From f5b32f84ea6af403ac85057d33b5553dcd80ebed Mon Sep 17 00:00:00 2001
From: James Courtney <jcourtney@gmail.com>
Date: Wed, 25 Jan 2023 11:39:58 -0800
Subject: [PATCH] Add C# 8 Build Step (#362)

Validate C#8 compatibility
---
 .github/workflows/charp8build.yml             | 55 +++++++++++++++++++
 .../SchemaModel/RpcServiceSchemaModel.cs      | 11 +++-
 src/Tests/CompileTests/CSharp8/CSharp8.csproj | 24 ++++++++
 3 files changed, 87 insertions(+), 3 deletions(-)
 create mode 100644 .github/workflows/charp8build.yml
 create mode 100644 src/Tests/CompileTests/CSharp8/CSharp8.csproj

diff --git a/.github/workflows/charp8build.yml b/.github/workflows/charp8build.yml
new file mode 100644
index 00000000..35073a1f
--- /dev/null
+++ b/.github/workflows/charp8build.yml
@@ -0,0 +1,55 @@
+name: C# 8 Build Verification
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: windows-2019
+    env:
+      AppVeyorBuild: true
+    steps:
+    - uses: actions/checkout@v2
+    
+    - name: Setup .NET 7
+      uses: actions/setup-dotnet@v1
+      with:
+        dotnet-version: 7.0.x
+        
+    - name: Setup .NET 6
+      uses: actions/setup-dotnet@v1
+      with:
+        dotnet-version: 6.0.x
+        
+    - name: Restore dependencies
+      working-directory: src
+      run: dotnet restore
+      
+    - name: Build FlatSharp.Compiler
+      working-directory: src/FlatSharp.Compiler
+      run: dotnet build -c Release
+      
+    - name: Run FlatSharp.Compiler
+      # You may pin to the exact commit or the version.
+      # uses: Amadevus/pwsh-script@97a8b211a5922816aa8a69ced41fa32f23477186
+      uses: Amadevus/pwsh-script@v2.0.3
+      with:
+        # PowerShell script to execute in Actions-hydrated context
+        script: |
+          $fbs = (gci -r src/tests/FlatsharpEndToEndTests/*.fbs | where Name -ne "AccessModifiers.fbs") -join ";"
+          dotnet src/FlatSharp.Compiler/bin/Release/net7.0/FlatSharp.Compiler.dll --nullable-warnings false --normalize-field-names true --input "$fbs" -o src/tests/CompileTests/CSharp8
+          
+    - name: Build
+      working-directory: src/tests/CompileTests/CSharp8
+      run: dotnet build -c Release
+      
+    - name: Upload Files
+      uses: actions/upload-artifact@v3
+      if: failure()
+      with:
+        name: generated-csharp
+        path: src/tests/CompileTests/CSharp8/**/*.*
diff --git a/src/FlatSharp.Compiler/SchemaModel/RpcServiceSchemaModel.cs b/src/FlatSharp.Compiler/SchemaModel/RpcServiceSchemaModel.cs
index 8f8e6068..917b2232 100644
--- a/src/FlatSharp.Compiler/SchemaModel/RpcServiceSchemaModel.cs
+++ b/src/FlatSharp.Compiler/SchemaModel/RpcServiceSchemaModel.cs
@@ -217,7 +217,7 @@ private void DefineServerBaseClass(CodeWriter writer, Dictionary<string, string>
             {
                 foreach (var method in this.calls)
                 {
-                    writer.AppendLine($".AddMethod({methodNameMap[method.Name]}, serviceImpl == null ? null : serviceImpl.{method.Name})");
+                    writer.AppendLine($".AddMethod({methodNameMap[method.Name]}, serviceImpl == null ? ({this.GetServerHandlerDelegateType(method)}?)null : serviceImpl.{method.Name})");
                 }
 
                 writer.AppendLine(".Build();");
@@ -234,7 +234,7 @@ private void DefineServerBaseClass(CodeWriter writer, Dictionary<string, string>
             foreach (var method in this.calls)
             {
                 string serverDelegate = GetServerHandlerDelegate(method);
-                writer.AppendLine($"serviceBinder.AddMethod({methodNameMap[method.Name]}, serviceImpl == null ? null : {serverDelegate});");
+                writer.AppendLine($"serviceBinder.AddMethod({methodNameMap[method.Name]}, serviceImpl == null ? ({this.GetServerHandlerDelegateType(method)}?)null : {serverDelegate});");
             }
             writer.AppendLine("#pragma warning restore CS8604");
         }
@@ -568,8 +568,13 @@ private void WriteNoRequestParameterMethod(
     }
 
     private string GetServerHandlerDelegate(RpcCallSchemaModel call)
+    {
+        return $"new {this.GetServerHandlerDelegateType(call)}(serviceImpl.{call.Name})";
+    }
+
+    private string GetServerHandlerDelegateType(RpcCallSchemaModel call)
     {
         string methodType = GetGrpcMethodType(call.StreamingType);
-        return $"new {GrpcCore}.{methodType}ServerMethod<{call.RequestType}, {call.ResponseType}>(serviceImpl.{call.Name})";
+        return $"{GrpcCore}.{methodType}ServerMethod<{call.RequestType}, {call.ResponseType}>";
     }
 }
diff --git a/src/Tests/CompileTests/CSharp8/CSharp8.csproj b/src/Tests/CompileTests/CSharp8/CSharp8.csproj
new file mode 100644
index 00000000..34587b25
--- /dev/null
+++ b/src/Tests/CompileTests/CSharp8/CSharp8.csproj
@@ -0,0 +1,24 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFrameworks>net472;netstandard2.0;netstandard2.1</TargetFrameworks>
+    <IsPackable>false</IsPackable>
+    <AssemblyName>CSharp8CompileTest</AssemblyName>
+    <RootNamespace>CSharp8CompileTest</RootNamespace>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <Nullable>annotations</Nullable>
+    <NoWarn>CS1591</NoWarn>
+    <LangVersion>8.0</LangVersion>
+  </PropertyGroup>
+  
+  <ItemGroup>
+    <PackageReference Include="Grpc.Core" Version="2.46.5" />
+    <PackageReference Include="Grpc.Core.Api" Version="2.49.0" />
+    <PackageReference Include="Microsoft.CSharp" Version="4.7.0" />
+    <PackageReference Include="System.Threading.Channels" Version="6.0.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\FlatSharp.Runtime\FlatSharp.Runtime.csproj" />
+  </ItemGroup>
+</Project>
+