Update version

Changelog.md

@@ -1,3 +1,7 @@
+### v2.0.6 (17-Jul-2021)
+
+- Fixed an issue where an exception thrown via reflection during parameter or option binding resulted in `Exception has been thrown by the target of an invocation` error instead of a more useful message. Such exceptions will now be unwrapped to provide better user experience.
+
 ### v2.0.5 (09-Jul-2021)
 
 - Fixed an issue where calling `IConsole.Output.Encoding.EncodingName` and some other members threw an exception.

CliFx.Tests/ConsoleSpecs.cs

@@ -1,6 +1,9 @@
 using System;
 using System.Collections.Generic;
+using System.IO;
+using System.Text;
 using System.Threading.Tasks;
+using CliFx.Infrastructure;
 using CliFx.Tests.Utils;
 using CliWrap;
 using CliWrap.Buffered;
@@ -135,5 +138,22 @@ public class Command : ICommand
             stdOut.Trim().Should().Be("Hello world");
             stdErr.Trim().Should().Be("Hello world");
         }
+
+        [Fact]
+        public void Console_does_not_emit_preamble_when_used_with_encoding_that_has_it()
+        {
+            // Arrange
+            using var buffer = new MemoryStream();
+            using var consoleWriter = new ConsoleWriter(FakeConsole, buffer, Encoding.UTF8);
+
+            // Act
+            consoleWriter.Write("Hello world");
+            consoleWriter.Flush();
+
+            var output = consoleWriter.Encoding.GetString(buffer.ToArray());
+
+            // Assert
+            output.Should().Be("Hello world");
+        }
     }
 }

CliFx.Tests/ConversionSpecs.cs

@@ -946,5 +946,48 @@ public class Command : ICommand
             exitCode.Should().NotBe(0);
             stdErr.Should().Contain("Hello world");
         }
+
+        [Fact]
+        public async Task Parameter_or_option_value_conversion_fails_if_the_static_parse_method_throws()
+        {
+            // Arrange
+            var commandType = DynamicCommandBuilder.Compile(
+                // language=cs
+                @"
+public class CustomType
+{
+    public string Value { get; }
+    
+    private CustomType(string value) => Value = value;
+    
+    public static CustomType Parse(string value) => throw new Exception(""Hello world"");
+}
+
+[Command]
+public class Command : ICommand
+{
+    [CommandOption('f')]
+    public CustomType Foo { get; set; }
+    
+    public ValueTask ExecuteAsync(IConsole console) => default;
+}
+");
+            var application = new CliApplicationBuilder()
+                .AddCommand(commandType)
+                .UseConsole(FakeConsole)
+                .Build();
+
+            // Act
+            var exitCode = await application.RunAsync(
+                new[] {"-f", "bar"},
+                new Dictionary<string, string>()
+            );
+
+            var stdErr = FakeConsole.ReadErrorString();
+
+            // Assert
+            exitCode.Should().NotBe(0);
+            stdErr.Should().Contain("Hello world");
+        }
     }
 }

CliFx/CommandBinder.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
+using System.Reflection;
 using CliFx.Exceptions;
 using CliFx.Extensibility;
 using CliFx.Infrastructure;
@@ -161,12 +162,18 @@ namespace CliFx
             }
             catch (Exception ex) when (ex is not CliFxException) // don't wrap CliFxException
             {
+                // We use reflection-based invocation which can throw TargetInvocationException.
+                // Unwrap these exceptions to provide a more user-friendly error message.
+                var errorMessage = ex is TargetInvocationException invokeEx
+                    ? invokeEx.InnerException?.Message ?? invokeEx.Message
+                    : ex.Message;
+
                 throw CliFxException.UserError(
                     $"{memberSchema.GetKind()} {memberSchema.GetFormattedIdentifier()} cannot be set from provided argument(s):" +
                     Environment.NewLine +
                     rawValues.Select(v => '<' + v + '>').JoinToString(" ") +
                     Environment.NewLine +
-                    $"Error: {ex.Message}",
+                    $"Error: {errorMessage}",
                     ex
                 );
             }

Directory.Build.props

@@ -1,7 +1,7 @@
 <Project>
 
   <PropertyGroup>
-    <Version>2.0.5</Version>
+    <Version>2.0.6</Version>
     <Company>Tyrrrz</Company>
     <Copyright>Copyright (C) Alexey Golub</Copyright>
     <LangVersion>latest</LangVersion>