.NET: Add nullable annotations to Protobuf library

csharp/README.md

@@ -23,6 +23,7 @@ The runtime library is built as a portable class library, supporting:
 - Windows Phone Silverlight 8
 - Windows Phone 8.1
 - .NET Core
+- .NET 5
 
 You should be able to use Protocol Buffers in Visual Studio 2012 and
 all later versions. This includes all code generated by `protoc`,
@@ -31,15 +32,15 @@ which only uses features from C# 3 and earlier.
 Building
 ========
 
-Open the `src/Google.Protobuf.sln` solution in Visual Studio 2017 or
+Open the `src/Google.Protobuf.sln` solution in Visual Studio 2022 or
 later.
 
 Although *users* of this project are only expected to have Visual
 Studio 2012 or later, *developers* of the library are required to
-have Visual Studio 2017 or later, as the library uses C# 6 features
-in its implementation, as well as the new Visual Studio 2017 csproj
-format. These features have no impact when using the compiled code -
-they're only relevant when building the `Google.Protobuf` assembly.
+have Visual Studio 2022 or later, as the library uses C# 10 features
+in its implementation and runs tests under .NET 6. These features
+have no impact when using the compiled code - they're only relevant
+when building the `Google.Protobuf` assembly.
 
 In order to run and debug the AddressBook example in the IDE, you must
 install the optional component, ".Net Core 1.0 - 1.1 development tools

csharp/compatibility_tests/v3.0.0/src/Google.Protobuf.Test/Google.Protobuf.Test.csproj

@@ -6,6 +6,7 @@
     <AssemblyOriginatorKeyFile>../../keys/Google.Protobuf.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>true</SignAssembly>
     <IsPackable>False</IsPackable>
+    <LangVersion>8.0</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>

csharp/src/AddressBook/AddPerson.cs

@@ -45,13 +45,13 @@ private static Person PromptForAddress(TextReader input, TextWriter output)
             Person person = new Person();
 
             output.Write("Enter person ID: ");
-            person.Id = int.Parse(input.ReadLine());
+            person.Id = int.Parse(input.ReadLine() ?? string.Empty);
 
             output.Write("Enter name: ");
             person.Name = input.ReadLine();
 
             output.Write("Enter email address (blank for none): ");
-            string email = input.ReadLine();
+            string email = input.ReadLine() ?? string.Empty;
             if (email.Length > 0)
             {
                 person.Email = email;
@@ -60,7 +60,7 @@ private static Person PromptForAddress(TextReader input, TextWriter output)
             while (true)
             {
                 output.Write("Enter a phone number (or leave blank to finish): ");
-                string number = input.ReadLine();
+                string number = input.ReadLine() ?? string.Empty;
                 if (number.Length == 0)
                 {
                     break;
@@ -69,7 +69,7 @@ private static Person PromptForAddress(TextReader input, TextWriter output)
                 Person.Types.PhoneNumber phoneNumber = new Person.Types.PhoneNumber { Number = number };
 
                 output.Write("Is this a mobile, home, or work phone? ");
-                String type = input.ReadLine();
+                String type = input.ReadLine() ?? string.Empty;
                 switch (type)
                 {
                     case "mobile":

csharp/src/Backup/Google.Protobuf.sln

@@ -0,0 +1,60 @@
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio 15
+VisualStudioVersion = 15.0.26114.2
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "AddressBook", "AddressBook\AddressBook.csproj", "{AFB63919-1E05-43B4-802A-8FB8C9B2F463}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Google.Protobuf", "Google.Protobuf\Google.Protobuf.csproj", "{9B576380-726D-4142-8238-60A43AB0E35A}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Google.Protobuf.Test", "Google.Protobuf.Test\Google.Protobuf.Test.csproj", "{580EB013-D3C7-4578-B845-015F4A3B0591}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Google.Protobuf.Conformance", "Google.Protobuf.Conformance\Google.Protobuf.Conformance.csproj", "{DDDC055B-E185-4181-BAB0-072F0F984569}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Google.Protobuf.JsonDump", "Google.Protobuf.JsonDump\Google.Protobuf.JsonDump.csproj", "{9695E08F-9829-497D-B95C-B38F28D48690}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Google.Protobuf.Benchmarks", "Google.Protobuf.Benchmarks\Google.Protobuf.Benchmarks.csproj", "{D25E4804-4DEA-45AB-9F8C-BA4DBD8E5A07}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Google.Protobuf.Test.TestProtos", "Google.Protobuf.Test.TestProtos\Google.Protobuf.Test.TestProtos.csproj", "{ADF24BEB-A318-4530-8448-356B72B820EA}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{AFB63919-1E05-43B4-802A-8FB8C9B2F463}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{AFB63919-1E05-43B4-802A-8FB8C9B2F463}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{AFB63919-1E05-43B4-802A-8FB8C9B2F463}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{AFB63919-1E05-43B4-802A-8FB8C9B2F463}.Release|Any CPU.Build.0 = Release|Any CPU
+		{9B576380-726D-4142-8238-60A43AB0E35A}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{9B576380-726D-4142-8238-60A43AB0E35A}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{9B576380-726D-4142-8238-60A43AB0E35A}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{9B576380-726D-4142-8238-60A43AB0E35A}.Release|Any CPU.Build.0 = Release|Any CPU
+		{580EB013-D3C7-4578-B845-015F4A3B0591}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{580EB013-D3C7-4578-B845-015F4A3B0591}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{580EB013-D3C7-4578-B845-015F4A3B0591}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{580EB013-D3C7-4578-B845-015F4A3B0591}.Release|Any CPU.Build.0 = Release|Any CPU
+		{DDDC055B-E185-4181-BAB0-072F0F984569}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{DDDC055B-E185-4181-BAB0-072F0F984569}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{DDDC055B-E185-4181-BAB0-072F0F984569}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{DDDC055B-E185-4181-BAB0-072F0F984569}.Release|Any CPU.Build.0 = Release|Any CPU
+		{9695E08F-9829-497D-B95C-B38F28D48690}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{9695E08F-9829-497D-B95C-B38F28D48690}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{9695E08F-9829-497D-B95C-B38F28D48690}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{9695E08F-9829-497D-B95C-B38F28D48690}.Release|Any CPU.Build.0 = Release|Any CPU
+		{D25E4804-4DEA-45AB-9F8C-BA4DBD8E5A07}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{D25E4804-4DEA-45AB-9F8C-BA4DBD8E5A07}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{D25E4804-4DEA-45AB-9F8C-BA4DBD8E5A07}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{D25E4804-4DEA-45AB-9F8C-BA4DBD8E5A07}.Release|Any CPU.Build.0 = Release|Any CPU
+		{ADF24BEB-A318-4530-8448-356B72B820EA}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{ADF24BEB-A318-4530-8448-356B72B820EA}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{ADF24BEB-A318-4530-8448-356B72B820EA}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{ADF24BEB-A318-4530-8448-356B72B820EA}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {7B06C87B-83E1-4F5F-A0DD-6E9AFAC03DAC}
+	EndGlobalSection
+EndGlobal

csharp/src/Directory.Build.props

@@ -0,0 +1,11 @@
+<Project>
+
+  <PropertyGroup>
+    <!-- C# 7.3+ is required for Span/BufferWriter/ReadOnlySequence -->
+    <!-- v10 is compatible with Visual Studio 2022+ -->
+    <LangVersion>10.0</LangVersion>
+
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

csharp/src/Google.Protobuf.Benchmarks/BenchmarkDatasetConfig.cs

@@ -49,14 +49,14 @@ public class BenchmarkDatasetConfig
             typeof(GoogleMessageBenchmark).Assembly.GetTypes()
                 .Where(t => typeof(IMessage).IsAssignableFrom(t))
                 .ToDictionary(
-                    t => ((MessageDescriptor) t.GetProperty("Descriptor", BindingFlags.Static | BindingFlags.Public).GetValue(null)).FullName,
-                    t => ((MessageParser) t.GetProperty("Parser", BindingFlags.Static | BindingFlags.Public).GetValue(null)));
+                    t => ((MessageDescriptor) t.GetProperty("Descriptor", BindingFlags.Static | BindingFlags.Public)!.GetValue(null)!).FullName,
+                    t => ((MessageParser) t.GetProperty("Parser", BindingFlags.Static | BindingFlags.Public)!.GetValue(null)!));
 
         public MessageParser Parser { get; }
         public List<byte[]> Payloads { get; }
         public string Name { get; }
 
-        public BenchmarkDatasetConfig(string resource, string shortName = null)
+        public BenchmarkDatasetConfig(string resource, string? shortName = null)
         {
             var data = LoadData(resource);
             var dataset = BenchmarkDataset.Parser.ParseFrom(data);

csharp/src/Google.Protobuf.Benchmarks/ByteStringBenchmark.cs

@@ -32,6 +32,8 @@
 
 using BenchmarkDotNet.Attributes;
 
+#nullable disable
+
 namespace Google.Protobuf.Benchmarks
 {
     /// <summary>
@@ -60,7 +62,7 @@ public void GlobalSetup()
         [Benchmark]
         public ByteString CopyFrom()
         {
-            return ByteString.CopyFrom(byteBuffer);
+            return ByteString.CopyFrom(byteBuffer!);
         }
 
         [Benchmark]

csharp/src/Google.Protobuf.Benchmarks/GoogleMessageBenchmark.cs

@@ -58,34 +58,34 @@ public class GoogleMessageBenchmark
         };
 
         [ParamsSource(nameof(DatasetConfigurations))]
-        public BenchmarkDatasetConfig Dataset { get; set; }
+        public BenchmarkDatasetConfig? Dataset { get; set; }
 
-        private MessageParser parser;
+        private MessageParser? parser;
         /// <summary>
         /// Each data set can contain multiple messages in a single file.
         /// Each "write" operation should write each message in turn, and each "parse"
         /// operation should parse each message in turn.
         /// </summary>
-        private List<SubTest> subTests;
+        private List<SubTest>? subTests;
 
         [GlobalSetup]
         public void GlobalSetup()
         {
-            parser = Dataset.Parser;
+            parser = Dataset!.Parser;
             subTests = Dataset.Payloads.Select(p => new SubTest(p, parser.ParseFrom(p))).ToList();
         }
 
         [Benchmark]
-        public void WriteToStream() => subTests.ForEach(item => item.WriteToStream());
+        public void WriteToStream() => subTests!.ForEach(item => item.WriteToStream());
 
         [Benchmark]
-        public void ToByteArray() => subTests.ForEach(item => item.ToByteArray());
+        public void ToByteArray() => subTests!.ForEach(item => item.ToByteArray());
 
         [Benchmark]
-        public void ParseFromByteArray() => subTests.ForEach(item => item.ParseFromByteArray(parser));
+        public void ParseFromByteArray() => subTests!.ForEach(item => item.ParseFromByteArray(parser!));
 
         [Benchmark]
-        public void ParseFromStream() => subTests.ForEach(item => item.ParseFromStream(parser));
+        public void ParseFromStream() => subTests!.ForEach(item => item.ParseFromStream(parser!));
 
         private class SubTest
         {