dotnet · adamsitnik · Dec 14, 2022 · Dec 12, 2022 · Dec 12, 2022 · Dec 12, 2022
diff --git a/...ty.Tests/ApiCompatibilityApprovalTests.System_CommandLine_api_is_not_changed.approved.txt b/...ty.Tests/ApiCompatibilityApprovalTests.System_CommandLine_api_is_not_changed.approved.txt
@@ -148,7 +148,6 @@ System.CommandLine
   public interface IConsole : System.CommandLine.IO.IStandardError, System.CommandLine.IO.IStandardIn, System.CommandLine.IO.IStandardOut
   public abstract class IdentifierSymbol : Symbol
     public System.Collections.Generic.IReadOnlyCollection<System.String> Aliases { get; }
-    public System.String Name { get; set; }
     public System.Void AddAlias(System.String alias)
     public System.Boolean HasAlias(System.String alias)
   public class LocalizationResources
@@ -196,7 +195,6 @@ System.CommandLine
     public System.Boolean IsRequired { get; set; }
     public System.Type ValueType { get; }
     public System.Collections.Generic.IEnumerable<System.CommandLine.Completions.CompletionItem> GetCompletions(System.CommandLine.Completions.CompletionContext context)
-    public System.Boolean HasAliasIgnoringPrefix(System.String alias)
     public ParseResult Parse(System.String commandLine)
     public ParseResult Parse(System.String[] args)
   public class Option<T> : Option, IValueDescriptor<T>, System.CommandLine.Binding.IValueDescriptor

diff --git a/src/System.CommandLine.DragonFruit/CommandLine.cs b/src/System.CommandLine.DragonFruit/CommandLine.cs
@@ -197,7 +197,7 @@ public static CommandLineBuilder ConfigureHelpFromXmlComments(
                     {
                         var kebabCasedParameterName = parameterDescription.Key.ToKebabCase();
 
-                        var option = builder.Command.Options.FirstOrDefault(o => o.HasAliasIgnoringPrefix(kebabCasedParameterName));
+                        var option = builder.Command.Options.FirstOrDefault(o => HasAliasIgnoringPrefix(o, kebabCasedParameterName));
 
                         if (option != null)
                         {
@@ -300,5 +300,39 @@ private static string GetDefaultXmlDocsFileLocation(Assembly assembly)
 
             return string.Empty;
         }
+
+        /// <summary>
+        /// Indicates whether a given alias exists on the option, regardless of its prefix.
+        /// </summary>
+        /// <param name="alias">The alias, which can include a prefix.</param>
+        /// <returns><see langword="true"/> if the alias exists; otherwise, <see langword="false"/>.</returns>
+        private static bool HasAliasIgnoringPrefix(Option option, string alias)
+        {
+            ReadOnlySpan<char> rawAlias = alias.AsSpan(GetPrefixLength(alias));
+
+            foreach (string existingAlias in option.Aliases)
+            {
+                if (MemoryExtensions.Equals(existingAlias.AsSpan(GetPrefixLength(existingAlias)), rawAlias, StringComparison.CurrentCulture))
+                {
+                    return true;
+                }
+            }
+
+            return false;
+
+            static int GetPrefixLength(string alias)
+            {
+                if (alias[0] == '-')
+                {
+                    return alias.Length > 1 && alias[1] == '-' ? 2 : 1;
+                }
+                else if (alias[0] == '/')
+                {
+                    return 1;
+                }
+
+                return 0;
+            }
+        }
     }
 }
diff --git a/src/System.CommandLine.Tests/OptionTests.cs b/src/System.CommandLine.Tests/OptionTests.cs
@@ -64,7 +64,6 @@ public void A_prefixed_alias_can_be_added_to_an_option()
 
             option.AddAlias("-a");
 
-            option.HasAliasIgnoringPrefix("a").Should().BeTrue();
             option.HasAlias("-a").Should().BeTrue();
         }
 
@@ -84,14 +83,6 @@ public void HasAlias_accepts_prefixed_short_value()
             option.HasAlias("-o").Should().BeTrue();
         }
 
-        [Fact]
-        public void HasAliasIgnorePrefix_accepts_unprefixed_short_value()
-        {
-            var option = new Option<string>(new[] { "-o", "--option" });
-
-            option.HasAliasIgnoringPrefix("o").Should().BeTrue();
-        }
-
         [Fact]
         public void HasAlias_accepts_prefixed_long_value()
         {
@@ -100,14 +91,6 @@ public void HasAlias_accepts_prefixed_long_value()
             option.HasAlias("--option").Should().BeTrue();
         }
 
-        [Fact]
-        public void HasAliasIgnorePrefix_accepts_unprefixed_long_value()
-        {
-            var option = new Option<string>(new[] { "-o", "--option" });
-
-            option.HasAliasIgnoringPrefix("option").Should().BeTrue();
-        }
-
         [Fact]
         public void It_is_not_necessary_to_specify_a_prefix_when_adding_an_option()
         {

diff --git a/src/System.CommandLine/Binding/ArgumentConversionResult.cs b/src/System.CommandLine/Binding/ArgumentConversionResult.cs
@@ -56,7 +56,7 @@ private static string FormatErrorMessage(
             if (argument.FirstParent?.Symbol is IdentifierSymbol identifierSymbol &&
                 argument.FirstParent.Next is null)
             {
-                var alias = identifierSymbol.Aliases.First();
+                var alias = identifierSymbol.GetLongestAlias(removePrefix: false);
 
                 switch (identifierSymbol)
                 {

diff --git a/src/System.CommandLine/IdentifierSymbol.cs b/src/System.CommandLine/IdentifierSymbol.cs
@@ -2,6 +2,7 @@
 // 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;
 
 namespace System.CommandLine
@@ -11,8 +12,7 @@ namespace System.CommandLine
     /// </summary>
     public abstract class IdentifierSymbol : Symbol
     {
-        private protected readonly HashSet<string> _aliases = new(StringComparer.Ordinal);
-        private string? _specifiedName;
+        private readonly HashSet<string> _aliases = new(StringComparer.Ordinal);
 
         /// <summary>
         /// Initializes a new instance of the <see cref="IdentifierSymbol"/> class.
@@ -30,7 +30,7 @@ protected IdentifierSymbol(string? description = null)
         /// <param name="description">The description of the symbol, which is displayed in command line help.</param>
         protected IdentifierSymbol(string name, string? description = null) 
         {
-            Name = name;
+            Name = name ?? throw new ArgumentNullException(nameof(name));
             Description = description;
         }
 
@@ -42,19 +42,18 @@ protected IdentifierSymbol(string name, string? description = null)
         /// <inheritdoc/>
         public override string Name
         {
-            get => _specifiedName ??= DefaultName;
             set
             {
-                if (_specifiedName is null || !string.Equals(_specifiedName, value, StringComparison.Ordinal))
+                if (_name is null || !string.Equals(_name, value, StringComparison.Ordinal))
                 {
                     AddAlias(value);
 
-                    if (_specifiedName is { })
+                    if (_name != null)
                     {
-                        RemoveAlias(_specifiedName);
+                        RemoveAlias(_name);
                     }
 
-                    _specifiedName = value;
+                    _name = value;
                 }
             }
         }
@@ -82,6 +81,19 @@ public void AddAlias(string alias)
         /// <returns><see langword="true" /> if the alias has already been defined; otherwise <see langword="false" />.</returns>
         public bool HasAlias(string alias) => _aliases.Contains(alias);
 
+        internal string GetLongestAlias(bool removePrefix)
+        {
+            string max = "";
+            foreach (string alias in _aliases)
+            {
+                if (alias.Length > max.Length)
+                {
+                    max = alias;
+                }
+            }
+            return removePrefix ? max.RemovePrefix() : max;
+        }
+
         [DebuggerStepThrough]
         private void ThrowIfAliasIsInvalid(string alias)
         {

diff --git a/src/System.CommandLine/LocalizationResources.cs b/src/System.CommandLine/LocalizationResources.cs
@@ -102,7 +102,7 @@ public virtual string RequiredCommandWasNotProvided() =>
         ///   Interpolates values into a localized string similar to Option '{0}' is required.
         /// </summary>
         public virtual string RequiredOptionWasNotProvided(Option option) =>
-            GetResourceString(Properties.Resources.RequiredOptionWasNotProvided, option.Aliases.OrderByDescending(x => x.Length).First());
+            GetResourceString(Properties.Resources.RequiredOptionWasNotProvided, option.GetLongestAlias(removePrefix: false));
 
         /// <summary>
         ///   Interpolates values into a localized string similar to Argument &apos;{0}&apos; not recognized. Must be one of:{1}.

diff --git a/src/System.CommandLine/Option.cs b/src/System.CommandLine/Option.cs
@@ -15,7 +15,6 @@ namespace System.CommandLine
     /// <seealso cref="IdentifierSymbol" />
     public abstract class Option : IdentifierSymbol, IValueDescriptor
     {
-        private string? _name;
         private List<Action<OptionResult>>? _validators;
 
         private protected Option(string name, string? description) : base(description)
@@ -25,8 +24,6 @@ private protected Option(string name, string? description) : base(description)
                 throw new ArgumentNullException(nameof(name));
             }
 
-            _name = name.RemovePrefix();
-
             AddAlias(name);
         }
 
@@ -82,45 +79,10 @@ public ArgumentArity Arity
 
         internal bool DisallowBinding { get; init; }
 
-        /// <inheritdoc />
-        public override string Name
-        {
-            set
-            {
-                if (!HasAlias(value))
-                {
-                    _name = null;
-                    RemoveAlias(DefaultName);
-                }
-
-                base.Name = value;
-            }
-        }
-
         internal List<Action<OptionResult>> Validators => _validators ??= new();
 
         internal bool HasValidators => _validators is not null && _validators.Count > 0;
 
-        /// <summary>
-        /// Indicates whether a given alias exists on the option, regardless of its prefix.
-        /// </summary>
-        /// <param name="alias">The alias, which can include a prefix.</param>
-        /// <returns><see langword="true"/> if the alias exists; otherwise, <see langword="false"/>.</returns>
-        public bool HasAliasIgnoringPrefix(string alias)
-        {
-            ReadOnlySpan<char> rawAlias = alias.AsSpan(alias.GetPrefixLength());
-
-            foreach (string existingAlias in _aliases)
-            {
-                if (MemoryExtensions.Equals(existingAlias.AsSpan(existingAlias.GetPrefixLength()), rawAlias, StringComparison.CurrentCulture))
-                {
-                    return true;
-                }
-            }
-
-            return false;
-        }
-
         /// <summary>
         /// Gets a value that indicates whether multiple argument tokens are allowed for each option identifier token.
         /// </summary>
@@ -137,7 +99,7 @@ public bool HasAliasIgnoringPrefix(string alias)
         public bool AllowMultipleArgumentsPerToken { get; set; }
 
         internal virtual bool IsGreedy
-            => Argument is not null && Argument.Arity.MinimumNumberOfValues > 0 && Argument.ValueType != typeof(bool);
+            => Argument.Arity.MinimumNumberOfValues > 0 && Argument.ValueType != typeof(bool);
 
         /// <summary>
         /// Indicates whether the option is required when its parent command is invoked.
@@ -156,20 +118,7 @@ internal virtual bool IsGreedy
 
         object? IValueDescriptor.GetDefaultValue() => Argument.GetDefaultValue();
 
-        private protected override string DefaultName => _name ??= GetLongestAlias();
-
-        private string GetLongestAlias()
-        {
-            string max = "";
-            foreach (string alias in _aliases)
-            {
-                if (alias.Length > max.Length)
-                {
-                    max = alias;
-                }
-            }
-            return max.RemovePrefix();
-        }
+        private protected override string DefaultName => GetLongestAlias(true);
 
         /// <inheritdoc />
         public override IEnumerable<CompletionItem> GetCompletions(CompletionContext context)

diff --git a/src/System.CommandLine/Parsing/StringExtensions.cs b/src/System.CommandLine/Parsing/StringExtensions.cs
@@ -32,7 +32,7 @@ internal static string RemovePrefix(this string alias)
                        : alias;
         }
 
-        internal static int GetPrefixLength(this string alias)
+        private static int GetPrefixLength(this string alias)
         {
             if (alias[0] == '-')
             {

diff --git a/src/System.CommandLine/Parsing/SymbolResultExtensions.cs b/src/System.CommandLine/Parsing/SymbolResultExtensions.cs
@@ -2,7 +2,6 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System.Collections.Generic;
-using System.Linq;
 
 namespace System.CommandLine.Parsing
 {
@@ -31,11 +30,7 @@ internal static Token Token(this SymbolResult symbolResult)
 
             Token CreateImplicitToken(Option option)
             {
-                var optionName = option.Name;
-
-                var defaultAlias = option.Aliases.First(alias => alias.RemovePrefix() == optionName);
-
-                return new Token(defaultAlias, TokenType.Option, option, Parsing.Token.ImplicitPosition);
+                return new Token(option.GetLongestAlias(removePrefix: false), TokenType.Option, option, Parsing.Token.ImplicitPosition);
             }
         }
     }

diff --git a/src/System.CommandLine/Symbol.cs b/src/System.CommandLine/Symbol.cs
@@ -11,7 +11,7 @@ namespace System.CommandLine
     /// </summary>
     public abstract class Symbol
     {
-        private string? _name;
+        private protected string? _name;
         private ParentNode? _firstParent;
 
         private protected Symbol()