Revert "Scale back [Serializable] CoreFX types (#19742)"

This reverts commit 6dd451f51451a7d0ceea6104b51bd17005e9a0e6.

6 files changed, 48 insertions, 0 deletions

diff --git a/src/System.IO.FileSystem/src/System/IO/DirectoryInfo.cs b/src/System.IO.FileSystem/src/System/IO/DirectoryInfo.cs
index 03c7311565..4b4a274997 100644
--- a/src/System.IO.FileSystem/src/System/IO/DirectoryInfo.cs
+++ b/src/System.IO.FileSystem/src/System/IO/DirectoryInfo.cs
@@ -10,6 +10,7 @@ using System.Runtime.Serialization;
 
 namespace System.IO
 {
+    [Serializable]
     public sealed partial class DirectoryInfo : FileSystemInfo
     {
         [System.Security.SecuritySafeCritical]
diff --git a/src/System.IO.FileSystem/src/System/IO/FileInfo.cs b/src/System.IO.FileSystem/src/System/IO/FileInfo.cs
index 8ff606c857..e13fcfe9f5 100644
--- a/src/System.IO.FileSystem/src/System/IO/FileInfo.cs
+++ b/src/System.IO.FileSystem/src/System/IO/FileInfo.cs
@@ -15,6 +15,7 @@ namespace System.IO
 {
     // Class for creating FileStream objects, and some basic file management
     // routines such as Delete, etc.
+    [Serializable]
     public sealed partial class FileInfo : FileSystemInfo
     {
         private String _name;
diff --git a/src/System.IO.FileSystem/src/System/IO/FileSystemInfo.cs b/src/System.IO.FileSystem/src/System/IO/FileSystemInfo.cs
index 31a8432b74..5002a4c828 100644
--- a/src/System.IO.FileSystem/src/System/IO/FileSystemInfo.cs
+++ b/src/System.IO.FileSystem/src/System/IO/FileSystemInfo.cs
@@ -13,6 +13,7 @@ using System.Runtime.Versioning;
 
 namespace System.IO
 {
+    [Serializable]
     public abstract partial class FileSystemInfo : MarshalByRefObject, ISerializable
     {
         protected String FullPath;          // fully qualified path of the file or directory
diff --git a/src/System.IO.FileSystem/tests/DirectoryInfo/Serialization.cs b/src/System.IO.FileSystem/tests/DirectoryInfo/Serialization.cs
new file mode 100644
index 0000000000..0395821da3
--- /dev/null
+++ b/src/System.IO.FileSystem/tests/DirectoryInfo/Serialization.cs
@@ -0,0 +1,22 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Runtime.Serialization.Formatters.Tests;
+using Xunit;
+
+namespace System.IO.Tests
+{
+    public partial class DirectoryInfo_Serialization : FileSystemTest
+    {
+        [Fact]
+        public void SerializeDeserialize_Roundtrip()
+        {
+            var orig = new DirectoryInfo("SomePath");
+            DirectoryInfo cloned = BinaryFormatterHelpers.Clone(orig);
+            Assert.Equal(orig.Name, cloned.Name);
+            Assert.Equal(orig.FullName, cloned.FullName);
+            Assert.Equal(orig.ToString(), cloned.ToString());
+        }
+    }
+}
diff --git a/src/System.IO.FileSystem/tests/FileInfo/Serialization.cs b/src/System.IO.FileSystem/tests/FileInfo/Serialization.cs
new file mode 100644
index 0000000000..275c88ddcd
--- /dev/null
+++ b/src/System.IO.FileSystem/tests/FileInfo/Serialization.cs
@@ -0,0 +1,22 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Runtime.Serialization.Formatters.Tests;
+using Xunit;
+
+namespace System.IO.Tests
+{
+    public class FileInfo_Serialization : FileSystemTest
+    {
+        [Fact]
+        public void SerializeDeserialize_Roundtrip()
+        {
+            var orig = new DirectoryInfo("SomePath");
+            DirectoryInfo cloned = BinaryFormatterHelpers.Clone(orig);
+            Assert.Equal(orig.Name, cloned.Name);
+            Assert.Equal(orig.FullName, cloned.FullName);
+            Assert.Equal(orig.ToString(), cloned.ToString());
+        }
+    }
+}
diff --git a/src/System.IO.FileSystem/tests/System.IO.FileSystem.Tests.csproj b/src/System.IO.FileSystem/tests/System.IO.FileSystem.Tests.csproj
index 02cbadaf0d..7e346d3068 100644
--- a/src/System.IO.FileSystem/tests/System.IO.FileSystem.Tests.csproj
+++ b/src/System.IO.FileSystem/tests/System.IO.FileSystem.Tests.csproj
@@ -18,6 +18,7 @@
     <Compile Include="FileInfo\Replace.cs" />
     <Compile Include="FileStream\Handle.cs" />
     <Compile Include="Directory\GetLogicalDrives.cs" />
+    <Compile Include="DirectoryInfo\Serialization.cs" />
     <Compile Include="FileStream\EndRead.cs" />
     <Compile Include="FileStream\EndWrite.cs" />
     <Compile Include="FileStream\LockUnlock.cs" />