Fix issue serializing null options in VB (#78895)

Author: CyrusNajmabadi

src/Workspaces/VisualBasic/Portable/Serialization/VisualBasicOptionsSerializationService.vb

@@ -23,7 +23,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Serialization
 
             Dim vbOptions = DirectCast(options, VisualBasicCompilationOptions)
 
-            writer.WriteArray(vbOptions.GlobalImports.SelectAsArray(Function(g) g.Name), Sub(w, n) w.WriteString(n))
+            writer.WriteArray(vbOptions.GlobalImports.NullToEmpty().SelectAsArray(Function(g) g?.Name), Sub(w, n) w.WriteString(n))
             writer.WriteString(vbOptions.RootNamespace)
             writer.WriteInt32(vbOptions.OptionStrict)
             writer.WriteBoolean(vbOptions.OptionInfer)
@@ -81,7 +81,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Serialization
             Dim assemblyIdentityComparer = tuple.assemblyIdentityComparer
             Dim strongNameProvider = tuple.strongNameProvider
 
-            Dim globalImports = GlobalImport.Parse(reader.ReadArray(Function(r) r.ReadString()))
+            Dim globalImports = GlobalImport.Parse(reader.ReadArray(Function(r) r.ReadString()).WhereNotNull())
             Dim rootNamespace = reader.ReadString()
             Dim optionStrict = CType(reader.ReadInt32(), OptionStrict)
             Dim optionInfer = reader.ReadBoolean()

src/Workspaces/VisualBasicTest/Serialization/OptionsSerializationTests.vb

@@ -0,0 +1,41 @@
+' 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.
+
+Imports System.IO
+Imports System.Threading
+Imports Microsoft.CodeAnalysis.Serialization
+Imports Microsoft.CodeAnalysis.Test.Utilities
+Imports Roslyn.Test.Utilities
+Imports Roslyn.Utilities
+Imports Xunit
+
+Namespace Microsoft.CodeAnalysis.VisualBasic.UnitTests.Serialization
+    <UseExportProvider>
+    Public NotInheritable Class OptionsSerializationTests
+        <Fact, WorkItem("https://devdiv.visualstudio.com/DevDiv/_workitems/edit/2325692")>
+        Public Sub TestNullGlobalImport()
+            Dim options = New VisualBasicCompilationOptions(
+                OutputKind.ConsoleApplication,
+                "module",
+                globalImports:={Nothing})
+
+            Using workspace = New AdhocWorkspace()
+                Dim service = workspace.Services.GetLanguageServices(LanguageNames.VisualBasic).GetService(Of IOptionsSerializationService)()
+
+                Using stream = New MemoryStream()
+                    Dim writer = New ObjectWriter(stream, leaveOpen:=True)
+                    service.WriteTo(options, writer, CancellationToken.None)
+                    stream.Position = 0
+
+                    Dim reader = ObjectReader.TryGetReader(stream, leaveOpen:=True)
+                    Dim serializedOptions = DirectCast(
+                        service.ReadCompilationOptionsFrom(reader, CancellationToken.None),
+                        VisualBasicCompilationOptions)
+
+                    Assert.Empty(serializedOptions.GlobalImports)
+                End Using
+            End Using
+        End Sub
+    End Class
+End Namespace