Fix regression in how GetData APIs swallow all exceptions. (#12656)

restore behavior of
1. app with BinaryFormatter enabled SetData("custom format", new List<Point>(){})
2. app with BInaryFormatter disabled GetData("custom format")

NET8 and NET9 were returning an empty memory stream, I regressed it to throw the NotSupportedException from the spot where we detect that BinaryFormatter is disabled.
After this change I retain the NotSupportedException only in the Typed Get APIs

src/System.Windows.Forms/src/System/Windows/Forms/OLE/DataObject.Composition.BinaryFormatUtilities.cs

@@ -139,7 +139,8 @@ record = stream.Decode(out recordMap);
                 // 1. Doesn't allow arrays that have a non-zero base index (can't create these in C# or VB)
                 // 2. Only allows IObjectReference types that contain primitives (to avoid observable cycle
                 //    dependencies to indeterminate state)
-                // But it usually requires a resolver.
+                // But it usually requires a resolver. Resolver is not available in the legacy mode,
+                // so we will fall back to BinaryFormatter in that case.
                 if (LocalAppContextSwitches.ClipboardDragDropEnableNrbfSerialization)
                 {
                     try

src/System.Windows.Forms/src/System/Windows/Forms/OLE/DataObject.Composition.NativeToWinFormsAdapter.cs

@@ -278,7 +278,7 @@ private static bool TryGetObjectFromDataObject<T>(
                         result = TryGetIStreamData(dataObject, format, resolver, legacyMode, out data);
                     }
                 }
-                catch (Exception e) when (e is not NotSupportedException)
+                catch (Exception e) when (legacyMode || e is not NotSupportedException)
                 {
                     Debug.Fail(e.ToString());
                 }
@@ -337,9 +337,8 @@ private static bool TryGetHGLOBALData<T>(
                     data = default;
                     doNotContinue = true;
                 }
-                catch (Exception ex) when (ex is not NotSupportedException)
+                catch (Exception ex) when (legacyMode || ex is not NotSupportedException)
                 {
-                    // Should we catch SerializationExceptions that wrap NotSupported when called from the typed API?
                     Debug.WriteLine(ex.ToString());
                 }
                 finally

src/System.Windows.Forms/tests/ComDisabledTests/ClipboardComTests.cs

@@ -27,6 +27,7 @@ public void Clipboard_SetDataAsJson_ReturnsExpected()
     {
         SimpleTestData testData = new() { X = 1, Y = 1 };
 
+        using BinaryFormatterScope scope = new(enable: false);
         Clipboard.SetDataAsJson("testData", testData);
         ITypedDataObject dataObject = Clipboard.GetDataObject().Should().BeAssignableTo<ITypedDataObject>().Subject;
         dataObject.GetDataPresent("testData").Should().BeTrue();
@@ -40,6 +41,7 @@ public void Clipboard_SetDataObject_WithJson_ReturnsExpected(bool copy)
     {
         SimpleTestData testData = new() { X = 1, Y = 1 };
 
+        using BinaryFormatterScope scope = new(enable: false);
         DataObject dataObject = new();
         dataObject.SetDataAsJson("testData", testData);
 

src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/ClipboardTests.cs

@@ -908,17 +908,31 @@ public void Clipboard_SetDataAsJson_WithGeneric_ReturnsExpected()
         string format = "list";
         Clipboard.SetDataAsJson(format, generic1);
         DataObject dataObject = Clipboard.GetDataObject().Should().BeOfType<DataObject>().Subject;
-        Action a = () => dataObject.TestAccessor().Dynamic._innerData.GetData(format);
-        // We do not handle List<Point>
-        a.Should().Throw<NotSupportedException>();
+
+        // We do not handle List<Point>, this is a wrong API to read JSON-serialized payload.
+        // This call returns an unfilled MemoryStream due to the BinaryFormatter being disabled,
+        // same as it was in .NET9 for any payload.
+        dataObject.GetData(format).Should().BeOfType<MemoryStream>();
+
+        using (BinaryFormatterInClipboardDragDropScope scope = new(enable: true))
+        using (BinaryFormatterScope scope2 = new(enable: true))
+        {
+            // BinaryFormatter will not find our fake System.Private.Windows.VirtualJson assembly
+            // and will throw a SerializationException.
+            var result1 = dataObject.GetData(format);
+            result1.Should().BeOfType<MemoryStream>();
+        }
+
         Clipboard.TryGetData(format, out List<Point>? points).Should().BeTrue();
         points.Should().BeEquivalentTo(generic1);
 
+        // List of primitives is an intrinsic type, formatters are bypassed.
         List<int> generic2 = [];
         Clipboard.SetDataAsJson(format, generic2);
         dataObject = Clipboard.GetDataObject().Should().BeOfType<DataObject>().Subject;
-        a = () => dataObject.TestAccessor().Dynamic._innerData.GetData(format);
-        a.Should().NotThrow();
+
+        dataObject.GetData(format).Should().BeEquivalentTo(generic2);
+
         Clipboard.TryGetData(format, out List<int>? intList).Should().BeTrue();
         intList.Should().BeEquivalentTo(generic2);
     }
@@ -943,11 +957,11 @@ public void Clipboard_SetDataAsJson_GetData()
         SimpleTestData testData = new() { X = 1, Y = 1 };
         // Note that this simulates out of process scenario.
         Clipboard.SetDataAsJson("test", testData);
-        Action a = () => Clipboard.GetData("test");
-        a.Should().Throw<NotSupportedException>();
+
+        Clipboard.GetData("test").Should().BeOfType<MemoryStream>();
 
         using BinaryFormatterInClipboardDragDropScope scope = new(enable: true);
-        a.Should().Throw<NotSupportedException>();
+        Clipboard.GetData("test").Should().BeOfType<MemoryStream>();
 
         using BinaryFormatterScope scope2 = new(enable: true);
         Clipboard.GetData("test").Should().BeOfType<MemoryStream>();
@@ -1001,7 +1015,7 @@ public unsafe void Clipboard_Deserialize_FromStream_Manually()
         Clipboard.SetDataAsJson("testFormat", testData);
 
         // Manually retrieve the serialized stream.
-        ComTypes.IDataObject dataObject = Clipboard.GetDataObject().Should().BeAssignableTo<ComTypes.IDataObject>().Which;
+        ComTypes.IDataObject dataObject = Clipboard.GetDataObject().Should().BeAssignableTo<ComTypes.IDataObject>().Subject;
         ComTypes.FORMATETC formatetc = new()
         {
             cfFormat = (short)DataFormats.GetFormat("testFormat").Id,
@@ -1011,38 +1025,45 @@ public unsafe void Clipboard_Deserialize_FromStream_Manually()
         };
         dataObject.GetData(ref formatetc, out ComTypes.STGMEDIUM medium);
         HGLOBAL hglobal = (HGLOBAL)medium.unionmember;
-        Stream stream;
+        MemoryStream? stream = null;
         try
         {
-            void* buffer = PInvokeCore.GlobalLock(hglobal);
-            int size = (int)PInvokeCore.GlobalSize(hglobal);
-            byte[] bytes = new byte[size];
-            Marshal.Copy((nint)buffer, bytes, 0, size);
-            // this comes from DataObject.Composition.s_serializedObjectID
-            int index = 16;
-            stream = new MemoryStream(bytes, index, bytes.Length - index);
+            try
+            {
+                void* buffer = PInvokeCore.GlobalLock(hglobal);
+                int size = (int)PInvokeCore.GlobalSize(hglobal);
+                byte[] bytes = new byte[size];
+                Marshal.Copy((nint)buffer, bytes, 0, size);
+                // this comes from DataObject.Composition.s_serializedObjectID
+                int index = 16;
+                stream = new MemoryStream(bytes, index, bytes.Length - index);
+            }
+            finally
+            {
+                PInvokeCore.GlobalUnlock(hglobal);
+            }
+
+            stream.Should().NotBeNull();
+            // Use NrbfDecoder to decode the stream and rehydrate the type.
+            SerializationRecord record = NrbfDecoder.Decode(stream);
+            ClassRecord types = record.Should().BeAssignableTo<ClassRecord>().Subject;
+            types.HasMember("<JsonBytes>k__BackingField").Should().BeTrue();
+            types.HasMember("<InnerTypeAssemblyQualifiedName>k__BackingField").Should().BeTrue();
+            SZArrayRecord<byte> byteData = types.GetRawValue("<JsonBytes>k__BackingField").Should().BeAssignableTo<SZArrayRecord<byte>>().Subject;
+            string innerTypeAssemblyQualifiedName = types.GetRawValue("<InnerTypeAssemblyQualifiedName>k__BackingField").Should().BeOfType<string>().Subject;
+            TypeName.TryParse(innerTypeAssemblyQualifiedName, out TypeName? innerTypeName).Should().BeTrue();
+            TypeName checkedResult = innerTypeName.Should().BeOfType<TypeName>().Subject;
+            // These should not be the same since we take TypeForwardedFromAttribute name into account during serialization,
+            // which changes the assembly name.
+            typeof(SimpleTestData).AssemblyQualifiedName.Should().NotBe(checkedResult.AssemblyQualifiedName);
+            typeof(SimpleTestData).ToTypeName().Matches(checkedResult).Should().BeTrue();
+
+            JsonSerializer.Deserialize(byteData.GetArray(), typeof(SimpleTestData)).Should().BeEquivalentTo(testData);
         }
         finally
         {
-            PInvokeCore.GlobalUnlock(hglobal);
+            stream?.Dispose();
         }
-
-        stream.Should().NotBeNull();
-        // Use NrbfDecoder to decode the stream and rehydrate the type.
-        SerializationRecord record = NrbfDecoder.Decode(stream);
-        ClassRecord types = record.Should().BeAssignableTo<ClassRecord>().Which;
-        types.HasMember("<JsonBytes>k__BackingField").Should().BeTrue();
-        types.HasMember("<InnerTypeAssemblyQualifiedName>k__BackingField").Should().BeTrue();
-        SZArrayRecord<byte> byteData = types.GetRawValue("<JsonBytes>k__BackingField").Should().BeAssignableTo<SZArrayRecord<byte>>().Subject;
-        string innerTypeAssemblyQualifiedName = types.GetRawValue("<InnerTypeAssemblyQualifiedName>k__BackingField").Should().BeOfType<string>().Subject;
-        TypeName.TryParse(innerTypeAssemblyQualifiedName, out TypeName? innerTypeName).Should().BeTrue();
-        TypeName checkedResult = innerTypeName.Should().BeOfType<TypeName>().Subject;
-        // These should not be the same since we take TypeForwardedFromAttribute name into account during serialization,
-        // which changes the assembly name.
-        typeof(SimpleTestData).AssemblyQualifiedName.Should().NotBe(checkedResult.AssemblyQualifiedName);
-        typeof(SimpleTestData).ToTypeName().Matches(checkedResult).Should().BeTrue();
-
-        JsonSerializer.Deserialize(byteData.GetArray(), typeof(SimpleTestData)).Should().BeEquivalentTo(testData);
     }
 
     [WinFormsFact]