Fix issue with custom exception handler not triggering (#402)

Author: calebkiage

src/Program.cs

@@ -65,7 +65,30 @@ static async Task<int> Main(string[] args)
             }
 
             var builder = BuildCommandLine()
-                .UseDefaults()
+                .UseVersionOption()
+                .UseHelp()
+                .UseEnvironmentVariableDirective()
+                .UseParseDirective()
+                .UseSuggestDirective()
+                .RegisterWithDotnetSuggest()
+                .UseTypoCorrections()
+                .UseParseErrorReporting()
+                .CancelOnProcessTermination()
+                .UseExceptionHandler((ex, context) =>
+                {
+                    var message = GetExceptionMessage(ex);
+                    var exitCode = GetExceptionExitCode(ex);
+
+                    if (!string.IsNullOrEmpty(message))
+                    {
+                        Console.ResetColor();
+                        Console.ForegroundColor = ConsoleColor.Red;
+                        context.Console.Error.WriteLine(message);
+                        Console.ResetColor();
+                    }
+
+                    context.ExitCode = exitCode;
+                })
                 .UseHost(CreateHostBuilder)
                 .UseRequestAdapter(ic =>
                 {
@@ -91,9 +114,20 @@ static async Task<int> Main(string[] args)
                 ic.BindingContext.AddService(_ => host.Services.GetRequiredService<LogoutService>());
                 await next(ic);
             });
-            builder.UseExceptionHandler((ex, context) =>
+
+            try
             {
-                var message = ex switch
+                var parser = builder.Build();
+                return await parser.InvokeAsync(args);
+            }
+            finally
+            {
+                listener?.Dispose();
+            }
+        }
+
+        static string? GetExceptionMessage<E>(E ex) where E: Exception {
+            return ex switch
                 {
                     _ when ex is AuthenticationRequiredException => "Token acquisition failed. Run mgc login command first to get an access token.",
                     _ when ex is TaskCanceledException => string.Empty,
@@ -103,36 +137,15 @@ static async Task<int> Main(string[] args)
                     Identity.Client.MsalException e => $"Authentication failed: {e.Message}",
                     _ => ex.Message
                 };
+        }
 
-                var exitCode = ex switch
+        static int GetExceptionExitCode<E>(E ex) where E: Exception => ex switch
                 {
                     _ when ex is AuthenticationRequiredException => 1,
                     _ when ex is TaskCanceledException => 0,
                     _ => -1
                 };
 
-                if (!string.IsNullOrEmpty(message))
-                {
-                    Console.ResetColor();
-                    Console.ForegroundColor = ConsoleColor.Red;
-                    context.Console.Error.WriteLine(message);
-                    Console.ResetColor();
-                }
-
-                context.ExitCode = exitCode;
-            });
-
-            try
-            {
-                var parser = builder.Build();
-                return await parser.InvokeAsync(args);
-            }
-            finally
-            {
-                listener?.Dispose();
-            }
-        }
-
         static CommandLineBuilder BuildCommandLine()
         {
             var rootCommand = new GraphClient().BuildRootCommand();