ensure that Content items are available during restore to un-break Razor (#49783)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: baronfel

src/Cli/Microsoft.DotNet.Cli.Utils/Constants.cs

@@ -19,7 +19,9 @@ public static class Constants
 
     public static readonly string MSBUILD_EXE_PATH = nameof(MSBUILD_EXE_PATH);
     public static readonly string MSBuildExtensionsPath = nameof(MSBuildExtensionsPath);
+
     public static readonly string EnableDefaultItems = nameof(EnableDefaultItems);
+    public static readonly string EnableDefaultContentItems = nameof(EnableDefaultContentItems);
     public static readonly string EnableDefaultCompileItems = nameof(EnableDefaultCompileItems);
     public static readonly string EnableDefaultEmbeddedResourceItems = nameof(EnableDefaultEmbeddedResourceItems);
     public static readonly string EnableDefaultNoneItems = nameof(EnableDefaultNoneItems);

src/Cli/dotnet/Commands/Restore/RestoringCommand.cs

@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Frozen;
 using System.Collections.ObjectModel;
 using Microsoft.DotNet.Cli.Commands.MSBuild;
 using Microsoft.DotNet.Cli.Commands.Workload.Install;
@@ -12,7 +11,6 @@ namespace Microsoft.DotNet.Cli.Commands.Restore;
 
 public class RestoringCommand : MSBuildForwardingApp
 {
-
     /// <summary>
     /// This dictionary contains properties that are set to disable the default items
     /// that are added to the project by default. These Item types are not needed
@@ -22,7 +20,9 @@ public class RestoringCommand : MSBuildForwardingApp
     public static ReadOnlyDictionary<string, string> RestoreOptimizationProperties =>
         new(new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase)
         {
-            { Constants.EnableDefaultItems, "false" },
+            // note that we do not disable all default items - Razor at least needs Content
+            // in order to do implicit PackageReferences if Razor files are present
+            { Constants.EnableDefaultCompileItems, "false" },
             { Constants.EnableDefaultEmbeddedResourceItems, "false" },
             { Constants.EnableDefaultNoneItems, "false" },
         });