refactor: enable nullable ref type checking (#425)

Directory.Build.props

@@ -32,7 +32,7 @@
  <WarningsNotAsErrors>$(WarningsNotAsErrors);1591</WarningsNotAsErrors>
  <LangVersion>9.0</LangVersion>
  <EnforceCodeStyleInBuild>true</EnforceCodeStyleInBuild>
- <Nullable>annotations</Nullable>
+ <Nullable>enable</Nullable>
  <AssemblyOriginatorKeyFile>$(MSBuildThisFileDirectory)src\StrongName.snk</AssemblyOriginatorKeyFile>
  <SignAssembly>true</SignAssembly>
 

src/CommandLineUtils/Attributes/AllowedValuesAttribute.cs

@@ -66,14 +66,14 @@ or StringComparison.InvariantCultureIgnoreCase
  }
 
  /// <inheritdoc />
- protected override ValidationResult IsValid(object value, ValidationContext validationContext)
+ protected override ValidationResult? IsValid(object? value, ValidationContext validationContext)
  {
  if (value is string str && _allowedValues.Any(t => str.Equals(t, Comparer)))
  {
  return ValidationResult.Success;
  }
 
- return new ValidationResult(FormatErrorMessage(value as string));
+ return new ValidationResult(FormatErrorMessage(value?.ToString() ?? string.Empty));
  }
  }
 }

src/CommandLineUtils/Attributes/FilePathExistsAttributeBase.cs

@@ -27,11 +27,11 @@ internal FilePathExistsAttributeBase(FilePathType filePathType)
  }
 
  /// <inheritdoc />
- protected override ValidationResult IsValid(object value, ValidationContext validationContext)
+ protected override ValidationResult? IsValid(object? value, ValidationContext validationContext)
  {
  if (value is not string path || path.Length == 0 || path.IndexOfAny(Path.GetInvalidPathChars()) >= 0)
  {
- return new ValidationResult(FormatErrorMessage(value as string));
+ return new ValidationResult(FormatErrorMessage(value?.ToString() ?? string.Empty));
  }
 
  if (!Path.IsPathRooted(path)
@@ -50,7 +50,7 @@ protected override ValidationResult IsValid(object value, ValidationContext vali
  return ValidationResult.Success;
  }
 
- return new ValidationResult(FormatErrorMessage(value as string));
+ return new ValidationResult(FormatErrorMessage(value?.ToString() ?? string.Empty));
  }
 
  private static string GetDefaultErrorMessage(FilePathType filePathType)

src/CommandLineUtils/Attributes/FilePathNotExistsAttributeBase.cs

@@ -27,11 +27,11 @@ internal FilePathNotExistsAttributeBase(FilePathType filePathType)
  }
 
  /// <inheritdoc />
- protected override ValidationResult IsValid(object value, ValidationContext validationContext)
+ protected override ValidationResult? IsValid(object? value, ValidationContext validationContext)
  {
  if (value is not string path || path.Length == 0 || path.IndexOfAny(Path.GetInvalidPathChars()) >= 0)
  {
- return new ValidationResult(FormatErrorMessage(value as string));
+ return new ValidationResult(FormatErrorMessage(value?.ToString() ?? string.Empty));
  }
 
  if (!Path.IsPathRooted(path)
@@ -55,7 +55,7 @@ protected override ValidationResult IsValid(object value, ValidationContext vali
  return ValidationResult.Success;
  }
 
- return new ValidationResult(FormatErrorMessage(value as string));
+ return new ValidationResult(FormatErrorMessage(value?.ToString() ?? string.Empty));
  }
 
  private static string GetDefaultErrorMessage(FilePathType filePathType)

src/CommandLineUtils/Attributes/LegalFilePathAttribute.cs

@@ -23,7 +23,7 @@ public LegalFilePathAttribute()
  }
 
  /// <inheritdoc />
- protected override ValidationResult IsValid(object value, ValidationContext validationContext)
+ protected override ValidationResult? IsValid(object? value, ValidationContext validationContext)
  {
  if (value is string path)
  {
@@ -37,7 +37,7 @@ protected override ValidationResult IsValid(object value, ValidationContext vali
  }
  }
 
- return new ValidationResult(FormatErrorMessage(value as string));
+ return new ValidationResult(FormatErrorMessage(value?.ToString() ?? string.Empty));
  }
  }
 }

src/CommandLineUtils/CommandArgument.cs

@@ -78,7 +78,7 @@ public IReadOnlyList<string?> Values
  /// <summary>
  /// Defines the underlying type of the argument for the help-text-generator
  /// </summary>
- internal Type UnderlyingType { get; set; }
+ internal Type? UnderlyingType { get; set; }
 
  /// <summary>
  /// Try to add a value to this argument.

src/CommandLineUtils/CommandArgument{T}.cs

@@ -52,9 +52,9 @@ public IReadOnlyList<T> ParsedValues
  ((IInternalCommandParamOfT)this).Parse(CultureInfo.CurrentCulture);
  }
 
- if (_parsedValues.Count == 0 && _hasDefaultValue)
+ if (_parsedValues.Count == 0 && _hasDefaultValue && DefaultValue != null)
  {
- return new[] { DefaultValue };
+ return new T[] { DefaultValue };
  }
 
  return _parsedValues;
@@ -85,7 +85,7 @@ void IInternalCommandParamOfT.Parse(CultureInfo culture)
  }
  }
 
- void SetBaseDefaultValue(T value)
+ void SetBaseDefaultValue(T? value)
  {
  if (!ReflectionHelper.IsSpecialValueTupleType(typeof(T), out _))
  {

src/CommandLineUtils/CommandLineApplication.Validation.cs

@@ -32,7 +32,7 @@ public Func<ValidationResult, int> ValidationErrorHandler
  /// Validates arguments and options.
  /// </summary>
  /// <returns>The first validation result that is not <see cref="ValidationResult.Success"/> if there is an error.</returns>
- public ValidationResult GetValidationResult()
+ public ValidationResult? GetValidationResult()
  {
  if (Parent != null)
  {

src/CommandLineUtils/CommandLineApplication.cs

@@ -863,7 +863,7 @@ public async Task<int> ExecuteAsync(string[] args, CancellationToken cancellatio
  }
 
  var validationResult = command.GetValidationResult();
- if (validationResult != ValidationResult.Success)
+ if (validationResult != null)
  {
  return command.ValidationErrorHandler(validationResult);
  }

src/CommandLineUtils/CommandLineApplication{T}.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 using McMaster.Extensions.CommandLineUtils.Abstractions;
 using McMaster.Extensions.CommandLineUtils.Conventions;
 using McMaster.Extensions.CommandLineUtils.HelpText;
@@ -15,6 +16,7 @@ namespace McMaster.Extensions.CommandLineUtils
  public class CommandLineApplication<TModel> : CommandLineApplication, IModelAccessor
  where TModel : class
  {
+ [AllowNull] // this is initialized in common method called in all constructors
  private Lazy<TModel> _lazy;
  private Func<TModel> _modelFactory = DefaultModelFactory;
 

src/CommandLineUtils/CommandOption.cs

@@ -137,7 +137,7 @@ public IReadOnlyList<string?> Values
  /// <summary>
  /// Defines the underlying type of the option for the help-text-generator
  /// </summary>
- internal Type UnderlyingType { get; set; }
+ internal Type? UnderlyingType { get; set; }
 
  /// <summary>
  /// A collection of validators that execute before invoking <see cref="CommandLineApplication.OnExecute(Func{int})"/>.

src/CommandLineUtils/CommandOption{T}.cs

@@ -53,7 +53,7 @@ public IReadOnlyList<T> ParsedValues
  ((IInternalCommandParamOfT)this).Parse(CultureInfo.CurrentCulture);
  }
 
- if (_parsedValues.Count == 0 && _hasDefaultValue)
+ if (_parsedValues.Count == 0 && _hasDefaultValue && DefaultValue != null)
  {
  return new[] { DefaultValue };
  }
@@ -86,7 +86,7 @@ void IInternalCommandParamOfT.Parse(CultureInfo culture)
  }
  }
 
- private void SetBaseDefaultValue(T value)
+ private void SetBaseDefaultValue(T? value)
  {
  if (!ReflectionHelper.IsSpecialValueTupleType(typeof(T), out _))
  {

src/CommandLineUtils/Conventions/ExecuteMethodConvention.cs

@@ -35,8 +35,8 @@ private async Task<int> OnExecute(ConventionContext context, CancellationToken c
  MethodInfo? asyncMethod;
  try
  {
- method = context.ModelType.GetMethod("OnExecute", binding);
- asyncMethod = context.ModelType.GetMethod("OnExecuteAsync", binding);
+ method = context.ModelType?.GetMethod("OnExecute", binding);
+ asyncMethod = context.ModelType?.GetMethod("OnExecuteAsync", binding);
  }
  catch (AmbiguousMatchException ex)
  {
@@ -75,7 +75,7 @@ private async Task<int> OnExecute(ConventionContext context, CancellationToken c
  throw new InvalidOperationException(Strings.InvalidOnExecuteReturnType(method.Name));
  }
 
- private async Task<int> InvokeAsync(MethodInfo method, object instance, object[] arguments)
+ private async Task<int> InvokeAsync(MethodInfo method, object instance, object?[] arguments)
  {
  try
  {
@@ -95,7 +95,7 @@ private async Task<int> InvokeAsync(MethodInfo method, object instance, object[]
  return 0;
  }
 
- private int Invoke(MethodInfo method, object instance, object[] arguments)
+ private int Invoke(MethodInfo method, object instance, object?[] arguments)
  {
  try
  {

src/CommandLineUtils/Conventions/SubcommandAttributeConvention.cs

@@ -67,7 +67,7 @@ private static readonly MethodInfo s_addSubcommandMethod
  private void AddSubcommandImpl<TSubCommand>(ConventionContext context)
  where TSubCommand : class
  {
- context.Application.Command<TSubCommand>(null, null);
+ context.Application.Command<TSubCommand>(null!, null!); // Hmm, should probably rethink this...
  }
  }
 }

src/CommandLineUtils/HelpText/DefaultHelpTextGenerator.cs

@@ -409,7 +409,7 @@ protected virtual string Format(CommandOption option)
  }
  }
 
- private string[] ExtractNamesFromEnum(Type type)
+ private string[] ExtractNamesFromEnum(Type? type)
  {
  if (type == null)
  {

src/CommandLineUtils/Internal/CommandLineProcessor.cs

@@ -335,7 +335,10 @@ private bool ProcessUnexpectedArg(string argTypeName, string? argValue = null)
 
  case UnrecognizedArgumentHandling.CollectAndContinue:
  var arg = _enumerator.Current;
- _currentCommand._remainingArguments.Add(arg.Raw);
+ if (arg != null)
+ {
+ _currentCommand._remainingArguments.Add(arg.Raw);
+ }
  return true;
 
  case UnrecognizedArgumentHandling.StopParsingAndCollect:

src/CommandLineUtils/Internal/ReflectionHelper.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Reflection;
 using System.Threading;
@@ -78,10 +79,10 @@ public static MemberInfo[] GetMembers(Type type)
  return GetAllMembers(type).ToArray();
  }
 
- public static object[] BindParameters(MethodInfo method, CommandLineApplication command, CancellationToken cancellationToken)
+ public static object?[] BindParameters(MethodInfo method, CommandLineApplication command, CancellationToken cancellationToken)
  {
  var methodParams = method.GetParameters();
- var arguments = new object[methodParams.Length];
+ var arguments = new object?[methodParams.Length];
 
  for (var i = 0; i < methodParams.Length; i++)
  {
@@ -117,15 +118,15 @@ public static object[] BindParameters(MethodInfo method, CommandLineApplication
  return arguments;
  }
 
- public static bool IsNullableType(Type type, out Type? wrappedType)
+ public static bool IsNullableType(Type type, [NotNullWhen(true)] out Type? wrappedType)
  {
  var result = type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Nullable<>);
  wrappedType = result ? type.GetGenericArguments().First() : null;
 
  return result;
  }
 
- public static bool IsSpecialValueTupleType(Type type, out Type? wrappedType)
+ public static bool IsSpecialValueTupleType(Type type, [NotNullWhen(true)] out Type? wrappedType)
  {
  var result = type.IsGenericType &&
  type.GetGenericTypeDefinition() == typeof(ValueTuple<,>) &&
@@ -135,7 +136,7 @@ public static bool IsSpecialValueTupleType(Type type, out Type? wrappedType)
  return result;
  }
 
- public static bool IsSpecialTupleType(Type type, out Type? wrappedType)
+ public static bool IsSpecialTupleType(Type type, [NotNullWhen(true)] out Type? wrappedType)
  {
  var result = type.IsGenericType &&
  type.GetGenericTypeDefinition() == typeof(Tuple<,>) &&

src/CommandLineUtils/Internal/ValueParsers/TypeDescriptorValueParserFactory.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.ComponentModel;
+using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 
 namespace McMaster.Extensions.CommandLineUtils.Abstractions
@@ -13,7 +14,7 @@ namespace McMaster.Extensions.CommandLineUtils.Abstractions
  /// </summary>
  internal class TypeDescriptorValueParserFactory
  {
- public bool TryGetParser<T>(out IValueParser parser)
+ public bool TryGetParser<T>([NotNullWhen(true)] out IValueParser? parser)
  {
  var targetType = typeof(T);
  var converter = TypeDescriptor.GetConverter(targetType);
@@ -39,7 +40,7 @@ public TypeConverterValueParser(Type targetType, TypeConverter typeConverter)
 
  private TypeConverter TypeConverter { get; }
 
- public T Parse(string argName, string value, CultureInfo culture)
+ public T Parse(string? argName, string? value, CultureInfo culture)
  {
  try
  {
@@ -52,7 +53,7 @@ public T Parse(string argName, string value, CultureInfo culture)
  }
  }
 
- object IValueParser.Parse(string argName, string value, CultureInfo culture)
+ object? IValueParser.Parse(string? argName, string? value, CultureInfo culture)
  => Parse(argName, value, culture);
  }
  }

src/CommandLineUtils/Properties/NullabilityHelpers.cs

@@ -0,0 +1,21 @@
+// Copyright (c) Nate McMaster.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+// Files here are for simplify annotations of nullable code and are not functional in .NET Standard 2.0
+#if NETSTANDARD2_0 || NET45
+namespace System.Diagnostics.CodeAnalysis
+{
+ // https://docs.microsoft.com/en-us/dotnet/api/system.diagnostics.codeanalysis.notnullwhenattribute?
+ [AttributeUsage(AttributeTargets.Parameter, Inherited = false)]
+ internal sealed class NotNullWhenAttribute : Attribute
+ {
+ public NotNullWhenAttribute(bool returnValue)
+ {
+ }
+ }
+
+ // https://docs.microsoft.com/en-us/dotnet/api/system.diagnostics.codeanalysis.allownullattribute
+ [System.AttributeUsage(System.AttributeTargets.Field | System.AttributeTargets.Parameter | System.AttributeTargets.Property, Inherited=false)]
+ internal sealed class AllowNullAttribute : Attribute { }
+}
+#endif