feat(csharp): enable nullable reference types (#1246)

This allows users to write safter code by being aware of what is nullable
and what is not. This does not affect the ABI of the libraries, making them
compatible with previous assemblies -- since this is merely additional
metadata in the assembly that enables new compiler warnings.

packages/@jsii/dotnet-analyzers/src/Amazon.JSII.Analyzers.UnitTests/Amazon.JSII.Analyzers.UnitTests.csproj

@@ -4,6 +4,9 @@
     <TargetFramework>netcoreapp3.1</TargetFramework>
     <IsPackable>false</IsPackable>
     <AssemblyName>Amazon.JSII.Analyzers.UnitTests</AssemblyName>
+
+    <Nullable>enable</Nullable>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
 
   <ItemGroup>

packages/@jsii/dotnet-analyzers/src/Amazon.JSII.Analyzers.UnitTests/Helpers/DiagnosticVerifier.Helper.cs

@@ -34,7 +34,7 @@ public abstract partial class DiagnosticVerifier
         /// <param name="language">The language the source classes are in</param>
         /// <param name="analyzer">The analyzer to be run on the sources</param>
         /// <returns>An IEnumerable of Diagnostics that surfaced in the source code, sorted by Location</returns>
-        private static Diagnostic[] GetSortedDiagnostics(string[] sources, string language, DiagnosticAnalyzer analyzer)
+        private static Diagnostic[] GetSortedDiagnostics(string[] sources, string language, DiagnosticAnalyzer? analyzer)
         {
             return GetSortedDiagnosticsFromDocuments(analyzer, GetDocuments(sources, language));
         }
@@ -46,7 +46,7 @@ private static Diagnostic[] GetSortedDiagnostics(string[] sources, string langua
         /// <param name="analyzer">The analyzer to run on the documents</param>
         /// <param name="documents">The Documents that the analyzer will be run on</param>
         /// <returns>An IEnumerable of Diagnostics that surfaced in the source code, sorted by Location</returns>
-        protected static Diagnostic[] GetSortedDiagnosticsFromDocuments(DiagnosticAnalyzer analyzer, Document[] documents)
+        protected static Diagnostic[] GetSortedDiagnosticsFromDocuments(DiagnosticAnalyzer? analyzer, Document[] documents)
         {
             var projects = new HashSet<Project>();
             foreach (var document in documents)
@@ -162,7 +162,7 @@ private static Project CreateProject(string[] sources, string language = Languag
                 solution = solution.AddDocument(documentId, newFileName, SourceText.From(source));
                 count++;
             }
-            return solution.GetProject(projectId);
+            return solution.GetProject(projectId)!;
         }
         #endregion
     }

packages/@jsii/dotnet-analyzers/src/Amazon.JSII.Analyzers.UnitTests/Verifiers/DiagnosticVerifier.cs

@@ -16,15 +16,15 @@ public abstract partial class DiagnosticVerifier
         /// <summary>
         /// Get the CSharp analyzer being tested - to be implemented in non-abstract class
         /// </summary>
-        protected virtual DiagnosticAnalyzer GetCSharpDiagnosticAnalyzer()
+        protected virtual DiagnosticAnalyzer? GetCSharpDiagnosticAnalyzer()
         {
             return null;
         }
 
         /// <summary>
         /// Get the Visual Basic analyzer being tested (C#) - to be implemented in non-abstract class
         /// </summary>
-        protected virtual DiagnosticAnalyzer GetBasicDiagnosticAnalyzer()
+        protected virtual DiagnosticAnalyzer? GetBasicDiagnosticAnalyzer()
         {
             return null;
         }
@@ -84,7 +84,7 @@ protected void VerifyBasicDiagnostic(string[] sources, params DiagnosticResult[]
         /// <param name="language">The language of the classes represented by the source strings</param>
         /// <param name="analyzer">The analyzer to be run on the source code</param>
         /// <param name="expected">DiagnosticResults that should appear after the analyzer is run on the sources</param>
-        private void VerifyDiagnostics(string[] sources, string language, DiagnosticAnalyzer analyzer, params DiagnosticResult[] expected)
+        private void VerifyDiagnostics(string[] sources, string language, DiagnosticAnalyzer? analyzer, params DiagnosticResult[] expected)
         {
             var diagnostics = GetSortedDiagnostics(sources, language, analyzer);
             VerifyDiagnosticResults(diagnostics, analyzer, expected);
@@ -100,7 +100,7 @@ private void VerifyDiagnostics(string[] sources, string language, DiagnosticAnal
         /// <param name="actualResults">The Diagnostics found by the compiler after running the analyzer on the source code</param>
         /// <param name="analyzer">The analyzer that was being run on the sources</param>
         /// <param name="expectedResults">Diagnostic Results that should have appeared in the code</param>
-        private static void VerifyDiagnosticResults(IEnumerable<Diagnostic> actualResults, DiagnosticAnalyzer analyzer, params DiagnosticResult[] expectedResults)
+        private static void VerifyDiagnosticResults(IEnumerable<Diagnostic> actualResults, DiagnosticAnalyzer? analyzer, params DiagnosticResult[] expectedResults)
         {
             int expectedCount = expectedResults.Count();
             int actualCount = actualResults.Count();
@@ -176,7 +176,7 @@ private static void VerifyDiagnosticResults(IEnumerable<Diagnostic> actualResult
         /// <param name="diagnostic">The diagnostic that was found in the code</param>
         /// <param name="actual">The Location of the Diagnostic found in the code</param>
         /// <param name="expected">The DiagnosticResultLocation that should have been found</param>
-        private static void VerifyDiagnosticLocation(DiagnosticAnalyzer analyzer, Diagnostic diagnostic, Location actual, DiagnosticResultLocation expected)
+        private static void VerifyDiagnosticLocation(DiagnosticAnalyzer? analyzer, Diagnostic diagnostic, Location actual, DiagnosticResultLocation expected)
         {
             var actualSpan = actual.GetLineSpan();
 
@@ -217,15 +217,19 @@ private static void VerifyDiagnosticLocation(DiagnosticAnalyzer analyzer, Diagno
         /// <param name="analyzer">The analyzer that this verifier tests</param>
         /// <param name="diagnostics">The Diagnostics to be formatted</param>
         /// <returns>The Diagnostics formatted as a string</returns>
-        private static string FormatDiagnostics(DiagnosticAnalyzer analyzer, params Diagnostic[] diagnostics)
+        private static string FormatDiagnostics(DiagnosticAnalyzer? analyzer, params Diagnostic[] diagnostics)
         {
             var builder = new StringBuilder();
             for (int i = 0; i < diagnostics.Length; ++i)
             {
                 builder.AppendLine("// " + diagnostics[i].ToString());
 
-                var analyzerType = analyzer.GetType();
-                var rules = analyzer.SupportedDiagnostics;
+                var analyzerType = analyzer?.GetType();
+                if (analyzerType == null)
+                {
+                    continue;
+                }
+                var rules = analyzer!.SupportedDiagnostics;
 
                 foreach (var rule in rules)
                 {

packages/@jsii/dotnet-analyzers/src/Amazon.JSII.Analyzers/JsiiOptionalAnalyzer.cs

@@ -105,6 +105,10 @@ private static void AnalyzeNode(SyntaxNodeAnalysisContext context)
         /// <returns>true if the TypeInfo is related to a Jsii class, false otherwise</returns>
         private static bool IsJsiiClass(TypeInfo typeInfo)
         {
+            if (typeInfo.Type == null)
+            {
+                return false;
+            }
             var typeAttributes = typeInfo.Type.GetAttributes().ToArray();
             return typeAttributes.Any(a => a.AttributeClass.Name == "JsiiClassAttribute");
         }
@@ -119,6 +123,10 @@ private static bool IsJsiiClass(TypeInfo typeInfo)
         /// <returns>true if the TypeInfo is related to a Jsii datatype, false otherwise</returns>
         private static bool IsJsiiDatatype(TypeInfo typeInfo)
         {
+            if (typeInfo.Type == null)
+            {
+                return false;
+            }
             var typeAttributes = typeInfo.Type.GetAttributes().ToArray();
             return typeAttributes.Any(a => a.AttributeClass.Name == "JsiiByValueAttribute");
         }

packages/@jsii/dotnet-jsonmodel/src/Amazon.JSII.JsonModel.UnitTests/Amazon.JSII.JsonModel.UnitTests.csproj

@@ -5,6 +5,9 @@
     <IsPackable>false</IsPackable>
     <AssemblyName>Amazon.JSII.JsonModel.UnitTests</AssemblyName>
     <RootNamespace>Amazon.JSII.JsonModel.UnitTests</RootNamespace>
+
+    <Nullable>enable</Nullable>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
 
   <ItemGroup>

packages/@jsii/dotnet-jsonmodel/src/Amazon.JSII.JsonModel.UnitTests/Spec/AssemblyTests.cs

@@ -107,7 +107,9 @@ public void ShouldThrowOnMissingName()
             {
                 Assert.Throws<ArgumentNullException>(() => new Assembly
                 (
+#pragma warning disable CS8625
                     name: null,
+#pragma warning restore CS8625
                     description: "",
                     homepage: "",
                     repository: new Assembly.AssemblyRepository(type: "", url: ""),
@@ -140,7 +142,9 @@ public void ShouldThrowOnMissingVersion()
                     repository: new Assembly.AssemblyRepository(type: "", url: ""),
                     author: new Person(name: "", roles: new string[] { }),
                     fingerprint: "",
+#pragma warning disable CS8625
                     version: null,
+#pragma warning restore CS8625
                     license: "",
                     targets: new AssemblyTargets(new AssemblyTargets.DotNetTarget(
                         @namespace: "Dot.Net.Namespace",
@@ -375,7 +379,7 @@ public void ShouldDeserializeAllMembers()
                 Assert.Empty(actual.Types);
                 Assert.Empty(actual.Dependencies);
                 Assert.Empty(actual.Bundled);
-                Assert.Equal("hello", actual.Docs.Summary);
+                Assert.Equal("hello", actual.Docs?.Summary);
             }
 
             [Fact(DisplayName = Prefix + nameof(ShouldDeserializeAllMembersWithNoTypes))]
@@ -411,7 +415,7 @@ public void ShouldDeserializeAllMembersWithNoTypes()
                 Assert.Null(actual.Types);
                 Assert.Empty(actual.Dependencies);
                 Assert.Empty(actual.Bundled);
-                Assert.Equal("hello", actual.Docs.Summary);
+                Assert.Equal("hello", actual.Docs?.Summary);
             }
 
 
@@ -455,19 +459,19 @@ public void ShouldDeserializeAllMembersWithDotNetTarget()
                 Assert.Equal("jsii/0.9.0", actual.Schema, ignoreLineEndingDifferences: true);
                 Assert.Equal("myName", actual.Name, ignoreLineEndingDifferences: true);
 
-                AssemblyTargets.DotNetTarget dotNetTarget = actual.Targets.DotNet;
+                AssemblyTargets.DotNetTarget? dotNetTarget = actual.Targets?.DotNet;
                 Assert.NotNull(dotNetTarget);
-                Assert.Equal("Dot.Net.Namespace", dotNetTarget.Namespace);
-                Assert.Equal("Dot.Net.PackageId", dotNetTarget.PackageId);
-                Assert.True(dotNetTarget.SignAssembly);
-                Assert.Equal("key.snk", dotNetTarget.AssemblyOriginatorKeyFile);
-                Assert.Equal("http://www.example.com/icon.png", dotNetTarget.IconUrl);
+                Assert.Equal("Dot.Net.Namespace", dotNetTarget?.Namespace);
+                Assert.Equal("Dot.Net.PackageId", dotNetTarget?.PackageId);
+                Assert.True(dotNetTarget?.SignAssembly);
+                Assert.Equal("key.snk", dotNetTarget?.AssemblyOriginatorKeyFile);
+                Assert.Equal("http://www.example.com/icon.png", dotNetTarget?.IconUrl);
 
                 Assert.Equal("myVersion", actual.Version, ignoreLineEndingDifferences: true);
                 Assert.Empty(actual.Types);
                 Assert.Empty(actual.Dependencies);
                 Assert.Empty(actual.Bundled);
-                Assert.Equal("hello", actual.Docs.Summary);
+                Assert.Equal("hello", actual.Docs?.Summary);
             }
 
             [Fact(DisplayName = Prefix + nameof(ShouldThrowOnMissingName))]

packages/@jsii/dotnet-jsonmodel/src/Amazon.JSII.JsonModel.UnitTests/Spec/ClassTypeTests.cs

@@ -1,4 +1,4 @@
-using Amazon.JSII.JsonModel.Spec;
+using Amazon.JSII.JsonModel.Spec;
 using Newtonsoft.Json;
 using System;
 using System.Linq;
@@ -56,7 +56,9 @@ public void ShouldThrowOnMissingFullyQualifiedName()
             {
                 Assert.Throws<ArgumentNullException>(() => new ClassType
                 (
+#pragma warning disable CS8625
                     fullyQualifiedName: null,
+#pragma warning restore CS8625
                     assembly: "myModule",
                     name: "myName",
                     @namespace: "myNamespace",
@@ -76,7 +78,9 @@ public void ShouldThrowOnMissingAssembly()
                 Assert.Throws<ArgumentNullException>(() => new ClassType
                 (
                     fullyQualifiedName: "myFqn",
+#pragma warning disable CS8625
                     assembly: null,
+#pragma warning restore CS8625
                     name: "myName",
                     @namespace: "myNamespace",
                     isAbstract: true,
@@ -96,7 +100,9 @@ public void ShouldThrowOnMissingName()
                 (
                     fullyQualifiedName: "myFqn",
                     assembly: "myModule",
+#pragma warning disable CS8625
                     name: null,
+#pragma warning restore CS8625
                     @namespace: "myNamespace",
                     isAbstract: true,
                     docs: new Docs(),
@@ -388,7 +394,7 @@ public void ShouldDeserializeAllMembers()
                 Assert.Equal("myName", actual.Name, ignoreLineEndingDifferences: true);
                 Assert.Equal("myNamespace", actual.Namespace, ignoreLineEndingDifferences: true);
                 Assert.Equal(TypeKind.Class, actual.Kind);
-                Assert.Equal("hello", actual.Docs.Summary);
+                Assert.Equal("hello", actual.Docs?.Summary);
             }
 
             [Fact(DisplayName = Prefix + nameof(ShouldThrowOnMissingFullyQualifiedName))]
@@ -623,8 +629,8 @@ public void DeserializesAsyncMethod()
 
                 ClassType actual = JsonConvert.DeserializeObject<ClassType>(json);
 
-                Assert.True(actual.Methods.Length == 1);
-                Assert.True(actual.Methods[0]?.IsAsync);
+                Assert.Equal(1, actual.Methods?.Length);
+                Assert.True(actual.Methods?[0]?.IsAsync);
             }
         }
     }

packages/@jsii/dotnet-jsonmodel/src/Amazon.JSII.JsonModel.UnitTests/Spec/CollectionKindTests.cs

@@ -1,4 +1,4 @@
-using Amazon.JSII.JsonModel.Spec;
+using Amazon.JSII.JsonModel.Spec;
 using Newtonsoft.Json;
 using System;
 using Xunit;
@@ -41,7 +41,9 @@ public void ShouldDeserialize(string kind, CollectionKind expected)
             [Fact(DisplayName = Prefix + nameof(ShouldThrowOnNull))]
             public void ShouldThrowOnNull()
             {
+#pragma warning disable CS8625
                 Assert.Throws<ArgumentNullException>(() => JsonConvert.DeserializeObject<CollectionKind>(null));
+#pragma warning restore CS8625
             }
         }
     }

packages/@jsii/dotnet-jsonmodel/src/Amazon.JSII.JsonModel.UnitTests/Spec/CollectionTypeReferenceTests.cs

@@ -1,4 +1,4 @@
-using Amazon.JSII.JsonModel.Spec;
+using Amazon.JSII.JsonModel.Spec;
 using Newtonsoft.Json;
 using System;
 using Xunit;
@@ -36,7 +36,9 @@ public void ShouldSerializeAllMembers()
             [Fact(DisplayName = Prefix + nameof(ShouldThrowOnMissingElementType))]
             public void ShouldThrowOnMissingElementType()
             {
+#pragma warning disable CS8625
                 Assert.Throws<ArgumentNullException>(() => new CollectionTypeReference(CollectionKind.Array, null));
+#pragma warning restore CS8625
             }
         }
 

packages/@jsii/dotnet-jsonmodel/src/Amazon.JSII.JsonModel.UnitTests/Spec/EnumMemberTests.cs

@@ -1,4 +1,4 @@
-using Amazon.JSII.JsonModel.Spec;
+using Amazon.JSII.JsonModel.Spec;
 using Newtonsoft.Json;
 using System;
 using Xunit;
@@ -30,7 +30,9 @@ public void ShouldSerializeAllMembers()
             [Fact(DisplayName = Prefix + nameof(ShouldThrowOnMissingName))]
             public void ShouldThrowOnMissingName()
             {
+#pragma warning disable CS8625
                 Assert.Throws<ArgumentNullException>(() => new EnumMember(null, new Docs()));
+#pragma warning restore CS8625
             }
 
             [Fact(DisplayName = Prefix + nameof(ShouldNotSerializeMissingDocs))]
@@ -61,8 +63,8 @@ public void ShouldDeserializeAllMembers()
 
                 EnumMember actual = JsonConvert.DeserializeObject<EnumMember>(json);
 
-                Assert.Equal("myName", actual.Name, ignoreLineEndingDifferences: true);
-                Assert.Equal("hello", actual.Docs.Summary);
+                Assert.Equal("myName", actual?.Name, ignoreLineEndingDifferences: true);
+                Assert.Equal("hello", actual?.Docs?.Summary);
             }
 
             [Fact(DisplayName = Prefix + nameof(ShouldThrowOnMissingName))]

packages/@jsii/dotnet-jsonmodel/src/Amazon.JSII.JsonModel/Amazon.JSII.JsonModel.csproj

@@ -6,6 +6,9 @@
     <PackageId>Amazon.JSII.JsonModel</PackageId>
     <Title>.NET JsonModel for JSII</Title>
     <PackageIcon>icon.png</PackageIcon>
+
+    <Nullable>enable</Nullable>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
 
   <ItemGroup>

packages/@jsii/dotnet-jsonmodel/src/Amazon.JSII.JsonModel/Api/Callback.cs

@@ -10,10 +10,10 @@ public class Callback
         public Callback
         (
             string callbackId,
-            string cookie = null,
-            InvokeRequest invoke = null,
-            GetRequest get = null,
-            SetRequest set = null
+            string? cookie = null,
+            InvokeRequest? invoke = null,
+            GetRequest? get = null,
+            SetRequest? set = null
         )
         {
             CallbackId = callbackId ?? throw new ArgumentNullException(nameof(callbackId));
@@ -27,15 +27,15 @@ public Callback
         public string CallbackId { get; }
 
         [JsonProperty("cookie", NullValueHandling = NullValueHandling.Ignore)]
-        public string Cookie { get; }
+        public string? Cookie { get; }
 
         [JsonProperty("invoke", NullValueHandling = NullValueHandling.Ignore)]
-        public InvokeRequest Invoke { get; }
+        public InvokeRequest? Invoke { get; }
 
         [JsonProperty("get", NullValueHandling = NullValueHandling.Ignore)]
-        public GetRequest Get { get; }
+        public GetRequest? Get { get; }
 
         [JsonProperty("set", NullValueHandling = NullValueHandling.Ignore)]
-        public SetRequest Set { get; }
+        public SetRequest? Set { get; }
     }
 }

packages/@jsii/dotnet-jsonmodel/src/Amazon.JSII.JsonModel/Api/Override.cs

@@ -7,9 +7,9 @@ public class Override
     {
         public Override
         (
-            string method = null,
-            string property = null,
-            string cookie = null
+            string? method = null,
+            string? property = null,
+            string? cookie = null
         )
         {
             Method = method;
@@ -18,12 +18,12 @@ public Override
         }
 
         [JsonProperty("method", NullValueHandling = NullValueHandling.Ignore)]
-        public string Method { get; }
+        public string? Method { get; }
 
         [JsonProperty("property", NullValueHandling = NullValueHandling.Ignore)]
-        public string Property { get; }
+        public string? Property { get; }
 
         [JsonProperty("cookie", NullValueHandling = NullValueHandling.Ignore)]
-        public string Cookie { get; }
+        public string? Cookie { get; }
     }
 }