Fix issues for HelpText.AutoBuild configuration (issues #224 , # 259)

src/CommandLine/ErrorExtensions.cs

@@ -23,5 +23,6 @@ public static IEnumerable<Error> OnlyMeaningfulOnes(this IEnumerable<Error> erro
                 .Where(e => !(e.Tag == ErrorType.UnknownOptionError
                     && ((UnknownOptionError)e).Token.EqualsOrdinalIgnoreCase("help")));
         }
+
     }
 }

src/CommandLine/HelpTextExtensions.cs

@@ -0,0 +1,45 @@
+// Copyright 2005-2015 Giacomo Stelluti Scala & Contributors. All rights reserved. See License.md in the project root for license information.
+using System;
+using System.IO;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace CommandLine
+{
+    public static class HelpTextExtensions
+    {
+        /// <summary>
+        ///  return true when errors contain HelpXXXError
+        /// </summary>
+        public static bool IsHelp(this IEnumerable<Error> errs)
+        {
+            if (errs.Any(x => x.Tag == ErrorType.HelpRequestedError ||
+                            x.Tag == ErrorType.HelpVerbRequestedError))
+                return true;
+            //when  AutoHelp=false in parser, help is disabled  and Parser raise UnknownOptionError
+            return errs.Any(x => (x is UnknownOptionError ee ? ee.Token : "") == "help");
+        }
+
+        /// <summary>
+        ///  return true when errors contain VersionXXXError
+        /// </summary>
+        public static bool IsVersion(this IEnumerable<Error> errs)
+        {
+            if (errs.Any(x => x.Tag == ErrorType.VersionRequestedError))
+                return true;
+            //when  AutoVersion=false in parser, Version is disabled  and Parser raise UnknownOptionError
+            return errs.Any(x => (x is UnknownOptionError ee ? ee.Token : "") == "version");
+        }
+		 /// <summary>
+        ///  redirect errs to Console.Error, and to Console.Out for help/version error
+        /// </summary>
+		 public static TextWriter Output(this IEnumerable<Error> errs)
+        {
+           if (errs.IsHelp() || errs.IsVersion())
+			   return Console.Out;
+		   return Console.Error;
+        }
+    }
+}
+
+

src/CommandLine/Text/HelpText.cs

@@ -269,11 +269,11 @@ public static HelpText AutoBuild<T>(
 
             var errors = Enumerable.Empty<Error>();
 
+
             if (onError != null && parserResult.Tag == ParserResultType.NotParsed)
             {
                 errors = ((NotParsed<T>)parserResult).Errors;
-
-                if (errors.OnlyMeaningfulOnes().Any())
+                if (errors.IsHelp() || errors.OnlyMeaningfulOnes().Any())
                     auto = onError(auto);
             }
 

tests/CommandLine.Tests/Unit/Text/HelpTextAutoBuildFix.cs

@@ -0,0 +1,93 @@
+using System;
+using System.Linq;
+using CommandLine.Tests.Fakes;
+using CommandLine.Text;
+using FluentAssertions;
+using Xunit;
+
+namespace CommandLine.Tests.Unit.Text
+{
+    public class HelpTextAutoBuildFix
+    {
+
+        [Fact]
+        public void HelpText_wit_AdditionalNewLineAfterOption_true_should_have_newline()
+        {
+            // Fixture setup
+            // Exercize system 
+            var sut = new HelpText { AdditionalNewLineAfterOption = true }
+                .AddOptions(new NotParsed<Simple_Options>(TypeInfo.Create(typeof(Simple_Options)),
+                    Enumerable.Empty<Error>()));
+
+            // Verify outcome
+
+            var lines = sut.ToString().ToLines();
+
+            lines[2].Should().BeEquivalentTo("  stringvalue        Define a string value here.");
+            lines[3].Should().BeEquivalentTo(String.Empty);
+            lines[4].Should().BeEquivalentTo("  s, shortandlong    Example with both short and long name.");
+            lines[5].Should().BeEquivalentTo(String.Empty);
+            lines[7].Should().BeEquivalentTo(String.Empty);
+            lines[9].Should().BeEquivalentTo(String.Empty);
+            lines[11].Should().BeEquivalentTo(String.Empty);
+            lines[13].Should().BeEquivalentTo(String.Empty);
+            lines[14].Should().BeEquivalentTo("  value pos. 0       Define a long value here.");
+            // Teardown
+        }
+
+        [Fact]
+        public void HelpText_wit_AdditionalNewLineAfterOption_false_should_not_have_newline()
+        {
+            // Fixture setup
+            // Exercize system 
+            var sut = new HelpText { AdditionalNewLineAfterOption = false }
+                .AddOptions(new NotParsed<Simple_Options>(TypeInfo.Create(typeof(Simple_Options)),
+                    Enumerable.Empty<Error>()));
+
+            // Verify outcome
+
+            var lines = sut.ToString().ToLines();
+
+            lines[2].Should().BeEquivalentTo("  stringvalue        Define a string value here.");
+
+            lines[3].Should().BeEquivalentTo("  s, shortandlong    Example with both short and long name.");
+            lines[8].Should().BeEquivalentTo("  value pos. 0       Define a long value here.");
+            // Teardown
+        }
+        [Fact]
+        public void HelpText_wit_by_default_should_include_help_version_option()
+        {
+            // Fixture setup
+            // Exercize system 
+            var sut = new HelpText ()
+                .AddOptions(new NotParsed<Simple_Options>(TypeInfo.Create(typeof(Simple_Options)),
+                    Enumerable.Empty<Error>()));
+
+            // Verify outcome
+
+            var lines = sut.ToString().ToNotEmptyLines();
+            lines.Should().HaveCount(c => c ==7);
+            lines.Should().Contain("  help               Display more information on a specific command.");
+            lines.Should().Contain("  version            Display version information.");
+            // Teardown
+        }
+
+        [Fact]
+        public void HelpText_wit_AutoHelp_false_should_hide_help_option()
+        {
+            // Fixture setup
+            // Exercize system 
+            var sut = new HelpText { AutoHelp = false,AutoVersion = false}
+                .AddOptions(new NotParsed<Simple_Options>(TypeInfo.Create(typeof(Simple_Options)),
+                    Enumerable.Empty<Error>()));
+
+            // Verify outcome
+
+            var lines = sut.ToString().ToNotEmptyLines();
+            lines.Should().HaveCount(c => c ==5);
+            lines.Should().NotContain("  help               Display more information on a specific command.");
+            lines.Should().NotContain("  version            Display version information.");
+            // Teardown
+        }
+    }
+}