Fix NullReferenceException when NoWarn is empty

TunnelVisionLabs.ReferenceAssemblyAnnotator/AnnotatorBuildTask.cs

@@ -19,7 +19,6 @@ public AnnotatorBuildTask()
             TargetFrameworkDirectories = null!;
             AnnotatedReferenceAssemblyDirectory = null!;
             OutputPath = null!;
-            DisabledWarnings = null!;
         }
 
         [Required]
@@ -50,7 +49,7 @@ public string OutputPath
             set;
         }
 
-        public string DisabledWarnings
+        public string? DisabledWarnings
         {
             get;
             set;

TunnelVisionLabs.ReferenceAssemblyAnnotator/SuppressibleLoggingHelper.cs

@@ -14,7 +14,7 @@ internal readonly struct SuppressibleLoggingHelper
         private readonly ImmutableHashSet<string> _disabledWarnings;
         private readonly string _requiredPrefix;
 
-        public SuppressibleLoggingHelper(TaskLoggingHelper helper, string requiredPrefix, string disabledWarnings)
+        public SuppressibleLoggingHelper(TaskLoggingHelper helper, string requiredPrefix, string? disabledWarnings)
         {
             _helper = helper;
 
@@ -24,10 +24,11 @@ public SuppressibleLoggingHelper(TaskLoggingHelper helper, string requiredPrefix
             _requiredPrefix = requiredPrefix;
 
             _disabledWarnings = disabledWarnings
-                .Split(new[] { ',', ';' }, StringSplitOptions.RemoveEmptyEntries)
+                ?.Split(new[] { ',', ';' }, StringSplitOptions.RemoveEmptyEntries)
                 .Select(item => item.Trim())
                 .Where(item => item.StartsWith(requiredPrefix, StringComparison.Ordinal))
-                .ToImmutableHashSet(StringComparer.Ordinal);
+                .ToImmutableHashSet(StringComparer.Ordinal)
+                ?? ImmutableHashSet<string>.Empty;
         }
 
         public void LogWarning(string warningCode, string message, params object?[] messageArgs)

appveyor.yml

@@ -17,6 +17,9 @@ test_script:
 - git clean -dxf tests
 - msbuild /restore tests/RefVersion3.1.0 /warnaserror /nr:false /v:m
 - git clean -dxf tests
+# No /warnaserror because WarningsNotAsErrors is not respected
+- msbuild /restore tests/NoDisabledWarnings /p:TreatWarningsAsErrors=true /nr:false /v:m
+- git clean -dxf tests
 - msbuild /restore tests/SingleTFM /p:TestFramework=net35 /warnaserror /nr:false /v:m
 - git clean -dxf tests
 - msbuild /restore tests/SingleTFM /p:TestFramework=net48 /warnaserror /nr:false /v:m
@@ -44,6 +47,8 @@ test_script:
 - git clean -dxf tests
 - dotnet msbuild -restore tests/RefVersion3.1.0 -warnaserror -nr:false -v:m
 - git clean -dxf tests
+- dotnet msbuild -restore tests/NoDisabledWarnings -warnaserror -nr:false -v:m
+- git clean -dxf tests
 - dotnet msbuild -restore tests/SingleTFM -p:TestFramework=net35 -warnaserror -nr:false -v:m
 - git clean -dxf tests
 - dotnet msbuild -restore tests/SingleTFM -p:TestFramework=net48 -warnaserror -nr:false -v:m

tests/NoDisabledWarnings/Class1.cs

@@ -0,0 +1,19 @@
+using System.Collections.Generic;
+using System.Data.SqlClient;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Sample1
+{
+    public class Class1
+    {
+        public static void M(SqlConnection connection, [AllowNull] string? x)
+        {
+            if (!string.IsNullOrEmpty(x))
+            {
+                x.ToString();
+            }
+
+            _ = EqualityComparer<string?>.Default.GetHashCode(x);
+        }
+    }
+}

tests/NoDisabledWarnings/NoDisabledWarnings.csproj

@@ -0,0 +1,32 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFrameworks>net35;net48;netstandard1.6;netstandard2.0;netstandard2.1;netcoreapp1.0;netcoreapp1.1;netcoreapp2.0;netcoreapp2.1;netcoreapp3.0;netcoreapp3.1</TargetFrameworks>
+    <LangVersion>8</LangVersion>
+    <Nullable>enable</Nullable>
+    <WarningsNotAsErrors>RA1000</WarningsNotAsErrors>
+    <NoWarn></NoWarn>
+  </PropertyGroup>
+
+  <PropertyGroup>
+    <!-- NuGet cannot restore packages for netcoreapp1.0: https://github.com/NuGet/Home/issues/7414 -->
+    <DisableImplicitNuGetFallbackFolder>true</DisableImplicitNuGetFallbackFolder>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(TargetFramework)' == 'netcoreapp1.0' OR '$(TargetFramework)' == 'netcoreapp1.1'">
+    <!-- CS1701: Assuming assembly reference "Assembly Name #1" matches "Assembly Name #2", you may need to supply runtime policy -->
+    <WarningsNotAsErrors>$(WarningsNotAsErrors),CS1701</WarningsNotAsErrors>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <!-- https://github.com/dotnet/core-sdk/issues/2022 -->
+    <PackageReference Condition="'$(TargetFramework)' == 'net35'" Include="jnm2.ReferenceAssemblies.net35" Version="1.0.0" PrivateAssets="all" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Condition="'$(TargetFramework)' != 'net35'" Include="System.Data.SqlClient" Version="4.8.0" />
+    <PackageReference Include="TunnelVisionLabs.ReferenceAssemblyAnnotator" Version="1.0.0-alpha.*" PrivateAssets="all" />
+    <PackageDownload Include="Microsoft.NETCore.App.Ref" Version="[3.0.0]" />
+  </ItemGroup>
+
+</Project>