SymbolResult.FindResultFor

Author: jonsequitur

src/System.CommandLine.Tests/ArgumentTests.cs

@@ -297,6 +297,41 @@ public void Option_ArgumentResult_parentage_to_root_symbol_is_set_correctly_when
                     .Should()
                     .Be(command);
             }
+            
+            [Theory]
+            [InlineData("-x value-x -y value-y")]
+            [InlineData("-y value-y -x value-x")]
+            public void Symbol_can_be_found_without_explicitly_traversing_result_tree(string commandLine)
+            {
+                SymbolResult resultForOptionX = null;
+                var optionX = new Option<string>(
+                    "-x",
+                    parseArgument: _ => string.Empty);
+                
+                var optionY = new Option<string>(
+                    "-y",
+                    parseArgument: argResult =>
+                    {
+                        resultForOptionX = argResult.FindResultFor(optionX);
+                        return string.Empty;
+                    });
+            
+                var command = new Command("the-command")
+                {
+                    optionX,
+                    optionY,
+                };
+            
+                command.Parse(commandLine);
+
+                resultForOptionX
+                    .Should()
+                    .BeOfType<OptionResult>()
+                    .Which
+                    .Option
+                    .Should()
+                    .BeSameAs(optionX);
+            }
 
             [Fact]
             public void Command_ArgumentResult_Parent_is_set_correctly_when_token_is_implicit()

src/System.CommandLine/Parsing/ParseResultVisitor.cs

@@ -325,7 +325,7 @@ private void PopulateDefaultValues()
             {
                 foreach (var symbol in commandResult.Command.Children)
                 {
-                    var symbolResult = _rootCommandResult!.FindResultFor(symbol);
+                    var symbolResult = _rootCommandResult!.FindResultForSymbol(symbol);
 
                     if (symbolResult is null)
                     {

src/System.CommandLine/Parsing/RootCommandResult.cs

@@ -47,7 +47,7 @@ private void EnsureResultMapsAreInitialized()
             }
         }
 
-        public ArgumentResult? FindResultFor(IArgument argument)
+        public override ArgumentResult? FindResultFor(IArgument argument)
         {
             EnsureResultMapsAreInitialized();
 
@@ -56,7 +56,7 @@ private void EnsureResultMapsAreInitialized()
             return result;
         }
 
-        public CommandResult? FindResultFor(ICommand command)
+        public override CommandResult? FindResultFor(ICommand command)
         {
             EnsureResultMapsAreInitialized();
 
@@ -65,7 +65,7 @@ private void EnsureResultMapsAreInitialized()
             return result;
         }
 
-        public OptionResult? FindResultFor(IOption option)
+        public override OptionResult? FindResultFor(IOption option)
         {
             EnsureResultMapsAreInitialized();
 
@@ -74,7 +74,7 @@ private void EnsureResultMapsAreInitialized()
             return result;
         }
 
-        public SymbolResult? FindResultFor(ISymbol symbol)
+        public SymbolResult? FindResultForSymbol(ISymbol symbol)
         {
             switch (symbol)
             {

src/System.CommandLine/Parsing/SymbolResult.cs

@@ -27,7 +27,13 @@ private protected SymbolResult(
 
         public SymbolResult? Parent { get; }
 
-        internal virtual RootCommandResult? Root => (Parent as CommandResult)?.Root;
+        internal virtual RootCommandResult? Root =>
+            Parent switch
+            {
+                CommandResult c => c.Root,
+                OptionResult o => o.Parent?.Root,
+                _ => null
+            };
 
         public ISymbol Symbol { get; }
 
@@ -65,6 +71,15 @@ protected internal ValidationMessages ValidationMessages
 
         internal void AddToken(Token token) => _tokens.Add(token);
 
+        public virtual ArgumentResult? FindResultFor(IArgument argument) =>
+            Root?.FindResultFor(argument);
+
+        public virtual CommandResult? FindResultFor(ICommand command) =>
+            Root?.FindResultFor(command);
+
+        public virtual OptionResult? FindResultFor(IOption option) =>
+            Root?.FindResultFor(option);
+
         internal ArgumentResult GetOrCreateDefaultArgumentResult(Argument argument) =>
             _defaultArgumentValues.GetOrAdd(
                 argument,