Remove dependency on Newtonsoft.Json from Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost (#81562)

Author: Copilot

src/Workspaces/MSBuild/BuildHost/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.csproj

@@ -44,9 +44,9 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.Build.Locator" PrivateAssets="All" />
     <PackageReference Include="System.Collections.Immutable" />
-    <PackageReference Include="Newtonsoft.Json" />
     <PackageReference Include="Microsoft.IO.Redist" Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp'" />
     <PackageReference Include="System.Threading.Tasks.Extensions" Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp'" />
+    <PackageReference Include="System.Text.Json" Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp'" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="..\..\..\Compilers\Core\Portable\InternalUtilities\*.cs" Link="InternalUtilities\%(FileName).cs" />

src/Workspaces/MSBuild/BuildHost/Rpc/Contracts/JsonSettings.cs

@@ -3,27 +3,30 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Text;
-using Newtonsoft.Json;
-using Newtonsoft.Json.Serialization;
+using System.Text.Encodings.Web;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using System.Text.Unicode;
 
 namespace Microsoft.CodeAnalysis.MSBuild;
 
 internal static class JsonSettings
 {
     public static readonly Encoding StreamEncoding = new UTF8Encoding(encoderShouldEmitUTF8Identifier: false);
 
-    public static readonly JsonSerializerSettings SingleLineSerializerSettings = new()
+    public static readonly JsonSerializerOptions SingleLineSerializerOptions = new()
     {
-        // Setting Formatting.None ensures each is serialized to it's own line, which we implicitly rely on
-        Formatting = Newtonsoft.Json.Formatting.None,
-
         // We use nulls for optional things, so doesn't matter
-        NullValueHandling = NullValueHandling.Ignore,
+        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
 
-        ContractResolver = new CamelCasePropertyNamesContractResolver(),
+        PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
 
         // We escape all non-ASCII characters. Because we're writing to stdin/stdout, on Windows codepages could be set that might interfere with Unicode, especially on build machines.
-        // By escaping all non-ASCII it means the JOSN stream itself is ASCII and thus can't be impacted by codepage issues.
-        StringEscapeHandling = StringEscapeHandling.EscapeNonAscii
+        // By escaping all non-ASCII it means the JSON stream itself is ASCII and thus can't be impacted by codepage issues.
+        // JavaScriptEncoder.Create(UnicodeRanges.BasicLatin) only allows BasicLatin (ASCII 0x00-0x7F) to be unescaped.
+        Encoder = JavaScriptEncoder.Create(UnicodeRanges.BasicLatin),
+
+        // Ensure WriteIndented is false (which is the default) so each message is serialized to its own line
+        WriteIndented = false
     };
 }

src/Workspaces/MSBuild/BuildHost/Rpc/Contracts/Request.cs

@@ -3,7 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Collections.Immutable;
-using Newtonsoft.Json.Linq;
+using System.Text.Json;
 
 namespace Microsoft.CodeAnalysis.MSBuild;
 
@@ -24,5 +24,5 @@ internal sealed class Request
     /// </summary>
     public required string Method { get; init; }
 
-    public required ImmutableArray<JToken> Parameters { get; init; }
+    public required ImmutableArray<JsonElement> Parameters { get; init; }
 }

src/Workspaces/MSBuild/BuildHost/Rpc/Contracts/Response.cs

@@ -2,14 +2,14 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using Newtonsoft.Json.Linq;
+using System.Text.Json;
 
 namespace Microsoft.CodeAnalysis.MSBuild;
 
 internal sealed class Response
 {
     public int Id { get; init; }
-    public JToken? Value { get; init; }
+    public JsonElement? Value { get; init; }
     public string? Exception { get; init; }
 }
 

src/Workspaces/MSBuild/BuildHost/Rpc/RpcServer.cs

@@ -8,10 +8,9 @@
 using System.IO;
 using System.IO.Pipes;
 using System.Reflection;
+using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
-using Newtonsoft.Json;
-using Newtonsoft.Json.Linq;
 using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.MSBuild;
@@ -68,7 +67,7 @@ public async Task RunAsync()
 
             try
             {
-                request = JsonConvert.DeserializeObject<Request>(line);
+                request = JsonSerializer.Deserialize<Request>(line, JsonSettings.SingleLineSerializerOptions);
                 Contract.ThrowIfNull(request);
             }
             catch (Exception e)
@@ -133,7 +132,7 @@ private async Task ProcessRequestAsync(Request request)
                 if (i == methodParameters.Length - 1 && lastParameterIsCancellationToken)
                     arguments[i] = CancellationToken.None;
                 else
-                    arguments[i] = request.Parameters[i].ToObject(methodParameters[i].ParameterType);
+                    arguments[i] = request.Parameters[i].Deserialize(methodParameters[i].ParameterType, JsonSettings.SingleLineSerializerOptions);
             }
 
             var result = method.Invoke(rpcTarget, arguments);
@@ -156,7 +155,7 @@ private async Task ProcessRequestAsync(Request request)
                 }
             }
 
-            response = new Response { Id = request.Id, Value = result is not null ? JToken.FromObject(result) : null };
+            response = new Response { Id = request.Id, Value = result is not null ? JsonSerializer.SerializeToElement(result, JsonSettings.SingleLineSerializerOptions) : null };
         }
         catch (Exception e)
         {
@@ -166,7 +165,7 @@ private async Task ProcessRequestAsync(Request request)
             response = new Response { Id = request.Id, Exception = $"An exception of type {e.GetType()} was thrown: {e.Message}" };
         }
 
-        var responseJson = JsonConvert.SerializeObject(response, JsonSettings.SingleLineSerializerSettings);
+        var responseJson = JsonSerializer.Serialize(response, JsonSettings.SingleLineSerializerOptions);
 
 #if DEBUG
         // Assert we didn't put a newline in this, since if we did the receiving side won't know how to parse it

src/Workspaces/MSBuild/Core/Microsoft.CodeAnalysis.Workspaces.MSBuild.csproj

@@ -25,7 +25,6 @@
     <PackageReference Include="Microsoft.Build.Framework" />
     <PackageReference Include="Microsoft.Extensions.Logging" />
     <PackageReference Include="Microsoft.VisualStudio.SolutionPersistence" />
-    <PackageReference Include="Newtonsoft.Json" />
     <!--
       Since System.Text.Json is part of the .NET BCL we do not want to add
       it as a package reference. Doing so will pin the version to what we use

src/Workspaces/MSBuild/Core/Rpc/RpcClient.cs

@@ -7,10 +7,9 @@
 using System.Collections.Generic;
 using System.IO;
 using System.IO.Pipes;
+using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
-using Newtonsoft.Json;
-using Newtonsoft.Json.Linq;
 using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.MSBuild;
@@ -60,7 +59,7 @@ public void Start()
                     Response? response;
                     try
                     {
-                        response = JsonConvert.DeserializeObject<Response>(line);
+                        response = JsonSerializer.Deserialize<Response>(line, JsonSettings.SingleLineSerializerOptions);
                     }
                     catch (JsonException ex)
                     {
@@ -89,7 +88,7 @@ public void Start()
                             try
                             {
                                 // response.Value might be null if the response was in fact null.
-                                var result = response.Value?.ToObject(expectedType);
+                                var result = response.Value?.Deserialize(expectedType, JsonSettings.SingleLineSerializerOptions);
                                 completionSource.SetResult(result);
                             }
                             catch (Exception ex)
@@ -155,10 +154,10 @@ public async Task<T> InvokeAsync<T>(int targetObject, string methodName, List<ob
             Id = requestId,
             TargetObject = targetObject,
             Method = methodName,
-            Parameters = parameters.SelectAsArray(static p => p is not null ? JToken.FromObject(p) : JValue.CreateNull())
+            Parameters = parameters.SelectAsArray(static p => JsonSerializer.SerializeToElement(p, JsonSettings.SingleLineSerializerOptions))
         };
 
-        var requestJson = JsonConvert.SerializeObject(request, JsonSettings.SingleLineSerializerSettings) + Environment.NewLine;
+        var requestJson = JsonSerializer.Serialize(request, JsonSettings.SingleLineSerializerOptions) + Environment.NewLine;
         var requestJsonBytes = JsonSettings.StreamEncoding.GetBytes(requestJson);
 
         try