Add integration with the new required keyword

Closes #132

CliFx.Analyzers.Tests/CliFx.Analyzers.Tests.csproj

@@ -9,7 +9,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Basic.Reference.Assemblies" Version="1.4.1" />
+    <PackageReference Include="Basic.Reference.Assemblies.Net70" Version="1.4.1" />
     <PackageReference Include="GitHubActionsTestLogger" Version="2.0.1" PrivateAssets="all" />
     <PackageReference Include="FluentAssertions" Version="6.8.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.4.0" />

CliFx.Analyzers.Tests/OptionMustBeRequiredIfPropertyRequiredAnalyzerSpecs.cs

@@ -0,0 +1,114 @@
+using CliFx.Analyzers.Tests.Utils;
+using Microsoft.CodeAnalysis.Diagnostics;
+using Xunit;
+
+namespace CliFx.Analyzers.Tests;
+
+public class OptionMustBeRequiredIfPropertyRequiredAnalyzerSpecs
+{
+    private static DiagnosticAnalyzer Analyzer { get; } = new OptionMustBeRequiredIfPropertyRequiredAnalyzer();
+
+    [Fact]
+    public void Analyzer_reports_an_error_if_a_non_required_option_is_bound_to_a_required_property()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                [CommandOption('f', IsRequired = false)]
+                public required string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().ProduceDiagnostics(code);
+    }
+
+    [Fact]
+    public void Analyzer_does_not_report_an_error_if_a_required_option_is_bound_to_a_required_property()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                [CommandOption('f', IsRequired = true)]
+                public required string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().NotProduceDiagnostics(code);
+    }
+
+    [Fact]
+    public void Analyzer_does_not_report_an_error_if_a_non_required_option_is_bound_to_an_unannotated_property()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                [CommandOption('f', IsRequired = false)]
+                public string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().NotProduceDiagnostics(code);
+    }
+
+    [Fact]
+    public void Analyzer_does_not_report_an_error_if_a_required_option_is_bound_to_an_unannotated_property()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                [CommandOption('f', IsRequired = true)]
+                public string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().NotProduceDiagnostics(code);
+    }
+
+    [Fact]
+    public void Analyzer_does_not_report_an_error_on_a_property_that_is_not_an_option()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                public required string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().NotProduceDiagnostics(code);
+    }
+}

CliFx.Analyzers.Tests/ParameterMustBeLastIfNonRequiredAnalyzerSpecs.cs

@@ -18,10 +18,10 @@ public class ParameterMustBeLastIfNonRequiredAnalyzerSpecs
             [Command]
             public class MyCommand : ICommand
             {
-                [CommandParameter(0, Name = "foo", IsRequired = false)]
+                [CommandParameter(0, IsRequired = false)]
                 public string Foo { get; set; }
             
-                [CommandParameter(1, Name = "bar")]
+                [CommandParameter(1)]
                 public string Bar { get; set; }
             
                 public ValueTask ExecuteAsync(IConsole console) => default;
@@ -42,10 +42,10 @@ public class ParameterMustBeLastIfNonRequiredAnalyzerSpecs
             [Command]
             public class MyCommand : ICommand
             {
-                [CommandParameter(0, Name = "foo")]
+                [CommandParameter(0)]
                 public string Foo { get; set; }
             
-                [CommandParameter(1, Name = "bar", IsRequired = false)]
+                [CommandParameter(1, IsRequired = false)]
                 public string Bar { get; set; }
             
                 public ValueTask ExecuteAsync(IConsole console) => default;
@@ -66,10 +66,10 @@ public class ParameterMustBeLastIfNonRequiredAnalyzerSpecs
             [Command]
             public class MyCommand : ICommand
             {
-                [CommandParameter(0, Name = "foo")]
+                [CommandParameter(0)]
                 public string Foo { get; set; }
             
-                [CommandParameter(1, Name = "bar", IsRequired = true)]
+                [CommandParameter(1, IsRequired = true)]
                 public string Bar { get; set; }
             
                 public ValueTask ExecuteAsync(IConsole console) => default;

CliFx.Analyzers.Tests/ParameterMustBeRequiredIfPropertyRequiredAnalyzerSpecs.cs

@@ -0,0 +1,114 @@
+using CliFx.Analyzers.Tests.Utils;
+using Microsoft.CodeAnalysis.Diagnostics;
+using Xunit;
+
+namespace CliFx.Analyzers.Tests;
+
+public class ParameterMustBeRequiredIfPropertyRequiredAnalyzerSpecs
+{
+    private static DiagnosticAnalyzer Analyzer { get; } = new ParameterMustBeRequiredIfPropertyRequiredAnalyzer();
+
+    [Fact]
+    public void Analyzer_reports_an_error_if_a_non_required_parameter_is_bound_to_a_required_property()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                [CommandParameter(0, IsRequired = false)]
+                public required string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().ProduceDiagnostics(code);
+    }
+
+    [Fact]
+    public void Analyzer_does_not_report_an_error_if_a_required_parameter_is_bound_to_a_required_property()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                [CommandParameter(0, IsRequired = true)]
+                public required string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().NotProduceDiagnostics(code);
+    }
+
+    [Fact]
+    public void Analyzer_does_not_report_an_error_if_a_non_required_parameter_is_bound_to_an_unannotated_property()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                [CommandParameter(0, IsRequired = false)]
+                public string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().NotProduceDiagnostics(code);
+    }
+
+    [Fact]
+    public void Analyzer_does_not_report_an_error_if_a_required_parameter_is_bound_to_an_unannotated_property()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                [CommandParameter(0, IsRequired = true)]
+                public string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().NotProduceDiagnostics(code);
+    }
+
+    [Fact]
+    public void Analyzer_does_not_report_an_error_on_a_property_that_is_not_a_parameter()
+    {
+        // Arrange
+        // language=cs
+        const string code =
+            """
+            [Command]
+            public class MyCommand : ICommand
+            {
+                public required string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """;
+
+        // Act & assert
+        Analyzer.Should().NotProduceDiagnostics(code);
+    }
+}

CliFx.Analyzers.Tests/Utils/AnalyzerAssertions.cs

@@ -58,8 +58,7 @@ internal class AnalyzerAssertions : ReferenceTypeAssertions<DiagnosticAnalyzer,
         var compilation = CSharpCompilation.Create(
             "CliFxTests_DynamicAssembly_" + Guid.NewGuid(),
             new[] { ast },
-            ReferenceAssemblies
+            Net70.References.All
-                .Net60
                 .Append(MetadataReference.CreateFromFile(typeof(ICommand).Assembly.Location)),
             // DLL to avoid having to define the Main() method
             new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary)

CliFx.Analyzers/ObjectModel/CommandOptionSymbol.cs

@@ -13,6 +13,8 @@ internal partial class CommandOptionSymbol : ICommandMemberSymbol
 
     public char? ShortName { get; }
 
+    public bool? IsRequired { get; }
+
     public ITypeSymbol? ConverterType { get; }
 
     public IReadOnlyList<ITypeSymbol> ValidatorTypes { get; }
@@ -21,12 +23,14 @@ internal partial class CommandOptionSymbol : ICommandMemberSymbol
         IPropertySymbol property,
         string? name,
         char? shortName,
+        bool? isRequired,
         ITypeSymbol? converterType,
         IReadOnlyList<ITypeSymbol> validatorTypes)
     {
         Property = property;
         Name = name;
         ShortName = shortName;
+        IsRequired = isRequired;
         ConverterType = converterType;
         ValidatorTypes = validatorTypes;
     }
@@ -56,6 +60,12 @@ internal partial class CommandOptionSymbol
             .Select(a => a.Value)
             .FirstOrDefault() as char?;
 
+        var isRequired = attribute
+            .NamedArguments
+            .Where(a => a.Key == "IsRequired")
+            .Select(a => a.Value.Value)
+            .FirstOrDefault() as bool?;
+
         var converter = attribute
             .NamedArguments
             .Where(a => a.Key == "Converter")
@@ -71,7 +81,7 @@ internal partial class CommandOptionSymbol
             .Cast<ITypeSymbol>()
             .ToArray();
 
-        return new CommandOptionSymbol(property, name, shortName, converter, validators);
+        return new CommandOptionSymbol(property, name, shortName, isRequired, converter, validators);
     }
 
     public static bool IsOptionProperty(IPropertySymbol property) =>

CliFx.Analyzers/OptionMustBeRequiredIfPropertyRequiredAnalyzer.cs

@@ -0,0 +1,49 @@
+using CliFx.Analyzers.ObjectModel;
+using CliFx.Analyzers.Utils.Extensions;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Diagnostics;
+
+namespace CliFx.Analyzers;
+
+[DiagnosticAnalyzer(LanguageNames.CSharp)]
+public class OptionMustBeRequiredIfPropertyRequiredAnalyzer : AnalyzerBase
+{
+    public OptionMustBeRequiredIfPropertyRequiredAnalyzer()
+        : base(
+            "Options bound to required properties cannot be marked as non-required",
+            "This option cannot be marked as non-required because it's bound to a required property.")
+    {
+    }
+
+    private void Analyze(
+        SyntaxNodeAnalysisContext context,
+        PropertyDeclarationSyntax propertyDeclaration,
+        IPropertySymbol property)
+    {
+        if (property.ContainingType is null)
+            return;
+
+        if (!property.IsRequired)
+            return;
+
+        var option = CommandOptionSymbol.TryResolve(property);
+        if (option is null)
+            return;
+
+        if (option.IsRequired != false)
+            return;
+
+        context.ReportDiagnostic(
+            CreateDiagnostic(
+                propertyDeclaration.Identifier.GetLocation()
+            )
+        );
+    }
+
+    public override void Initialize(AnalysisContext context)
+    {
+        base.Initialize(context);
+        context.HandlePropertyDeclaration(Analyze);
+    }
+}

CliFx.Analyzers/ParameterMustBeRequiredIfPropertyRequiredAnalyzer.cs

@@ -0,0 +1,49 @@
+using CliFx.Analyzers.ObjectModel;
+using CliFx.Analyzers.Utils.Extensions;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Diagnostics;
+
+namespace CliFx.Analyzers;
+
+[DiagnosticAnalyzer(LanguageNames.CSharp)]
+public class ParameterMustBeRequiredIfPropertyRequiredAnalyzer : AnalyzerBase
+{
+    public ParameterMustBeRequiredIfPropertyRequiredAnalyzer()
+        : base(
+            "Parameters bound to required properties cannot be marked as non-required",
+            "This parameter cannot be marked as non-required because it's bound to a required property.")
+    {
+    }
+
+    private void Analyze(
+        SyntaxNodeAnalysisContext context,
+        PropertyDeclarationSyntax propertyDeclaration,
+        IPropertySymbol property)
+    {
+        if (property.ContainingType is null)
+            return;
+
+        if (!property.IsRequired)
+            return;
+
+        var parameter = CommandParameterSymbol.TryResolve(property);
+        if (parameter is null)
+            return;
+
+        if (parameter.IsRequired != false)
+            return;
+
+        context.ReportDiagnostic(
+            CreateDiagnostic(
+                propertyDeclaration.Identifier.GetLocation()
+            )
+        );
+    }
+
+    public override void Initialize(AnalysisContext context)
+    {
+        base.Initialize(context);
+        context.HandlePropertyDeclaration(Analyze);
+    }
+}

CliFx.Demo/Readme.md

@@ -2,4 +2,4 @@
 
 Sample command line interface for managing a library of books.
 
-This demo project showcases basic CliFx functionality such as command routing, argument parsing, autogenerated help text.
+This demo project showcases basic CliFx functionality such as command routing, argument parsing, and autogenerated help text.

CliFx.Tests/CliFx.Tests.csproj

@@ -9,7 +9,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Basic.Reference.Assemblies" Version="1.4.1" />
+    <PackageReference Include="Basic.Reference.Assemblies.Net70" Version="1.4.1" />
     <PackageReference Include="CliWrap" Version="3.5.0" />
     <PackageReference Include="FluentAssertions" Version="6.8.0" />
     <PackageReference Include="GitHubActionsTestLogger" Version="2.0.1" PrivateAssets="all" />

CliFx.Tests/OptionBindingSpecs.cs

@@ -816,4 +816,40 @@ public class OptionBindingSpecs : SpecsBase
         exitCode.Should().NotBe(0);
         stdErr.Should().Contain("expects a single argument, but provided with multiple");
     }
+
+    [Fact]
+    public async Task Option_binding_fails_if_a_required_property_option_has_not_been_provided()
+    {
+        // Arrange
+        var commandType = DynamicCommandBuilder.Compile(
+            // language=cs
+            """
+            [Command]
+            public class Command : ICommand
+            {
+                [CommandOption("foo")]
+                public required string Foo { get; set; }
+
+                public ValueTask ExecuteAsync(IConsole console) => default;
+            }
+            """
+        );
+
+        var application = new CliApplicationBuilder()
+            .AddCommand(commandType)
+            .UseConsole(FakeConsole)
+            .Build();
+
+        // Act
+        var exitCode = await application.RunAsync(
+            Array.Empty<string>(),
+            new Dictionary<string, string>()
+        );
+
+        var stdErr = FakeConsole.ReadErrorString();
+
+        // Assert
+        exitCode.Should().NotBe(0);
+        stdErr.Should().Contain("Missing required option(s)");
+    }
 }

CliFx.Tests/Utils/DynamicCommandBuilder.cs

@@ -61,8 +61,7 @@ internal static class DynamicCommandBuilder
         var compilation = CSharpCompilation.Create(
             "CliFxTests_DynamicAssembly_" + Guid.NewGuid(),
             new[] {ast},
-            ReferenceAssemblies
+            Net70.References.All
-                .Net60
                 .Append(MetadataReference.CreateFromFile(typeof(ICommand).Assembly.Location))
                 .Append(MetadataReference.CreateFromFile(typeof(DynamicCommandBuilder).Assembly.Location)),
             // DLL to avoid having to define the Main() method

CliFx/Attributes/CommandOptionAttribute.cs

@@ -32,6 +32,10 @@ public sealed class CommandOptionAttribute : Attribute
     /// Whether this option is required (default: <c>false</c>).
     /// If an option is required, the user will get an error if they don't set it.
     /// </summary>
+    /// <remarks>
+    /// You can use the <c>required</c> keyword on the property (introduced in C# 11) to implicitly
+    /// set <see cref="IsRequired" /> to <c>true</c>.
+    /// </remarks>
     public bool IsRequired { get; set; }
 
     /// <summary>

CliFx/Schema/OptionSchema.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Reflection;
 using System.Text;
 using CliFx.Attributes;
+using CliFx.Utils.Extensions;
 
 namespace CliFx.Schema;
 
@@ -101,6 +102,7 @@ internal partial class OptionSchema
         // The user may mistakenly specify dashes, thinking it's required, so trim them
         var name = attribute.Name?.TrimStart('-').Trim();
         var environmentVariable = attribute.EnvironmentVariable?.Trim();
+        var isRequired = attribute.IsRequired || property.IsRequired();
         var description = attribute.Description?.Trim();
 
         return new OptionSchema(
@@ -108,7 +110,7 @@ internal partial class OptionSchema
             name,
             attribute.ShortName,
             environmentVariable,
-            attribute.IsRequired,
+            isRequired,
             description,
             attribute.Converter,
             attribute.Validators

CliFx/Schema/ParameterSchema.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Reflection;
 using CliFx.Attributes;
+using CliFx.Utils.Extensions;
 
 namespace CliFx.Schema;
 
@@ -53,13 +54,14 @@ internal partial class ParameterSchema
             return null;
 
         var name = attribute.Name?.Trim() ?? property.Name.ToLowerInvariant();
+        var isRequired = attribute.IsRequired || property.IsRequired();
         var description = attribute.Description?.Trim();
 
         return new ParameterSchema(
             new BindablePropertyDescriptor(property),
             attribute.Order,
             name,
-            attribute.IsRequired,
+            isRequired,
             description,
             attribute.Converter,
             attribute.Validators

CliFx/Utils/Extensions/CollectionExtensions.cs

@@ -1,4 +1,5 @@
-using System.Collections;
+using System;
+using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -37,4 +38,14 @@ internal static class CollectionExtensions
         dictionary
             .Cast<DictionaryEntry>()
             .ToDictionary(entry => (TKey) entry.Key, entry => (TValue) entry.Value, comparer);
+
+    public static Array ToNonGenericArray<T>(this IEnumerable<T> source, Type elementType)
+    {
+        var sourceAsCollection = source as ICollection ?? source.ToArray();
+
+        var array = Array.CreateInstance(elementType, sourceAsCollection.Count);
+        sourceAsCollection.CopyTo(array, 0);
+
+        return array;
+    }
 }

CliFx/Utils/Extensions/PropertyExtensions.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Linq;
+using System.Reflection;
+
+namespace CliFx.Utils.Extensions;
+
+internal static class PropertyExtensions
+{
+    public static bool IsRequired(this PropertyInfo propertyInfo) =>
+        // Match attribute by name to avoid depending on .NET 7.0+ and to allow polyfilling
+        propertyInfo.GetCustomAttributes().Any(a =>
+            string.Equals(
+                a.GetType().FullName,
+                "System.Runtime.CompilerServices.RequiredMemberAttribute",
+                StringComparison.Ordinal
+            )
+        );
+}

CliFx/Utils/Extensions/TypeExtensions.cs

@@ -11,7 +11,8 @@ internal static class TypeExtensions
     public static bool Implements(this Type type, Type interfaceType) =>
         type.GetInterfaces().Contains(interfaceType);
 
-    public static Type? TryGetNullableUnderlyingType(this Type type) => Nullable.GetUnderlyingType(type);
+    public static Type? TryGetNullableUnderlyingType(this Type type) =>
+        Nullable.GetUnderlyingType(type);
 
     public static Type? TryGetEnumerableUnderlyingType(this Type type)
     {
@@ -44,16 +45,6 @@ internal static class TypeExtensions
         );
     }
 
-    public static Array ToNonGenericArray<T>(this IEnumerable<T> source, Type elementType)
-    {
-        var sourceAsCollection = source as ICollection ?? source.ToArray();
-
-        var array = Array.CreateInstance(elementType, sourceAsCollection.Count);
-        sourceAsCollection.CopyTo(array, 0);
-
-        return array;
-    }
-
     public static bool IsToStringOverriden(this Type type)
     {
         var toStringMethod = type.GetMethod(nameof(ToString), Type.EmptyTypes);

Readme.md

@@ -144,7 +144,7 @@ public class LogCommand : ICommand
 {
     // Order: 0
     [CommandParameter(0, Description = "Value whose logarithm is to be found.")]
-    public double Value { get; init; }
+    public required double Value { get; init; }
 
     // Name: --base
     // Short name: -b
@@ -382,7 +382,7 @@ If the user does not provide value for such option through command line argument
 [Command]
 public class AuthCommand : ICommand
 {
-    [CommandOption("token", IsRequired = true, EnvironmentVariable = "AUTH_TOKEN")]
+    [CommandOption("token", EnvironmentVariable = "AUTH_TOKEN")]
     public required string AuthToken { get; init; }
 
     public ValueTask ExecuteAsync(IConsole console)
@@ -499,10 +499,10 @@ This special exception can be used to print an error message to the console, ret
 [Command]
 public class DivideCommand : ICommand
 {
-    [CommandOption("dividend", IsRequired = true)]
+    [CommandOption("dividend")]
     public required double Dividend { get; init; }
 
-    [CommandOption("divisor", IsRequired = true)]
+    [CommandOption("divisor")]
     public required double Divisor { get; init; }
 
     public ValueTask ExecuteAsync(IConsole console)