Fixes #776

src/CommandLine/Core/Tokenizer.cs

@@ -86,29 +86,32 @@ static class Tokenizer
             return Result.Succeed(exploded as IEnumerable<Token>, tokenizerResult.SuccessMessages());
         }
 
+        /// <summary>
+        /// Normalizes the given <paramref name="tokens"/>.
+        /// </summary>
+        /// <returns>The given <paramref name="tokens"/> minus all names, and their value if one was present, that are not found using <paramref name="nameLookup"/>.</returns>
         public static IEnumerable<Token> Normalize(
             IEnumerable<Token> tokens, Func<string, bool> nameLookup)
         {
-            var indexes =
+            var toExclude =
                 from i in
                     tokens.Select(
                         (t, i) =>
                         {
-                            var prev = tokens.ElementAtOrDefault(i - 1).ToMaybe();
-                            return t.IsValue() && ((Value)t).ExplicitlyAssigned
-                                   && prev.MapValueOrDefault(p => p.IsName() && !nameLookup(p.Text), false)
-                                ? Maybe.Just(i)
-                                : Maybe.Nothing<int>();
+                            if (t.IsName() == false
+                                || nameLookup(t.Text))
+                            {
+                                return Maybe.Nothing<Tuple<Token, Token>>();
+                            }
+
+                            var next = tokens.ElementAtOrDefault(i + 1).ToMaybe();
+                            var removeValue = next.MatchJust(out var nextValue)
+                                              && next.MapValueOrDefault(p => p.IsValue() && ((Value)p).ExplicitlyAssigned, false);
+                            return Maybe.Just(new Tuple<Token, Token>(t, removeValue ? nextValue : null));
                         }).Where(i => i.IsJust())
                 select i.FromJustOrFail();
 
-            var toExclude =
-                from t in
-                    tokens.Select((t, i) => indexes.Contains(i) ? Maybe.Just(t) : Maybe.Nothing<Token>())
-                        .Where(t => t.IsJust())
-                select t.FromJustOrFail();
-
-            var normalized = tokens.Where(t => toExclude.Contains(t) == false);
+            var normalized = tokens.Where(t => toExclude.Any(e => ReferenceEquals(e.Item1, t) || ReferenceEquals(e.Item2, t)) == false);
 
             return normalized;
         }

tests/CommandLine.Tests/Unit/Core/TokenizerTests.cs

@@ -62,12 +62,12 @@ public void Explode_scalar_with_separator_in_even_args_input_returns_sequence()
         }
 
         [Fact]
-        public void Normalize_should_remove_all_value_with_explicit_assignment_of_existing_name()
+        public void Normalize_should_remove_all_names_and_values_with_explicit_assignment_of_non_existing_names()
         {
             // Fixture setup
             var expectedTokens = new[] {
-                Token.Name("x"), Token.Name("string-seq"), Token.Value("aaa"), Token.Value("bb"),
-                Token.Name("unknown"), Token.Name("switch") };
+                Token.Name("x"), Token.Name("string-seq"), Token.Value("value0", true), Token.Value("bb"),
+                Token.Name("switch") };
             Func<string, bool> nameLookup =
                 name => name.Equals("x") || name.Equals("string-seq") || name.Equals("switch");
 
@@ -78,7 +78,7 @@ public void Normalize_should_remove_all_value_with_explicit_assignment_of_existi
                         Enumerable.Empty<Token>()
                             .Concat(
                                 new[] {
-                                    Token.Name("x"), Token.Name("string-seq"), Token.Value("aaa"), Token.Value("bb"),
+                                    Token.Name("x"), Token.Name("string-seq"), Token.Value("value0", true), Token.Value("bb"),
                                     Token.Name("unknown"), Token.Value("value0", true), Token.Name("switch") })
                     //,Enumerable.Empty<Error>()),
                     , nameLookup);
@@ -89,6 +89,34 @@ public void Normalize_should_remove_all_value_with_explicit_assignment_of_existi
             // Teardown
         }
 
+        [Fact]
+        public void Normalize_should_remove_all_names_of_non_existing_names()
+        {
+            // Fixture setup
+            var expectedTokens = new[] {
+                Token.Name("x"), Token.Name("string-seq"), Token.Value("value0", true), Token.Value("bb"),
+                Token.Name("switch") };
+            Func<string, bool> nameLookup =
+                name => name.Equals("x") || name.Equals("string-seq") || name.Equals("switch");
+
+            // Exercize system
+            var result =
+                Tokenizer.Normalize(
+                    //Result.Succeed(
+                    Enumerable.Empty<Token>()
+                        .Concat(
+                            new[] {
+                                Token.Name("x"), Token.Name("string-seq"), Token.Value("value0", true), Token.Value("bb"),
+                                Token.Name("unknown"), Token.Name("switch") })
+                    //,Enumerable.Empty<Error>()),
+                    , nameLookup);
+
+            // Verify outcome
+            result.Should().BeEquivalentTo(expectedTokens);
+
+            // Teardown
+        }
+
         [Fact]
         public void Should_properly_parse_option_with_equals_in_value()
         {

tests/CommandLine.Tests/Unit/Issue776Tests.cs

@@ -0,0 +1,36 @@
+using FluentAssertions;
+using Xunit;
+
+// Issue #776 and #797
+// When IgnoreUnknownArguments is used and there are unknown arguments with explicitly assigned values, other arguments with explicit assigned values should not be influenced.
+// The bug only occured when the value was the same for a known and an unknown argument.
+
+namespace CommandLine.Tests.Unit
+{
+    public class Issue776Tests
+    {
+        [Theory]
+        [InlineData("3")]
+        [InlineData("4")]
+        public void IgnoreUnknownArguments_should_work_for_all_values(string dummyValue)
+        {
+            var arguments = new[] { "--cols=4", $"--dummy={dummyValue}" };
+            var result = new Parser(with => { with.IgnoreUnknownArguments = true; })
+                .ParseArguments<Options>(arguments);
+
+            Assert.Empty(result.Errors);
+            Assert.Equal(ParserResultType.Parsed, result.Tag);
+
+            result.WithParsed(options =>
+            {
+                options.Cols.Should().Be(4);
+            });
+        }
+
+        private class Options
+        {
+            [Option("cols", Required = false)]
+            public int Cols { get; set; }
+        }
+    }
+}