalInit.cs b/src/libraries/Microsoft.CSharp/tests/IsExternalInit.cs
@@ -0,0 +1,9 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Runtime.CompilerServices
+{
+    public sealed class IsExternalInit
+    {
+    }
+}
diff --git a/src/libraries/Microsoft.CSharp/tests/Microsoft.CSharp.Tests.csproj b/src/libraries/Microsoft.CSharp/tests/Microsoft.CSharp.Tests.csproj
@@ -26,6 +26,7 @@
     <Compile Include="IntegerBinaryOperationTests.cs" />
     <Compile Include="IntegerUnaryOperationTests.cs" />
     <Compile Include="IsEventTests.cs" />
+    <Compile Include="IsExternalInit.cs" />
     <Compile Include="NamedArgumentTests.cs" />
     <Compile Include="NullableEnumUnaryOperationTest.cs" />
     <Compile Include="RuntimeBinderExceptionTests.cs" />