Inspect sub-commands recursively when looking for long-short-options

Fixes #189

Author: TheConstructor

src/CommandLineUtils/Internal/CommandLineProcessor.cs

@@ -39,15 +39,20 @@ public CommandLineProcessor(CommandLineApplication command,
 
             // TODO in 3.0, remove this check, and make ClusterOptions true always
             // and make it an error to use short options with multiple characters
-            var allOptions = command.Commands.SelectMany(c => c.Options).Concat(command.GetOptions());
             if (!command.ClusterOptionsWasSetExplicitly)
             {
-                command.ClusterOptions = !allOptions.Any(o => o.ShortName != null && o.ShortName.Length > 1);
+                foreach (var option in AllOptions(command))
+                {
+                    if (option.ShortName != null && option.ShortName.Length != 1)
+                    {
+                        command.ClusterOptions = false;
+                        break;
+                    }
+                }
             }
-
-            if (command.ClusterOptions)
+            else if (command.ClusterOptions)
             {
-                foreach (var option in allOptions)
+                foreach (var option in AllOptions(command))
                 {
                     if (option.ShortName != null && option.ShortName.Length != 1)
                     {
@@ -58,6 +63,22 @@ public CommandLineProcessor(CommandLineApplication command,
             }
         }
 
+        static internal IEnumerable<CommandOption> AllOptions(CommandLineApplication command)
+        {
+            foreach (var option in command.Options)
+            {
+                yield return option;
+            }
+
+            foreach (var subCommand in command.Commands)
+            {
+                foreach (var option in AllOptions(subCommand))
+                {
+                    yield return option;
+                }
+            }
+        }
+
         public ParseResult Process()
         {
             _currentCommand = _initialCommand;

test/CommandLineUtils.Tests/CommandLineProcessorTests.cs

@@ -127,6 +127,20 @@ private class ShortNameType
             public string Auth { get; }
         }
 
+        [Command]
+        [Subcommand(typeof(ShortNameType))]
+        private class ParentCommand
+        {
+
+        }
+
+        [Command]
+        [Subcommand(typeof(ParentCommand))]
+        private class ParentParentCommand
+        {
+
+        }
+
         [Fact]
         public void ItInfersClusterOptionsCannotBeUsed()
         {
@@ -152,6 +166,22 @@ public void ItInfersClusterOptionsCannotBeUsed()
                 app.Parse();
                 Assert.False(app.ClusterOptions);
             }
+
+            {
+                var app = new CommandLineApplication<ParentCommand>();
+                app.Conventions.UseDefaultConventions();
+                Assert.False(app.ClusterOptionsWasSetExplicitly);
+                app.Parse();
+                Assert.False(app.ClusterOptions);
+            }
+
+            {
+                var app = new CommandLineApplication<ParentParentCommand>();
+                app.Conventions.UseDefaultConventions();
+                Assert.False(app.ClusterOptionsWasSetExplicitly);
+                app.Parse();
+                Assert.False(app.ClusterOptions);
+            }
         }
 
         [Fact]