Avoid calling ctor on abstract type during deserialization (dotnet/corefx#39481)

Commit migrated from https://github.com/dotnet/corefx/commit/a7efd2a2b3c638b5490547ad6beca128ba5d7bfe

diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/ReflectionEmitMemberAccessor.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/ReflectionEmitMemberAccessor.cs
index 1bc9d97..f41f7cb 100644 (file)
--- a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/ReflectionEmitMemberAccessor.cs
+++ b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/ReflectionEmitMemberAccessor.cs
@@ -16,6 +16,11 @@ namespace System.Text.Json
             Debug.Assert(type != null);
             ConstructorInfo realMethod = type.GetConstructor(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance, binder: null, Type.EmptyTypes, modifiers: null);
 
+            if (type.IsAbstract)
+            {
+                return null;
+            }
+
             if (realMethod == null && !type.IsValueType)
             {
                 return null;

diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/ReflectionMemberAccessor.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/ReflectionMemberAccessor.cs
index b152ddc..d5afac2 100644 (file)
--- a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/ReflectionMemberAccessor.cs
+++ b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/ReflectionMemberAccessor.cs
@@ -29,6 +29,11 @@ namespace System.Text.Json
             Debug.Assert(type != null);
             ConstructorInfo realMethod = type.GetConstructor(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance, binder: null, Type.EmptyTypes, modifiers: null);
 
+            if (type.IsAbstract)
+            {
+                return null;
+            }
+
             if (realMethod == null && !type.IsValueType)
             {
                 return null;

diff --git a/src/libraries/System.Text.Json/tests/Serialization/Value.ReadTests.cs b/src/libraries/System.Text.Json/tests/Serialization/Value.ReadTests.cs
index 4e5d830..2838a6e 100644 (file)
--- a/src/libraries/System.Text.Json/tests/Serialization/Value.ReadTests.cs
+++ b/src/libraries/System.Text.Json/tests/Serialization/Value.ReadTests.cs
@@ -283,6 +283,7 @@ namespace System.Text.Json.Serialization.Tests
             Assert.Throws<JsonException>(() => JsonSerializer.Deserialize<char>("1"));
             Assert.Throws<JsonException>(() => JsonSerializer.Deserialize<char?>("1"));
 
+            // This throws because Enum is an abstract type.
             Assert.Throws<JsonException>(() => JsonSerializer.Deserialize<Enum>(unexpectedString));
         }