Remove dependencies (#2127)

* remove built-in parsers for IPAddress and IPEndPoint to reduce dependencies count and self-contained app size

* remove static cache of completion sources by source type to remove dependency to System.Collections.Concurrent

* remove dependency to System.Runtime.Serialization.Formatters.dll, use less reflection and drop non-generic collections support

* remove built-in parser for Uri (System.Private.Uri.dll)

* stop using Stack<T> because it's defined in System.Collections.dll

Author: adamsitnik

src/System.CommandLine.ApiCompatibility.Tests/ApiCompatibilityApprovalTests.System_CommandLine_api_is_not_changed.approved.txt

@@ -78,8 +78,6 @@ System.CommandLine
     public System.Void ThrowIfInvalid()
   public class CommandLineConfigurationException : System.Exception, System.Runtime.Serialization.ISerializable
     .ctor(System.String message)
-    .ctor()
-    .ctor(System.String message, System.Exception innerException)
   public static class CompletionSourceExtensions
     public static System.Void Add(this System.Collections.Generic.List<System.Func<System.CommandLine.Completions.CompletionContext,System.Collections.Generic.IEnumerable<System.CommandLine.Completions.CompletionItem>>> completionSources, System.Func<System.CommandLine.Completions.CompletionContext,System.Collections.Generic.IEnumerable<System.String>> completionsDelegate)
     public static System.Void Add(this System.Collections.Generic.List<System.Func<System.CommandLine.Completions.CompletionContext,System.Collections.Generic.IEnumerable<System.CommandLine.Completions.CompletionItem>>> completionSources, System.String[] completions)

src/System.CommandLine.NamingConventionBinder/ParameterDescriptor.cs

@@ -58,7 +58,7 @@ internal static bool CalculateAllowsNull(ParameterInfo parameterInfo)
     /// <inheritdoc />
     public object? GetDefaultValue() =>
         _parameterInfo.DefaultValue is DBNull
-            ? ArgumentConverter.GetDefaultValue(ValueType)
+            ? ValueType.GetDefaultValue()
             : _parameterInfo.DefaultValue;
 
     /// <inheritdoc />

src/System.CommandLine.NamingConventionBinder/PropertyDescriptor.cs

@@ -36,7 +36,7 @@ internal PropertyDescriptor(
     public bool HasDefaultValue => false;
 
     /// <inheritdoc />
-    public object? GetDefaultValue() => ArgumentConverter.GetDefaultValue(ValueType);
+    public object? GetDefaultValue() => ValueType.GetDefaultValue();
 
     /// <summary>
     /// Sets a value on the target property.

src/System.CommandLine.NamingConventionBinder/TypeExtensions.cs

@@ -1,7 +1,10 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
+using System.Collections;
+using System.CommandLine.Binding;
 using System.Runtime.CompilerServices;
+using System.Runtime.Serialization;
 
 namespace System.CommandLine.NamingConventionBinder;
 
@@ -28,4 +31,28 @@ public static bool IsConstructedGenericTypeOf(this Type type, Type genericTypeDe
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static bool IsNullableValueType(this Type type)
         => type.IsValueType && type.IsConstructedGenericTypeOf(typeof(Nullable<>));
+
+    internal static object? GetDefaultValue(this Type type)
+    {
+        if (type.IsNullable())
+        {
+            return null;
+        }
+
+        if (type.GetElementTypeIfEnumerable() is { } itemType)
+        {
+            return ArgumentConverter.CreateEnumerable(type, itemType);
+        }
+
+        return type switch
+        {
+            { } nonGeneric
+                when nonGeneric == typeof(IList) ||
+                     nonGeneric == typeof(ICollection) ||
+                     nonGeneric == typeof(IEnumerable)
+                => Array.Empty<object>(),
+            _ when type.IsValueType => FormatterServices.GetUninitializedObject(type),
+            _ => null
+        };
+    }
 }

src/System.CommandLine.Tests/Binding/TypeConversionTests.cs

@@ -531,8 +531,15 @@ public void Values_can_be_correctly_converted_to_nullable_TimeSpan_without_the_p
         }
 
         [Fact]
-        public void Values_can_be_correctly_converted_to_Uri_without_the_parser_specifying_a_custom_converter()
-            => GetValue(new Option<Uri>("-x"), "-x http://example.com").Should().BeEquivalentTo(new Uri("http://example.com"));
+        public void Values_can_be_correctly_converted_to_Uri_when_custom_parser_is_provided()
+        {
+            Option<Uri> option = new ("-x")
+            {
+                CustomParser = (argumentResult) => Uri.TryCreate(argumentResult.Tokens.Last().Value, UriKind.RelativeOrAbsolute, out var uri) ? uri : null
+            };
+
+            GetValue(option, "-x http://example.com").Should().BeEquivalentTo(new Uri("http://example.com"));
+        }
 
         [Fact]
         public void Options_with_arguments_specified_can_be_correctly_converted_to_bool_without_the_parser_specifying_a_custom_converter()
@@ -582,13 +589,27 @@ public void Values_can_be_correctly_converted_to_nullable_sbyte_without_the_pars
             => GetValue(new Option<sbyte?>("-us"), "-us 123").Should().Be(123);
 
         [Fact]
-        public void Values_can_be_correctly_converted_to_ipaddress_without_the_parser_specifying_a_custom_converter()
-            => GetValue(new Option<IPAddress>("-us"), "-us 1.2.3.4").Should().Be(IPAddress.Parse("1.2.3.4"));
+        public void Values_can_be_correctly_converted_to_ipaddress_when_custom_parser_is_provided()
+        {
+            Option<IPAddress> option = new ("-us")
+            { 
+                CustomParser = (argumentResult) => IPAddress.Parse(argumentResult.Tokens.Last().Value)
+            };
+
+            GetValue(option, "-us 1.2.3.4").Should().Be(IPAddress.Parse("1.2.3.4"));
+        }
 
 #if NETCOREAPP3_0_OR_GREATER
         [Fact]
-        public void Values_can_be_correctly_converted_to_ipendpoint_without_the_parser_specifying_a_custom_converter()
-            => GetValue(new Option<IPEndPoint>("-us"), "-us 1.2.3.4:56").Should().Be(IPEndPoint.Parse("1.2.3.4:56"));
+        public void Values_can_be_correctly_converted_to_ipendpoint_when_custom_parser_is_provided()
+        {
+            Option<IPEndPoint> option = new("-us")
+            {
+                CustomParser = (argumentResult) => IPEndPoint.Parse(argumentResult.Tokens.Last().Value)
+            };
+
+            GetValue(option, "-us 1.2.3.4:56").Should().Be(IPEndPoint.Parse("1.2.3.4:56"));
+        }
 #endif
 
 #if NET6_0_OR_GREATER
@@ -756,9 +777,6 @@ public void String_defaults_to_null_when_not_specified_only_for_not_required_arg
         [InlineData(typeof(string[]))]
         [InlineData(typeof(int[]))]
         [InlineData(typeof(FileAccess[]))]
-        [InlineData(typeof(IEnumerable))]
-        [InlineData(typeof(ICollection))]
-        [InlineData(typeof(IList))]
         public void Sequence_type_defaults_to_empty_when_not_specified(Type sequenceType)
         {
             var argument = Activator.CreateInstance(typeof(Argument<>).MakeGenericType(sequenceType), new object[] { "argName" });

src/System.CommandLine/Argument.cs

@@ -54,11 +54,40 @@ internal TryConvertArgument? ConvertArguments
         /// <summary>
         /// Gets the list of completion sources for the argument.
         /// </summary>
-        public List<Func<CompletionContext, IEnumerable<CompletionItem>>> CompletionSources =>
-            _completionSources ??= new ()
+        public List<Func<CompletionContext, IEnumerable<CompletionItem>>> CompletionSources
+        {
+            get
             {
-                CompletionSource.ForType(ValueType)
-            };
+                if (_completionSources is null)
+                {
+                    Type? valueType = ValueType;
+                    if (valueType == typeof(bool) || valueType == typeof(bool?))
+                    {
+                        _completionSources = new ()
+                        {
+                            static _ => new CompletionItem[]
+                            {
+                                new(bool.TrueString),
+                                new(bool.FalseString)
+                            }
+                        };
+                    }
+                    else if (!valueType.IsPrimitive && (valueType.IsEnum || (valueType.TryGetNullableType(out valueType) && valueType.IsEnum)))
+                    {
+                        _completionSources = new()
+                        {
+                            _ => Enum.GetNames(valueType).Select(n => new CompletionItem(n))
+                        };
+                    }
+                    else
+                    {
+                        _completionSources = new();
+                    }
+                }
+
+                return _completionSources;
+            }
+        }
 
         /// <summary>
         /// Gets or sets the <see cref="Type" /> that the argument token(s) will be converted to.

src/System.CommandLine/Argument{T}.cs

@@ -1,7 +1,9 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
+using System.Collections.Generic;
 using System.CommandLine.Parsing;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 
 namespace System.CommandLine
@@ -160,5 +162,36 @@ public void AcceptLegalFileNamesOnly()
                 }
             });
         }
+
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL3050", Justification = "https://github.com/dotnet/command-line-api/issues/1638")]
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2091", Justification = "https://github.com/dotnet/command-line-api/issues/1638")]
+        internal static T? CreateDefaultValue()
+        {
+            if (default(T) is null && typeof(T) != typeof(string))
+            {
+                if (typeof(T).IsArray)
+                {
+                    return (T?)(object)Array.CreateInstance(typeof(T).GetElementType()!, 0);
+                }
+                else if (typeof(T).IsGenericType)
+                {
+                    var genericTypeDefinition = typeof(T).GetGenericTypeDefinition();
+
+                    if (genericTypeDefinition == typeof(IEnumerable<>) ||
+                        genericTypeDefinition == typeof(IList<>) ||
+                        genericTypeDefinition == typeof(ICollection<>))
+                    {
+                        return (T?)(object)Array.CreateInstance(typeof(T).GenericTypeArguments[0], 0);
+                    }
+
+                    if (genericTypeDefinition == typeof(List<>))
+                    {
+                        return Activator.CreateInstance<T>();
+                    }
+                }
+            }
+
+            return default;
+        }
     }
 }

src/System.CommandLine/Binding/ArgumentConverter.DefaultValues.cs

@@ -5,7 +5,6 @@
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
-using System.Runtime.Serialization;
 
 namespace System.CommandLine.Binding;
 
@@ -37,7 +36,7 @@ private static IList CreateEmptyList(Type listType)
         return (IList)ctor.Invoke(null);
     }
 
-    private static IList CreateEnumerable(Type type, Type itemType, int capacity = 0)
+    internal static IList CreateEnumerable(Type type, Type itemType, int capacity = 0)
     {
         if (type.IsArray)
         {
@@ -63,9 +62,4 @@ private static IList CreateEnumerable(Type type, Type itemType, int capacity = 0
 
         throw new ArgumentException($"Type {type} cannot be created without a custom binder.");
     }
-
-    [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2067:UnrecognizedReflectionPattern",
-                                  Justification = $"{nameof(CreateDefaultValueType)} is only called on a ValueType. You can always create an instance of a ValueType.")]
-    private static object CreateDefaultValueType(Type type) =>
-        FormatterServices.GetUninitializedObject(type);
 }

src/System.CommandLine/Binding/ArgumentConverter.StringConverters.cs

@@ -3,15 +3,17 @@
 
 using System.Collections.Generic;
 using System.IO;
-using System.Net;
 
 namespace System.CommandLine.Binding;
 
 internal static partial class ArgumentConverter
 {
     private delegate bool TryConvertString(string token, out object? value);
 
-    private static readonly Dictionary<Type, TryConvertString> _stringConverters = new()
+    private static Dictionary<Type, TryConvertString>? _stringConverters;
+
+    private static Dictionary<Type, TryConvertString> StringConverters
+        => _stringConverters ??= new()
     {
         [typeof(bool)] = (string token, out object? value) =>
         {
@@ -169,32 +171,6 @@ internal static partial class ArgumentConverter
             return false;
         },
 
-        [typeof(IPAddress)] = (string token, out object? value) =>
-        {
-            if (IPAddress.TryParse(token, out var ip))
-            {
-                value = ip;
-                return true;
-            }
-
-            value = default;
-            return false;
-        },
-
-#if NETCOREAPP3_0_OR_GREATER
-        [typeof(IPEndPoint)] = (string token, out object? value) =>
-        {
-            if (IPEndPoint.TryParse(token, out var ipendpoint))
-            {
-                value = ipendpoint;
-                return true;
-            }
-
-            value = default;
-            return false;
-        },
-#endif
-
         [typeof(long)] = (string token, out object? value) =>
         {
             if (long.TryParse(token, out var longValue))
@@ -299,18 +275,6 @@ internal static partial class ArgumentConverter
             return false;
         },
 
-        [typeof(Uri)] = (string input, out object? value) =>
-        {
-            if (Uri.TryCreate(input, UriKind.RelativeOrAbsolute, out var uri))
-            {
-                value = uri;
-                return true;
-            }
-
-            value = default;
-            return false;
-        },
-
         [typeof(TimeSpan)] = (string input, out object? value) =>
         {
             if (TimeSpan.TryParse(input, out var timeSpan))

src/System.CommandLine/Binding/ArgumentConverter.cs

@@ -1,7 +1,6 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-using System.Collections;
 using System.Collections.Generic;
 using System.CommandLine.Parsing;
 using static System.CommandLine.Binding.ArgumentConversionResult;
@@ -40,7 +39,7 @@ private static ArgumentConversionResult ConvertToken(
                 return ConvertToken(argumentResult, nullableType, token);
             }
 
-            if (_stringConverters.TryGetValue(type, out var tryConvert))
+            if (StringConverters.TryGetValue(type, out var tryConvert))
             {
                 if (tryConvert(value, out var converted))
                 {
@@ -123,12 +122,12 @@ private static ArgumentConversionResult ConvertTokens(
             if (argument.Arity is { MaximumNumberOfValues: 1, MinimumNumberOfValues: 1 })
             {
                 if (argument.ValueType.TryGetNullableType(out var nullableType) &&
-                    _stringConverters.TryGetValue(nullableType, out var convertNullable))
+                    StringConverters.TryGetValue(nullableType, out var convertNullable))
                 {
                     return (ArgumentResult result, out object? value) => ConvertSingleString(result, convertNullable, out value);
                 }
 
-                if (_stringConverters.TryGetValue(argument.ValueType, out var convert1))
+                if (StringConverters.TryGetValue(argument.ValueType, out var convert1))
                 {
                     return (ArgumentResult result, out object? value) => ConvertSingleString(result, convert1, out value);
                 }
@@ -224,29 +223,5 @@ public static bool TryConvertArgument(ArgumentResult argumentResult, out object?
             value = result;
             return result.Result == ArgumentConversionResultType.Successful;
         }
-
-        internal static object? GetDefaultValue(Type type)
-        {
-            if (type.IsNullable())
-            {
-                return null;
-            }
-
-            if (type.GetElementTypeIfEnumerable() is { } itemType)
-            {
-                return CreateEnumerable(type, itemType);
-            }
-
-            return type switch
-            {
-                { } nonGeneric
-                    when nonGeneric == typeof(IList) ||
-                         nonGeneric == typeof(ICollection) ||
-                         nonGeneric == typeof(IEnumerable)
-                    => Array.Empty<object>(),
-                _ when type.IsValueType => CreateDefaultValueType(type),
-                _ => null
-            };
-        }
     }
 }