From 50659d9c2a21aa4e79260d0e2f920f02769225cb Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Wed, 15 Dec 2021 23:12:19 +0100
Subject: [PATCH] Enable nullable reference checking via .props file.

The Nullable annotations on netstandard2.0 are incomplete and incorrect in places. Ignore nullable warnings on netstandard2.0 and make them errors on later target frameworks.
---
 build/NullableEnable.props                            | 11 +++++++++++
 src/Avalonia.Diagnostics/Avalonia.Diagnostics.csproj  |  2 +-
 src/Avalonia.Input/Avalonia.Input.csproj              |  2 +-
 src/Avalonia.ReactiveUI/Avalonia.ReactiveUI.csproj    |  3 +--
 src/Markup/Avalonia.Markup/Avalonia.Markup.csproj     |  3 +--
 .../Avalonia.Web.Blazor/Avalonia.Web.Blazor.csproj    |  4 ++--
 6 files changed, 17 insertions(+), 8 deletions(-)
 create mode 100644 build/NullableEnable.props

diff --git a/build/NullableEnable.props b/build/NullableEnable.props
new file mode 100644
index 0000000000..cf5f9069d4
--- /dev/null
+++ b/build/NullableEnable.props
@@ -0,0 +1,11 @@
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <!-- 
+    The Nullable annotations on netstandard2.0 are incomplete and incorrect in places. Ignore
+    nullable warnings on netstandard2.0 and make them errors on later target frameworks.
+  -->
+  <PropertyGroup>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors Condition="'$(TargetFramework)' != 'netstandard2.0'">$(WarningsAsErrors);nullable</WarningsAsErrors>
+    <NoWarn Condition="'$(TargetFramework)' == 'netstandard2.0'">$(NoWarn);nullable</NoWarn>
+  </PropertyGroup>
+</Project>
diff --git a/src/Avalonia.Diagnostics/Avalonia.Diagnostics.csproj b/src/Avalonia.Diagnostics/Avalonia.Diagnostics.csproj
index 7d64e3d82f..871821dd70 100644
--- a/src/Avalonia.Diagnostics/Avalonia.Diagnostics.csproj
+++ b/src/Avalonia.Diagnostics/Avalonia.Diagnostics.csproj
@@ -3,7 +3,6 @@
     <TargetFrameworks>netstandard2.0;net6.0</TargetFrameworks>
     <RootNamespace>Avalonia</RootNamespace>
     <PackageId>Avalonia.Diagnostics</PackageId>
-    <Nullable>enable</Nullable>
   </PropertyGroup>
   <ItemGroup>
     <Compile Update="**\*.xaml.cs">
@@ -34,4 +33,5 @@
   <Import Project="..\..\build\Rx.props" />
   <Import Project="..\..\build\BuildTargets.targets" />
   <Import Project="..\..\build\ApiDiff.props" />
+  <Import Project="..\..\build\NullableEnable.props" />
 </Project>
diff --git a/src/Avalonia.Input/Avalonia.Input.csproj b/src/Avalonia.Input/Avalonia.Input.csproj
index 8b33fdcc02..a1640a62f8 100644
--- a/src/Avalonia.Input/Avalonia.Input.csproj
+++ b/src/Avalonia.Input/Avalonia.Input.csproj
@@ -1,7 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;net6.0</TargetFrameworks>
-    <Nullable>Enable</Nullable>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="..\Avalonia.Base\Metadata\NullableAttributes.cs" Link="NullableAttributes.cs" />
@@ -15,4 +14,5 @@
   </ItemGroup>  
   <Import Project="..\..\build\Rx.props" />
   <Import Project="..\..\build\ApiDiff.props" />
+  <Import Project="..\..\build\NullableEnable.props" />
 </Project>
diff --git a/src/Avalonia.ReactiveUI/Avalonia.ReactiveUI.csproj b/src/Avalonia.ReactiveUI/Avalonia.ReactiveUI.csproj
index a5f4b8073a..189b156569 100644
--- a/src/Avalonia.ReactiveUI/Avalonia.ReactiveUI.csproj
+++ b/src/Avalonia.ReactiveUI/Avalonia.ReactiveUI.csproj
@@ -3,8 +3,6 @@
     <TargetFrameworks>netstandard2.0;net6.0</TargetFrameworks>
     <PackageId>Avalonia.ReactiveUI</PackageId>
     <SignAssembly>false</SignAssembly>
-    <Nullable>enable</Nullable>
-    <WarningsAsErrors>nullable</WarningsAsErrors>
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\packages\Avalonia\Avalonia.csproj" />
@@ -12,4 +10,5 @@
   <Import Project="..\..\build\Rx.props" />
   <Import Project="..\..\build\ReactiveUI.props" />
   <Import Project="..\..\build\ApiDiff.props" />
+  <Import Project="..\..\build\NullableEnable.props" />
 </Project>
diff --git a/src/Markup/Avalonia.Markup/Avalonia.Markup.csproj b/src/Markup/Avalonia.Markup/Avalonia.Markup.csproj
index e560732b41..c8f60924c6 100644
--- a/src/Markup/Avalonia.Markup/Avalonia.Markup.csproj
+++ b/src/Markup/Avalonia.Markup/Avalonia.Markup.csproj
@@ -2,8 +2,6 @@
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;net6.0</TargetFrameworks>
     <RootNamespace>Avalonia</RootNamespace>
-    <Nullable>Enable</Nullable>
-    <WarningsAsErrors>CS8600;CS8602;CS8603</WarningsAsErrors>
   </PropertyGroup>
   <ItemGroup>
     <None Remove="Markup\Parsers\Nodes\ExpressionGrammer" />
@@ -19,4 +17,5 @@
   <Import Project="..\..\..\build\Rx.props" />
   <Import Project="..\..\..\build\System.Memory.props" />
   <Import Project="..\..\..\build\ApiDiff.props" />
+  <Import Project="..\..\..\build\NullableEnable.props" />
 </Project>
diff --git a/src/Web/Avalonia.Web.Blazor/Avalonia.Web.Blazor.csproj b/src/Web/Avalonia.Web.Blazor/Avalonia.Web.Blazor.csproj
index 8b7babe5b1..94350b40cf 100644
--- a/src/Web/Avalonia.Web.Blazor/Avalonia.Web.Blazor.csproj
+++ b/src/Web/Avalonia.Web.Blazor/Avalonia.Web.Blazor.csproj
@@ -2,7 +2,6 @@
 
   <PropertyGroup>
     <TargetFramework>net6.0</TargetFramework>
-    <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <PackageId>Avalonia.Web.Blazor</PackageId>
     <LangVersion>preview</LangVersion>
@@ -32,7 +31,8 @@
   <Import Project="..\..\..\build\BuildTargets.targets" />
   <Import Project="..\..\..\build\SkiaSharp.props" />
   <Import Project="..\..\..\build\HarfBuzzSharp.props" />
-
+  <Import Project="..\..\..\build\NullableEnable.props" />
+  
   <ItemGroup>
     <Content Include="*.props">
       <Pack>true</Pack>