Custom DLL (CommandGathering.dll) Fails Compile-Time Namespace Resolution with //css_ref

[jeff-h64]

I built a minimalistic custom DLL from CommandGathering.cs that defines the namespace CommandPlugin and a class CommandGather with a public method Execute. When referencing this DLL in a separate program (Main.cs) using the conventional //css_ref CommandGathering.dll directive, the compiler fails to resolve the CommandPlugin namespace (error CS0246).

However, if I dynamically load the assembly using Assembly.LoadFrom, the namespace and its types are correctly discovered and usable. Other third-party DLLs referenced in the same manner compile and work as expected. I've verified the DLL is in the correct folder, built as a proper class library with public types, and targeted to the correct framework. Any guidance or fixes to resolve this discrepancy would be greatly appreciated.

Using cscs.exe version 4.9.3.0 and dotnet engine

Issue can be duplicated using these 2 files;
CommandGathering.cs (for the dll)
Main.cs (which uses css_ref/using and generates error CS0246)

CommandGathering.cs

// CommandGathering.cs
//css_engine dotnet
// build: cscs -cd CommandGathering.cs

using System;

namespace CommandPlugin
{
    public class CommandGather
    {		
        public void Execute(string[] args)
        {
            Console.WriteLine("CommandGathering executed!");
        }
    }
}

Main.cs

// Main.cs
//css_engine dotnet
// build/run: cscs -verbose Main.cs
//css_ref CommandGathering.dll

using CommandPlugin;

class Program
{
    static void Main()
    {
        var cmd = new CommandGathering();
        cmd.Execute(null);
    }
}

Build and Run - css_ref does not seem to resolve

C:\000\Test01>cscs Main.cs
Error: Specified file could not be compiled.

C:\000\Test01\Main.cs(6,7): error CS0246:  The type or namespace name 'CommandPlugin' could not be found (are you missing a using directive or an assembly reference?)
C:\000\Test01\Main.cs(6,7): error CS0246:  The type or namespace name 'CommandPlugin' could not be found (are you missing a using directive or an assembly reference?)


C:\000\Test01>

Build and Run - with verbose on

Note that build of Main shows under References that it located C:\000\Test01\CommandGathering.dll

C:\000\Test01>
C:\000\Test01>cscs -verbose -cd CommandGathering.cs
> ----------------
  Provider:
  Script engine: C:\000\Test01\cscs.dll
  Compiler engine: dotnet (C:\Program Files\dotnet\dotnet.exe)
  Console Encoding: Codepage - 437 (Codepage - 437) - system default
  CurrentDirectory: C:\000\Test01
  CurrentProcess: 10772
  NuGet manager: dotnet
  NuGet cache: C:\Users\jeff.hansen\.nuget\packages
  Script cache: C:\Users\jeff.hansen\AppData\Local\Temp\csscript.core\cache
  Executing: C:\000\Test01\CommandGathering.cs
  Hosting: InProcess
  Script arguments:
  SearchDirectories:
    0 - C:\000\Test01
    ------- (local dirs) -------
    ------- (dirs from cmd args) -------
    ------- (dirs from code) -------
    ------- (dirs from config) -------
    1 - C:\000\Test01\lib
    2 - C:\ProgramData\cs-script\commands
    3 - C:\ProgramData\cs-script\inc
    ------- (cs-script special dirs) -------
    4 - C:\Users\jeff.hansen\AppData\Local\Temp\csscript.core\cache\-1986072933
> ----------------

Compiling script...

  Precompilers:
   0 - CommandGathering.cs -> csscript.DefaultPrecompiler
           from C:\000\Test01\cscs.dll

  Output file:
       C:\000\Test01\CommandGathering.dll

  Files to compile:
   0 - C:\000\Test01\CommandGathering.cs
   1 - C:\Users\jeff.hansen\AppData\Local\Temp\csscript.core\cache\-1986072933\CommandGathering.attr.g.cs

  References:
   0 - System
   1 - System.Core
> ----------------
> ----------------
> ----------------
Building with dotnet engine...
Initialization time: 62.7517 msec
Compilation time:    2257.6338 msec
Total load time:     2372.4822 msec
> ----------------

Created: C:\000\Test01\CommandGathering.dll

C:\000\Test01>
C:\000\Test01>cscs -verbose Main.cs
> ----------------
  Provider:
  Script engine: C:\000\Test01\cscs.dll
  Compiler engine: dotnet (C:\Program Files\dotnet\dotnet.exe)
  Console Encoding: Codepage - 437 (Codepage - 437) - system default
  CurrentDirectory: C:\000\Test01
  CurrentProcess: 4236
  NuGet manager: dotnet
  NuGet cache: C:\Users\jeff.hansen\.nuget\packages
  Script cache: C:\Users\jeff.hansen\AppData\Local\Temp\csscript.core\cache
  Executing: C:\000\Test01\Main.cs
  Hosting: InProcess
  Script arguments:
  SearchDirectories:
    0 - C:\000\Test01
    ------- (local dirs) -------
    ------- (dirs from cmd args) -------
    ------- (dirs from code) -------
    ------- (dirs from config) -------
    1 - C:\000\Test01\lib
    2 - C:\ProgramData\cs-script\commands
    3 - C:\ProgramData\cs-script\inc
    ------- (cs-script special dirs) -------
    4 - C:\Users\jeff.hansen\AppData\Local\Temp\csscript.core\cache\-1986072933
> ----------------

Compiling script...

  Precompilers:
   0 - Main.cs -> csscript.DefaultPrecompiler
           from C:\000\Test01\cscs.dll

  Output file:
       C:\Users\jeff.hansen\AppData\Local\Temp\csscript.core\cache\-1986072933\Main.cs.dll

  Files to compile:
   0 - C:\000\Test01\Main.cs
   1 - C:\Users\jeff.hansen\AppData\Local\Temp\csscript.core\cache\-1986072933\Main.attr.g.cs

  References:
   0 - System.Core
   1 - C:\000\Test01\CommandGathering.dll
   2 - System
> ----------------
Error: Specified file could not be compiled.

C:\000\Test01\Main.cs(6,7): error CS0246:  The type or namespace name 'CommandPlugin' could not be found (are you missing a using directive or an assembly reference?)
C:\000\Test01\Main.cs(6,7): error CS0246:  The type or namespace name 'CommandPlugin' could not be found (are you missing a using directive or an assembly reference?)

C:\000\Test01>
C:\000\Test01>

For comparison the functioning of the dll can be verified using;
MainLoad.cs (which uses Assembly.LoadFrom)

MainLoad.cs

// MainLoad.cs
//css_engine dotnet
// build/run: cscs -verbose MainLoad.cs

using System.Reflection;

class Program
{
    static void Main(string[] args)
    {
        // Load the assembly from file.
        var asm = Assembly.LoadFrom("CommandGathering.dll");

        Console.WriteLine("Loaded: " + asm.FullName);
        var type = asm.GetType("CommandPlugin.CommandGather");
        var cmd = Activator.CreateInstance(type);
        type.GetMethod("Execute").Invoke(cmd, new object[] { null });

        // Optional
        DisplayAssemblyInfo(asm);
    } // Main

    static void DisplayAssemblyInfo(Assembly asm)
    {
		Console.WriteLine("============================================================");
		Console.WriteLine("Assembly Information");
        Console.WriteLine($"Full Name : {asm.FullName}");
        Console.WriteLine($"Version   : {asm.GetName().Version}");
        Console.WriteLine($"Location  : {asm.Location}");

        // List all defined types and methods.
 		Console.WriteLine();
		Console.WriteLine("\nDefined Types:");
        foreach (var type in asm.GetTypes())
        {
            Console.WriteLine(" - " + type.FullName);
			ListMethods(type);
        }

        // List all referenced assemblies.
  		Console.WriteLine();
		Console.WriteLine("Referenced Assemblies:");
        foreach (var refAsm in asm.GetReferencedAssemblies())
        {
            Console.WriteLine(" - " + refAsm.FullName);
        }

        // List manifest resource names.
		Console.WriteLine();
		Console.WriteLine("Manifest Resources:");
        foreach (var resource in asm.GetManifestResourceNames())
        {
            Console.WriteLine($" - {resource}");
        }

        // List any custom attributes at the assembly level.
 		Console.WriteLine();
		Console.WriteLine("Custom Attributes:");
        foreach (var attribute in asm.GetCustomAttributes(false))
        {
            Console.WriteLine($" - {attribute.GetType().Name}");
        }
 		Console.WriteLine("============================================================");
   } // DisplayAssemblyInfo
	
	static void ListMethods(Type type)
    {
        Console.WriteLine($"   Methods in {type.FullName}:");

        // Get all public instance and static methods.
///        MethodInfo[] methods = type.GetMethods(BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static);
        MethodInfo[] methods = type.GetMethods(BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static | BindingFlags.DeclaredOnly);
      
        foreach (var method in methods)
        {
            Console.WriteLine($"    - {method.Name}");
        }
    } // ListMethods
}

Dynamic loading of dll can access namespace/class

C:\000\Test01>
C:\000\Test01>cscs MainLoad.cs
Loaded: CommandGathering, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null
CommandGathering executed!
============================================================
Assembly Information
Full Name : CommandGathering, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null
Version   : 1.0.0.0
Location  : C:\000\Test01\CommandGathering.dll


Defined Types:
 - CommandPlugin.CommandGather
   Methods in CommandPlugin.CommandGather:
    - Execute

Referenced Assemblies:
 - System.Runtime, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
 - System.Console, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a

Manifest Resources:

Custom Attributes:
 - CompilationRelaxationsAttribute
 - RuntimeCompatibilityAttribute
 - DebuggableAttribute
 - AssemblyDescriptionAttribute
 - TargetFrameworkAttribute
 - AssemblyCompanyAttribute
 - AssemblyConfigurationAttribute
 - AssemblyFileVersionAttribute
 - AssemblyInformationalVersionAttribute
 - AssemblyProductAttribute
 - AssemblyTitleAttribute
============================================================
C:\000\Test01>

[oleg-shilo]

Looking into it.
Thank you for such a detailed test case

[oleg-shilo]

You have a type there in the main:

var cmd = new CommandGathering(); // compile error
var cmd = new CommandGather();    // compile OK

When I changed it it started working

[jeff-h64]

CommandGathering vs CommandGather is indeed an error however when I corrected it it did not change the result for me. The compile error is still reported on line 6 at the 'using'.

C:\000\Test01>
C:\000\Test01>
C:\000\Test01>type Main.cs
// Main.cs
//css_engine dotnet
// build/run: cscs -verbose Main.cs
//css_ref CommandGathering.dll

using CommandPlugin;

class Program
{
    static void Main()
    {
        var cmd = new CommandGather();
        cmd.Execute(null);
    }
}

C:\000\Test01>
C:\000\Test01>cscs Main.cs
Error: Specified file could not be compiled.

C:\000\Test01\Main.cs(6,7): error CS0246:  The type or namespace name 'CommandPlugin' could not be found (are you missing a using directive or an assembly reference?)
C:\000\Test01\Main.cs(6,7): error CS0246:  The type or namespace name 'CommandPlugin' could not be found (are you missing a using directive or an assembly reference?)

Even if I comment out the body of Main() (lines 12&13) I will still get the error on line 6. I am extremely confused by this.

C:\000\Test01>
C:\000\Test01>type Main.cs
// Main.cs
//css_engine dotnet
// build/run: cscs -verbose Main.cs
//css_ref CommandGathering.dll

using CommandPlugin;

class Program
{
    static void Main()
    {
   //     var cmd = new CommandGather();
   //     cmd.Execute(null);
    }
}

C:\000\Test01>cscs Main.cs
Error: Specified file could not be compiled.

C:\000\Test01\Main.cs(6,7): error CS0246:  The type or namespace name 'CommandPlugin' could not be found (are you missing a using directive or an assembly reference?)
C:\000\Test01\Main.cs(6,7): error CS0246:  The type or namespace name 'CommandPlugin' could not be found (are you missing a using directive or an assembly reference?)

C:\000\Test01>

[oleg-shilo]

I believe that your //css_ref does not reference the assembly.

Let's establish if the error is caused by the script content (e.g. more typos), your environment or a cs-script defect.

I have attached the complete working sample (your sample in fact). If you execute the included run.cmd I expect it to work OK. If not, send me the produced .dll. I want to ensure that it has the content that we expect.

This is my test record:

[jeff-h64]

I did not see any files associated with your last response but looking at your screen recording I executed these commands to show the contents of the 2 source files and the css steps I saw that you performed. The CS0246 error when compiling main.cs is still occurring for me.

type CommandGathering.cs
type Main.cs
css
css -cd CommandGathering
css Main

The resulting dll and source file are attached below.

Issue406-1.zip

I noticed a few differences in the response from css. No install directory for me. Engine and Launcher reported cscs.exe not css.exe even though I executed css

• Install dir:
• Script engine: C:\000\Test01\cscs.dll
• Launcher: C:\000\Test01\cscs.exe

C:\000\Test01>type CommandGathering.cs
// CommandGathering.cs
//css_engine dotnet
// build: cscs -cd CommandGathering.cs

using System;

namespace CommandPlugin
{
    public class CommandGather
    {
        public void Execute(string[] args)
        {
            Console.WriteLine("CommandGathering executed!");
        }
    }
}

C:\000\Test01>type Main.cs
// Main.cs
//css_engine dotnet
// build/run: cscs -verbose Main.cs
//css_ref CommandGathering.dll

using CommandPlugin;

class Program
{
    static void Main()
    {
        var cmd = new CommandGather();
        cmd.Execute(null);
    }
}

C:\000\Test01>css
C# Script execution engine (.NET Core). Version 4.9.3.0.
Copyright (C) 2004-2023 Oleg Shilo. www.csscript.net (github.com/oleg-shilo/cs-script)

   CLR:             9.0.2
   System:          Microsoft Windows NT 10.0.19045.0
   Architecture:    x64
   Install dir:     <not integrated>
   Script engine:   C:\000\Test01\cscs.dll
   Launcher:        C:\000\Test01\cscs.exe
   Compiler engine: dotnet (C:\Program Files\dotnet\dotnet.exe)
   NuGet manager:   dotnet
   NuGet cache:     C:\Users\jeff.hansen\.nuget\packages
   Script cache:    C:\Users\jeff.hansen\AppData\Local\Temp\csscript.core\cache
   Custom commands: C:\ProgramData\cs-script\commands
   Global includes: C:\ProgramData\cs-script\inc


C:\000\Test01>css -cd CommandGathering
Created: C:\000\Test01\CommandGathering.dll

C:\000\Test01>css Main
Error: Specified file could not be compiled.

C:\000\Test01\Main.cs(6,7): error CS0246:  The type or namespace name 'CommandPlugin' could not be found (are you missing a using directive or an assembly reference?) 
C:\000\Test01\Main.cs(6,7): error CS0246:  The type or namespace name 'CommandPlugin' could not be found (are you missing a using directive or an assembly reference?) 

C:\000\Test01>

[oleg-shilo]

And of course I forgot to attach the zip file 🤦

I tested your sample. It works just fine:

So it is something about the environment, not your code.

What if you install cs-script?

dotnet install -g cs-script.cli

[oleg-shilo]

I think I may have found the deep cause.

Can you try?

dotnet cscs.dll main

[oleg-shilo]

Yes, I am sure that fixed your problem.
Another workaround is not to have your ref assemblies located in the folder where the script engine is. This is what happens naturally when you have cs-script installed, not just extracted from the zip file.

The script engine has this deliberate constraint for the ref assemblies not being in the engine folder. I need to understand the reasoning for this old constraint so I can revoke it if it's no longer needed.

Until then please use the workaround above.