Merge pull request #174 from AArnott/nrt

Add nullable ref type annotations

Author: AArnott

src/Directory.Build.props

@@ -8,6 +8,7 @@
 
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <LangVersion>8</LangVersion>
+    <Nullable>enable</Nullable>
     <NoWarn>CS1591;CS1701</NoWarn>
     <UpdateXlfOnBuild Condition=" '$(UpdateXlfOnBuild)' == '' ">true</UpdateXlfOnBuild>
 
@@ -30,6 +31,7 @@
     <PackageReference Include="Nerdbank.GitVersioning" Version="3.2.31" PrivateAssets="all" />
     <PackageReference Include="StyleCop.Analyzers" Version="1.2.0-beta.205" PrivateAssets="all" />
     <PackageReference Include="MicroBuild.VisualStudio" Version="$(MicroBuildVersion)" PrivateAssets="all" />
+    <PackageReference Include="Microsoft.Net.Compilers.Toolset" Version="3.7.0" PrivateAssets="all" />
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0" PrivateAssets="All" />
   </ItemGroup>
   <ItemGroup>

src/Microsoft.VisualStudio.Composition.Analyzers/Microsoft.VisualStudio.Composition.Analyzers.csproj

@@ -15,6 +15,7 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="2.10.0" PrivateAssets="all" />
     <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="2.9.8" PrivateAssets="all" />
+    <PackageReference Include="Nullable" Version="1.3.0" PrivateAssets="all" />
   </ItemGroup>
 
   <ItemGroup>

src/Microsoft.VisualStudio.Composition.AppHost/CreateComposition.cs

@@ -77,7 +77,7 @@ public CreateComposition()
         /// <summary>
         /// Gets or sets a list of codes to suppress warnings for.
         /// </summary>
-        public string[] NoWarn { get; set; }
+        public string[]? NoWarn { get; set; }
 
         /// <summary>
         /// Gets or sets a value indicating whether to continue when errors occur while scanning MEF assemblies.
@@ -92,21 +92,21 @@ public CreateComposition()
         public bool ContinueOnCompositionErrors { get; set; }
 
         [Required]
-        public string CompositionCacheFile { get; set; }
+        public string CompositionCacheFile { get; set; } = null!;
 
-        public string DgmlOutputPath { get; set; }
+        public string? DgmlOutputPath { get; set; }
 
         /// <summary>
         /// Gets or sets the directory to write the discovery and composition log files.
         /// </summary>
         [Required]
-        public string LogOutputPath { get; set; }
+        public string LogOutputPath { get; set; } = null!;
 
         /// <summary>
         /// Gets or sets a list of files that were written during this task's execution.
         /// </summary>
         [Output]
-        public ITaskItem[] FileWrites { get; set; }
+        public ITaskItem[]? FileWrites { get; set; }
 
         /// <inheritdoc />
         public void Cancel() => this.cts.Cancel();
@@ -171,7 +171,7 @@ public override bool Execute()
                 if (!string.IsNullOrEmpty(this.DgmlOutputPath))
                 {
                     configuration.CreateDgml().Save(this.DgmlOutputPath);
-                    this.writtenFiles.Add(this.DgmlOutputPath);
+                    this.writtenFiles.Add(this.DgmlOutputPath!);
                 }
 
                 this.CancellationToken.ThrowIfCancellationRequested();
@@ -304,13 +304,13 @@ private string GetMEFAssemblyFullPath(ITaskItem taskItem)
             return Path.GetFullPath(taskItem.GetMetadata("FullPath"));
         }
 
-        private Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
+        private Assembly? CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
         {
             // apply any existing policy
             AssemblyName referenceName = new AssemblyName(AppDomain.CurrentDomain.ApplyPolicy(args.Name));
 
             string fileName = referenceName.Name + ".dll";
-            Assembly assm;
+            Assembly? assm;
 
             // Look through user-specified assembly lists.
             foreach (var candidate in this.catalogAssemblyPaths.Concat(this.ReferenceAssemblies.Select(i => i.GetMetadata("FullPath"))))
@@ -336,7 +336,7 @@ private Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs a
             }
 
             // look next to requesting assembly
-            string assemblyPath = args.RequestingAssembly?.Location;
+            string? assemblyPath = args.RequestingAssembly?.Location;
             if (!string.IsNullOrEmpty(assemblyPath))
             {
                 probingPath = Path.Combine(Path.GetDirectoryName(assemblyPath), fileName);
@@ -390,7 +390,7 @@ private Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs a
         /// <param name="minimumVersion">Minimum version to consider.</param>
         /// <param name="assembly">loaded assembly.</param>
         /// <returns>true if assembly was loaded.</returns>
-        private bool Probe(string filePath, Version minimumVersion, out Assembly assembly)
+        private bool Probe(string filePath, Version minimumVersion, [NotNullWhen(true)] out Assembly? assembly)
         {
             if (File.Exists(filePath))
             {

src/Microsoft.VisualStudio.Composition.AppHost/CreateContainerFactoryBootstrapFile.cs

@@ -14,13 +14,13 @@ namespace Microsoft.VisualStudio.Composition.AppHost
     public class CreateContainerFactoryBootstrapFile : Microsoft.Build.Utilities.Task
     {
         [Required]
-        public string BootstrapFile { get; set; }
+        public string BootstrapFile { get; set; } = null!;
 
         [Required]
-        public string CompositionCacheFile { get; set; }
+        public string CompositionCacheFile { get; set; } = null!;
 
         [Required]
-        public string RootNamespace { get; set; }
+        public string RootNamespace { get; set; } = null!;
 
         public override bool Execute()
         {

src/Microsoft.VisualStudio.Composition.AppHost/Microsoft.VisualStudio.Composition.AppHost.csproj

@@ -16,5 +16,6 @@
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="Nerdbank.MSBuildExtension" Version="0.1.17-beta" PrivateAssets="all" />
+    <PackageReference Include="Nullable" Version="1.3.0" PrivateAssets="all" />
   </ItemGroup>
 </Project>

src/Microsoft.VisualStudio.Composition/ArrayRental`1.cs

@@ -15,8 +15,8 @@ internal static class ArrayRental<T>
 
         internal static Rental<T[]> Get(int length)
         {
-            Stack<T[]> stack;
-            if (!Arrays.Value.TryGetValue(length, out stack))
+            Stack<T[]>? stack;
+            if (!Arrays.Value!.TryGetValue(length, out stack))
             {
                 Arrays.Value.Add(length, stack = new Stack<T[]>());
             }

src/Microsoft.VisualStudio.Composition/ByValueEquality+AssemblyNameComparer.cs

@@ -28,16 +28,16 @@ internal AssemblyNameComparer(bool fastCheck = true)
                 this.fastCheck = fastCheck;
             }
 
-            public bool Equals(AssemblyName x, AssemblyName y)
+            public bool Equals(AssemblyName? x, AssemblyName? y)
             {
-                if (x == null ^ y == null)
+                if (x is null && y is null)
                 {
-                    return false;
+                    return true;
                 }
 
-                if (x == null)
+                if (x is null || y is null)
                 {
-                    return true;
+                    return false;
                 }
 
                 // If fast check is enabled, we can compare the code bases
@@ -51,29 +51,26 @@ public bool Equals(AssemblyName x, AssemblyName y)
                 // compare the PublicKeys first, but then fall back to GetPublicKeyToken(), which
                 // will generate a public key token for the AssemblyName that has a public key and
                 // return the public key token for the other AssemblyName.
-                byte[] xPublicKey = x.GetPublicKey();
-                byte[] yPublicKey = y.GetPublicKey();
+                byte[]? xPublicKey = x.GetPublicKey();
+                byte[]? yPublicKey = y.GetPublicKey();
 
                 // Testing on FullName is horrifically slow.
                 // So test directly on its components instead.
                 if (xPublicKey != null && yPublicKey != null)
                 {
                     return x.Name == y.Name
-                        && x.Version.Equals(y.Version)
+                        && Equals(x.Version, y.Version)
                         && string.Equals(x.CultureName, y.CultureName)
                         && ByValueEquality.Buffer.Equals(xPublicKey, yPublicKey);
                 }
 
                 return x.Name == y.Name
-                    && x.Version.Equals(y.Version)
+                    && Equals(x.Version, y.Version)
                     && string.Equals(x.CultureName, y.CultureName)
                     && ByValueEquality.Buffer.Equals(x.GetPublicKeyToken(), y.GetPublicKeyToken());
             }
 
-            public int GetHashCode(AssemblyName obj)
-            {
-                return obj.Name.GetHashCode();
-            }
+            public int GetHashCode(AssemblyName obj) => obj.Name?.GetHashCode() ?? 0;
         }
     }
 }

src/Microsoft.VisualStudio.Composition/ByValueEquality+BufferComparer.cs

@@ -20,14 +20,14 @@ private BufferComparer()
             {
             }
 
-            public bool Equals(byte[] x, byte[] y)
+            public bool Equals(byte[]? x, byte[]? y)
             {
                 if (x == y)
                 {
                     return true;
                 }
 
-                if (x == null ^ y == null)
+                if (x is null || y is null)
                 {
                     return false;
                 }