Alias for command branches (#411)

src/Spectre.Console.Cli/ConfiguratorExtensions.cs

@@ -181,7 +181,8 @@ public static class ConfiguratorExtensions
     /// <param name="configurator">The configurator.</param>
     /// <param name="name">The name of the command branch.</param>
     /// <param name="action">The command branch configuration.</param>
-    public static void AddBranch(
+    /// <returns>A branch configurator that can be used to configure the branch further.</returns>
+    public static IBranchConfigurator AddBranch(
         this IConfigurator configurator,
         string name,
         Action<IConfigurator<CommandSettings>> action)
@@ -191,7 +192,7 @@ public static class ConfiguratorExtensions
             throw new ArgumentNullException(nameof(configurator));
         }
 
-        configurator.AddBranch(name, action);
+        return configurator.AddBranch(name, action);
     }
 
     /// <summary>
@@ -201,7 +202,8 @@ public static class ConfiguratorExtensions
     /// <param name="configurator">The configurator.</param>
     /// <param name="name">The name of the command branch.</param>
     /// <param name="action">The command branch configuration.</param>
-    public static void AddBranch<TSettings>(
+    /// <returns>A branch configurator that can be used to configure the branch further.</returns>
+    public static IBranchConfigurator AddBranch<TSettings>(
         this IConfigurator<TSettings> configurator,
         string name,
         Action<IConfigurator<TSettings>> action)
@@ -212,7 +214,7 @@ public static class ConfiguratorExtensions
             throw new ArgumentNullException(nameof(configurator));
         }
 
-        configurator.AddBranch(name, action);
+        return configurator.AddBranch(name, action);
     }
 
     /// <summary>

src/Spectre.Console.Cli/IBranchConfigurator.cs

@@ -0,0 +1,14 @@
+namespace Spectre.Console.Cli;
+
+/// <summary>
+/// Represents a branch configurator.
+/// </summary>
+public interface IBranchConfigurator
+{
+    /// <summary>
+    /// Adds an alias (an alternative name) to the branch being configured.
+    /// </summary>
+    /// <param name="name">The alias to add to the branch being configured.</param>
+    /// <returns>The same <see cref="IBranchConfigurator"/> instance so that multiple calls can be chained.</returns>
+    IBranchConfigurator WithAlias(string name);
+}

src/Spectre.Console.Cli/IConfigurator.cs

@@ -41,6 +41,7 @@ public interface IConfigurator
     /// <typeparam name="TSettings">The command setting type.</typeparam>
     /// <param name="name">The name of the command branch.</param>
     /// <param name="action">The command branch configurator.</param>
-    void AddBranch<TSettings>(string name, Action<IConfigurator<TSettings>> action)
+    /// <returns>A branch configurator that can be used to configure the branch further.</returns>
+    IBranchConfigurator AddBranch<TSettings>(string name, Action<IConfigurator<TSettings>> action)
         where TSettings : CommandSettings;
 }

src/Spectre.Console.Cli/IConfiguratorOfT.cs

@@ -51,6 +51,7 @@ public interface IConfigurator<in TSettings>
     /// <typeparam name="TDerivedSettings">The derived command setting type.</typeparam>
     /// <param name="name">The name of the command branch.</param>
     /// <param name="action">The command branch configuration.</param>
-    void AddBranch<TDerivedSettings>(string name, Action<IConfigurator<TDerivedSettings>> action)
+    /// <returns>A branch configurator that can be used to configure the branch further.</returns>
+    IBranchConfigurator AddBranch<TDerivedSettings>(string name, Action<IConfigurator<TDerivedSettings>> action)
         where TDerivedSettings : TSettings;
 }

src/Spectre.Console.Cli/Internal/Configuration/BranchConfigurator.cs

@@ -0,0 +1,17 @@
+namespace Spectre.Console.Cli;
+
+internal sealed class BranchConfigurator : IBranchConfigurator
+{
+    public ConfiguredCommand Command { get; }
+
+    public BranchConfigurator(ConfiguredCommand command)
+    {
+        Command = command;
+    }
+
+    public IBranchConfigurator WithAlias(string alias)
+    {
+        Command.Aliases.Add(alias);
+        return this;
+    }
+}

src/Spectre.Console.Cli/Internal/Configuration/Configurator.cs

@@ -48,12 +48,13 @@ internal sealed class Configurator : IUnsafeConfigurator, IConfigurator, IConfig
         return new CommandConfigurator(command);
     }
 
-    public void AddBranch<TSettings>(string name, Action<IConfigurator<TSettings>> action)
+    public IBranchConfigurator AddBranch<TSettings>(string name, Action<IConfigurator<TSettings>> action)
         where TSettings : CommandSettings
     {
         var command = ConfiguredCommand.FromBranch<TSettings>(name);
         action(new Configurator<TSettings>(command, _registrar));
-        Commands.Add(command);
+        var added = Commands.AddAndReturn(command);
+        return new BranchConfigurator(added);
     }
 
     ICommandConfigurator IUnsafeConfigurator.AddCommand(string name, Type command)
@@ -74,7 +75,7 @@ internal sealed class Configurator : IUnsafeConfigurator, IConfigurator, IConfig
         return result;
     }
 
-    void IUnsafeConfigurator.AddBranch(string name, Type settings, Action<IUnsafeBranchConfigurator> action)
+    IBranchConfigurator IUnsafeConfigurator.AddBranch(string name, Type settings, Action<IUnsafeBranchConfigurator> action)
     {
         var command = ConfiguredCommand.FromBranch(settings, name);
 
@@ -86,6 +87,7 @@ internal sealed class Configurator : IUnsafeConfigurator, IConfigurator, IConfig
         }
 
         action(configurator);
-        Commands.Add(command);
+        var added = Commands.AddAndReturn(command);
+        return new BranchConfigurator(added);
     }
 }

src/Spectre.Console.Cli/Internal/Configuration/ConfiguratorOfT.cs

@@ -47,12 +47,13 @@ internal sealed class Configurator<TSettings> : IUnsafeBranchConfigurator, IConf
         return new CommandConfigurator(command);
     }
 
-    public void AddBranch<TDerivedSettings>(string name, Action<IConfigurator<TDerivedSettings>> action)
+    public IBranchConfigurator AddBranch<TDerivedSettings>(string name, Action<IConfigurator<TDerivedSettings>> action)
         where TDerivedSettings : TSettings
     {
         var command = ConfiguredCommand.FromBranch<TDerivedSettings>(name);
         action(new Configurator<TDerivedSettings>(command, _registrar));
-        _command.Children.Add(command);
+        var added = _command.Children.AddAndReturn(command);
+        return new BranchConfigurator(added);
     }
 
     ICommandConfigurator IUnsafeConfigurator.AddCommand(string name, Type command)
@@ -73,7 +74,7 @@ internal sealed class Configurator<TSettings> : IUnsafeBranchConfigurator, IConf
         return result;
     }
 
-    void IUnsafeConfigurator.AddBranch(string name, Type settings, Action<IUnsafeBranchConfigurator> action)
+    IBranchConfigurator IUnsafeConfigurator.AddBranch(string name, Type settings, Action<IUnsafeBranchConfigurator> action)
     {
         var command = ConfiguredCommand.FromBranch(settings, name);
 
@@ -85,6 +86,7 @@ internal sealed class Configurator<TSettings> : IUnsafeBranchConfigurator, IConf
         }
 
         action(configurator);
-        _command.Children.Add(command);
+        var added = _command.Children.AddAndReturn(command);
+        return new BranchConfigurator(added);
     }
 }

src/Spectre.Console.Cli/Unsafe/IUnsafeConfigurator.cs

@@ -19,5 +19,6 @@ public interface IUnsafeConfigurator
     /// <param name="name">The name of the command branch.</param>
     /// <param name="settings">The command setting type.</param>
     /// <param name="action">The command branch configurator.</param>
-    void AddBranch(string name, Type settings, Action<IUnsafeBranchConfigurator> action);
+    /// <returns>A branch configurator that can be used to configure the branch further.</returns>
+    IBranchConfigurator AddBranch(string name, Type settings, Action<IUnsafeBranchConfigurator> action);
 }

test/Spectre.Console.Cli.Tests/Unit/CommandAppTests.cs

@@ -280,6 +280,65 @@ public sealed partial class CommandAppTests
         });
     }
 
+    [Fact]
+    public void Should_Be_Able_To_Use_Branch_Alias()
+    {
+        // Given
+        var app = new CommandAppTester();
+        app.Configure(config =>
+        {
+            config.PropagateExceptions();
+            config.AddBranch<AnimalSettings>("animal", animal =>
+            {
+                animal.AddCommand<DogCommand>("dog");
+                animal.AddCommand<HorseCommand>("horse");
+            }).WithAlias("a");
+        });
+
+        // When
+        var result = app.Run(new[]
+        {
+            "a", "dog", "12", "--good-boy",
+            "--name", "Rufus",
+        });
+
+        // Then
+        result.ExitCode.ShouldBe(0);
+        result.Settings.ShouldBeOfType<DogSettings>().And(dog =>
+        {
+            dog.Age.ShouldBe(12);
+            dog.GoodBoy.ShouldBe(true);
+            dog.Name.ShouldBe("Rufus");
+            dog.IsAlive.ShouldBe(false);
+        });
+    }
+
+    [Fact]
+    public void Should_Throw_If_Branch_Alias_Conflicts_With_Another_Command()
+    {
+        // Given
+        var app = new CommandApp();
+        app.Configure(config =>
+        {
+            config.PropagateExceptions();
+            config.AddCommand<DogCommand>("a");
+            config.AddBranch<AnimalSettings>("animal", animal =>
+            {
+                animal.AddCommand<DogCommand>("dog");
+                animal.AddCommand<HorseCommand>("horse");
+            }).WithAlias("a");
+        });
+
+        // When
+        var result = Record.Exception(() => app.Run(new[] { "a", "0", "12" }));
+
+        // Then
+        result.ShouldBeOfType<CommandConfigurationException>().And(ex =>
+        {
+            ex.Message.ShouldBe("The alias 'a' for 'animal' conflicts with another command.");
+        });
+    }
+
     [Fact]
     public void Should_Assign_Default_Value_To_Optional_Argument()
     {