Fix Compilation error when string default arguments contain backslashes #138

Author: neuecc

sandbox/GeneratorSandbox/Program.cs

@@ -2,12 +2,11 @@
 using FilterShareProject;
 
 
+args = ["Output"];
 
 var app = ConsoleApp.Create();
 
-var v = new OtherProjectCommand();
-// app.Add("", v.Execute);
-app.Add<MyProjectCommand>();
+app.Add<MyCommands>();
 
 app.Run(args);
 
@@ -19,4 +18,24 @@ public void Execute(int x)
     {
         Console.WriteLine("Hello?");
     }
+}
+
+
+public class MyCommands
+{
+    [Command("Error1")]
+    public void Error1(string msg = @"\")
+    {
+        Console.WriteLine(msg);
+    }
+    [Command("Error2")]
+    public void Error2(string msg = "\\")
+    {
+        Console.WriteLine(msg);
+    }
+    [Command("Output")]
+    public void Output(string msg = @"\\")
+    {
+        Console.WriteLine(msg); // 「\」
+    }
 }

src/ConsoleAppFramework/Command.cs

@@ -292,7 +292,8 @@ public string DefaultValueToString(bool castValue = true, bool enumIncludeTypeNa
         }
         if (DefaultValue is string s)
         {
-            return "\"" + s + "\"";
+            // default string value is escaped in symbol so safe to use @
+            return "@\"" + s + "\"";
         }
         if (DefaultValue == null)
         {

tests/ConsoleAppFramework.GeneratorTests/RunTest.cs

@@ -121,4 +121,51 @@ public class Test
 """, "show --aaa foo --value 100", expected);
 
     }
+
+    [Fact]
+    public void StringEscape()
+    {
+        var code = """
+var app = ConsoleApp.Create();
+app.Add<MyCommands>();
+app.Run(args);
+
+public class MyCommands
+{
+    [Command("Error1")]
+    public void Error1(string msg = @"\")
+    {
+        Console.Write(msg);
+    }
+    [Command("Error2")]
+    public void Error2(string msg = "\\")
+    {
+        Console.Write(msg);
+    }
+    [Command("Output")]
+    public void Output(string msg = @"\\")
+    {
+        Console.Write(msg); 
+    }
+}
+""";
+
+        verifier.Execute(code, "Error1", @"\");
+        verifier.Execute(code, "Error2", "\\");
+        verifier.Execute(code, "Output", @"\\");
+
+        // lambda
+
+        verifier.Execute("""
+ConsoleApp.Run(args, (string msg = @"\") => Console.Write(msg));
+""", "", @"\");
+
+        verifier.Execute("""
+ConsoleApp.Run(args, (string msg = "\\") => Console.Write(msg));
+""", "", "\\");
+
+        verifier.Execute("""
+ConsoleApp.Run(args, (string msg = @"\\") => Console.Write(msg));
+""", "", @"\\");
+    }
 }