Unhelpful/misleading error message when inporting fails due to missing dependency #1859

Activity

1. slozier commented on Jan 4, 2025

   

   slozier

   on Jan 4, 2025

   Contributor

   More actions

   I tried to reproduce this but without success. Perhaps I'm missing something (or not following the repro steps properly)?

   Here's my C# library:

   using Newtonsoft.Json;
   
   namespace Issue1859;
   
   public class Class1<T>
   {
       public virtual JsonTextWriter? Writer {get;}
   }
   
   public class Class2 : Class1<string> { }

   Then in IronPython I can import Class2 without issues. If I try to use it I do get a FileNotFoundError with the expected error message:

   FileNotFoundError: [Errno 2] Could not load file or assembly 'Newtonsoft.Json, Version=13.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed'. The system cannot find the file specified.

   Any suggestions to try and break it?
2. LeeReid1 commented on Jan 5, 2025

   

   LeeReid1

   on Jan 5, 2025

   Last edited by LeeReid1

   Author

   More actions

   Hey,

   Thanks for taking a look into it.

   I have since altered the code that lead to that exact example and not kept the old version, but something similar is as follows.

   C# Code. TorchSharp is a NuGet package. Canary is there for a sanity check.

   namespace FlipProof.Torch;
   
   public class Canary { }
   
   public abstract class BobBase
   {
      [CLSCompliant(false)]
      public TorchSharp.Reduce MyProperty { get; init; }
   }
   
   
   public sealed class Bob : BobBase
   { }
   

   Publish then and delete the torchsharp dll or, I suppose, just build the code and check torchsharp hasn't been copied into the bin dir.

   Then in python

   import clr
   import sys
   import os
   
   csharpLibraryDir = path-to-the-bin-dir-for-c#
   sys.path.append(csharpLibraryDir)
   clr.AddReferenceToFileAndPath("FlipProof.Torch")
   
   from FlipProof.Torch import Canary # Passes
   from FlipProof.Torch import Bob # ImportError: Cannot import name Bob
   from FlipProof.Torch import BobBase # ImportError: Cannot import name BobBase
   

   then call
   ipy <name of your python file>

   Some important notes:

   • both the child and base classes fail to import here, which differs from my initial report. Both have been seen.
   • In this example, virtual doesn't make a difference. In my other code, removing virtual solved the issue
   • I have an example that will fail in the way I said originally but the codebase is much more complicated and so I don't think it's a good starting point...
   • If torch.Size is changed to a reference type, no error occurs