点网核心不一致

Question

I have a problem in my application that when GetCustomAttributes is called on the assembly Sigil v4.7, it throws an exception.

But this only occurs in a specific situation. If Sigil v4.7 is added via Jil v2.15.4 then it will happen.

If you add Sigil v4.7 directly it does not repro. Similarly if you add the latest version of Jil (v2.17.0), which still references Sigil v4.7, it does not repro.

I am stumped as to why, given the same dll, I would get different results.

Here is my test code:

using System.Diagnostics;
using System.Linq;
using System.Reflection;

namespace WindowsAssemblyTest
{
    class Program
    {
        static void Main(string[] args)
        {
            var sigilAssembly = AppDomain.CurrentDomain.GetAssemblies()
                                         .FirstOrDefault(x => x.FullName.Contains("Sigil"));

            try
            {
                var attrs = sigilAssembly?.GetCustomAttributes(typeof(AssemblyProductAttribute), false)
                                          .OfType<AssemblyProductAttribute>();

                Debug.WriteLine(">>>>>>  Success: " + sigilAssembly?.GetName());
            }
            catch (System.IO.FileNotFoundException exception)
            {
                Debug.WriteLine(">>>>>>  Failed: " + sigilAssembly?.GetName() + " with " + exception.Message);
            }

            // This is here so the compiler does not remove the reference to Sigil.
            var createReferenceToSigil = Sigil.OptimizationOptions.All;    
        }
    }
}

To recreate this issue, create a .net core console app and add the above code to the program.cs . Then add a NuGet reference to Jil v2.15.4 and run. The Debug window will show:

>>>>>> Failed: Sigil, Version=4.7.0.0, Culture=neutral, PublicKeyToken=2d06c3494341c8ab with Could not load file or assembly 'System.Runtime.InteropServices.PInvoke, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.

If you then upgrade to Jil v2.17.0 you will see this:

>>>>>> Success: Sigil, Version=4.7.0.0, Culture=neutral, PublicKeyToken=2d06c3494341c8ab

Why would the same version of the dll Sigil fail for one version of Jil and not for another?

Answer 1

I don't think the problem has anything to do with Sigil. As you mentioned in your comment, it finds Sigil just fine, but fails on GetCustomAttributes .

And that's the problem: GetCustomAttributes relies on System.Runtime.InteropServices.PInvoke .

So why can it find PInvoke when you're using Jil v2.17.0 but not v2.15.4?

Look at the dependencies of both Jil v2.17.0 and Jil v2.15.4 . The difference is that 2.17.0 supports .NETStandard 2.0, but v2.15.4 only supports .NETStandard 1.6.

It's hard to find something that nails this down as exactly the problem, but if you search for "System.Runtime.InteropServices.PInvoke" "GetCustomAttributes" you will find several results that explain that System.Runtime.InteropServices.PInvoke was not available in .NET Core 1.0. (it was in the release candidate, but removed before release )

So I believe what's happening is that if you use the newer package, it's running under .NETStandard 2.0 and PInvoke is available.