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NuGet; Transitive Dependencies; Binding Redirect Hell

.NETCore just litters your disk a lot worse, too many versions, too many assemblies, too many standards and no GAC. Hopefully they'll get their act together sometime soon. – Hans Passant Aug 17 '17 at 10:37
No, it just keeps getting worse.   : \
Have a .NET Standard 2.0 class library that references Microsoft extension classes. When we deploy to the server, we get runtime binding exceptions. My questions first:
Why aren't binding redirects being generated for transitive dependencies?
Since they're not, how do I come up with a full list to add manually?
How does the compiler know what version to redirect to unless it intends for me to deploy the version it compiled against?
How do I come up with a list of DLLs to deploy - excluding framework DLLs but including anything that wouldn't be on the server?
Is a nuget package broken if the assembly version in \ref\ is lower than the assembly version in \lib\?
Details:
We have a class library compiling against .NET Standard 2.0... it references Microsoft.Extensions.Configuration.Json.
MimExtension
\--Dependendencies
\--Packages
\--Microsoft.Extensions.Configuration.Json (5.0.0)
\--System.Text.Json (5.0.0)
\--System.Buffers (4.5.1)
System.Buffers resolves to \.nuget\packages\system.buffers\4.5.1\ref\netstandard2.0\System.Buffers.dll. The file version in that directory is 4.6.28619.1, date 2020/02/19. .NET Reflector shows the assembly version as 4.0.2.0.
The \lib\ version of that DLL is \.nuget\packages\system.buffers\4.5.1\lib\netstandard2.0\System.Buffers.dll... same file version and date, but the assembly version is 4.0.3.0.
Compiling the DLL gives me a .dll.config file with binding redirects that I could copy into the consuming application's app.config - but System.Buffers.dll and System.Text.Json.dll aren't there. Microsoft.Extensions.Configuration.Json.dll also isn't there - though another nuget package, Microsoft.Extensions.Configuration.Abstractions.dll, is.
I'm assuming this means the compiler thinks no redirect is necessary for the DLLs that aren't in there (see question #3). It makes sense that only DLLs with conflicts across references get added to the binding redirects (if that's what's happening), but conflict or not, our app won't bind to the \lib\ version of the System.Buffers.dll the compiler uses and RTE's (question #1).
To resolve this I can add binding redirects manually. But how do I look at all the nuget references in my project and determine (recursively) what version was chosen for each dll? Short of dumping verbose build output to a text file with some fancy regex and an hour of copy and paste, that is (question #2).
Note: I can add <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies> to the .csproj file and get all referenced dlls dumped to the output directory - including .NET dlls like System.Threading.dll and System.Runtime.CompilerServices.Unsafe.dll- but that still doesn't get me a full list of what versions each one are... especially since I need assembly versions, which I can't even display in explorer.
Regarding that... some of the binding redirects generated automatically are for .NET assemblies like System.Threading... does VS really expect me to deploy the version of System.Threading I compiled against? For that dll, I have newVersion="4.0.11.0"... our server has assembly version 4.0.0.0, file version 4.8.3761.0. VS expects me to deploy assembly version 4.0.11.0, file version 1.0.24212.01 (wtff?!?). The 4.0.11.0 version pulled down by nuget is dated 2019/12/26... the 4.0.0.0 server version is dated 2021/01/21.
I'm guessing that's a Core vs. Framework versioning wtf - but binding redirects don't care. The app that will load our library is .NET Framework 4.8... am I supposed to deploy the System.Threading 4.0.11.0 dll with my app, or manually change the binding redirect and let it load the server's version? It's absolutely ludicrous that a core DLL has a higher assembly version than its newer .NET Framework counterpart (question #addingnewonesasigo).
So when we're referencing nuget packages, how do we know what needs deployed and what doesn't (or worse, shouldn't be)? (question #4) I feel like the build process should copy dlls that aren't part of the framework/won't be in the GAC to the output directory - but there's nothing TIAO to indicate that in the nuget package specs.
Regarding #5... shouldn't the dlls in a nuget package have the same version in the \ref\ and \lib\ folders? The breakdown in Microsoft.Extensions.Configuration.Json is in System.Text.Json... S.T.J's .nuspec lists a .NET Standard 2.0 dependency to <dependency id="System.Buffers" version="4.5.1" />. So why would the System.Buffers.dll nuget cache have different versions in \ref\ and \lib\? Shouldn't they both be either 4.0.2.0 or 4.0.3.0?
There are a lot of questions out there on this - even some specifically to System.Buffers. But nobody has resolved this satisfactorily (that I can find) for a class library. I'm going to try adding a scratch website to the solution and reference the library - just to see whether .NET gets the necessary dlls/redirects in place for its only love: Web
Update
I manually added a binding redirect to 4.0.3.0 for System.Buffers... and immediately got the next mole to whack: Could not load file or assembly 'System.Numerics.Vectors, Version=4.1.3.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies
And so it will go, until we find a way to list everything that VS probed. And without 100% regression coverage, there's no guarantee we won't miss something when we deploy.

For an executable, dotnet publish; and ship the resulting folder is always correct.
But for a dll compiled against .net standard; I've only had success building a nuget package and referencing it and letting the compiler (whole package thereof) figure out what final dlls the project needs. You can make a nuget package with dotnet pack.
I have never needed binding redirects to link .netstandard to .net framework.

Compiling the library for specific platforms pulls the dependent DLLs into the bin folder. This makes sense in retrospect - compiling for .NET Standard is only meaningful when the target platform isn't known and won't be chosen by the developer of the library. That scenario requires a centralized package manager.
Targeting for .NET 4.8 (highest version currently supported by MIM) gave us the DLLs in the bin directory and set binding redirects in the config file.
That said, the System.Buffers.DLL version issue only went away because the .NET 4.8 dependencies were defined correctly. The Microsoft.Extensions.Configuration.Json .nuspec indicates a different assembly version than the dll that gets downloaded when compiling for .NET Standard 2.0. I don't know if that's an issue with the references when the .NET developers compiled the nuget package or an unavoidable artifact of nuget packaging itself.

Could not load dll from GAC in .NetCore Application

My sample console application (say App1) developed using .Net Core 3.1 and it calls another .NetCore dll (Say Dll1). I have added as reference dll with "Copy Local = Yes". I am using Visual Studio 2019 as Dev environment.
It works fine in direct scenario. Means, when I set "Copy Local = Yes" in App1.
I have registered that .Net Core dll (Dll1) in GAC and set "Copy Local = No" in App1.
Now I could not load .Net Core (Dll1) and it throws below exception.
Unhandled exception. System.IO.FileNotFoundException: Could not load file or assembly 'xxxxx, Version=1.0.0.0, Culture=neutral, PublicKeyToken=66f432805192946d'. The system cannot find the file specified.
File name: 'xxxxx, Version=1.0.0.0, Culture=neutral, PublicKeyToken=66f432805192946d'
at xxxxx.Program.Main(String[] args)
My doubts:
Whether .Net Core supports calling dll from GAC?
Kindly help me to resolve this issue.
Regards,
Hari

Your Question
Does .Net Core load assemblies from the Global Assembly Cache (GAC)?
The Short Answer:
Nope
The Long Answer:
When you use an assembly, with CopyLocal = false set, it means that the Assembly (.dll file) will not be placed into the output directory of whatever you just built.
Here, .Net Core acts differently than .Net Framework:
In .Net Framework
As soon as the missing assembly is used somewhere in your executing code, the runtime environment will try to search for it, find and load it. For .Net Framework, this happens in a very specific way, which includes loading it from the GAC (Global Assembly Cache) when available.
And this is how dotnetcore does:
Those dotnetcore apps are designed to be standalones and easy to handle, and do not want to rely on their environment. You deliver all they need to know along with them. So, those apps won't go searching around for missing dlls, and they will not look into the GAC. This is the normal deployment method, and this is called "self contained deployment"
There is, however, something called the runtime package store, that can help optimizing your deployment, by defining that your .Net Core Application is not "self containing", but is deployed against a defined "framework (= where a set of libraries are defined to be present). This is called "framework dependent deployment"
If you need more Information of Framework-Dependent Deployment of .Net Core Apps
Have a look at this
Is there any GAC equivalent for .NET Core?

'Could not load file or assembly 'netstandard, Version=2.0.0.0, ...'. Reference assemblies should not be loaded for execution

Goal:
From a .NET 4.7 console app, using reflection with Assembly.GetType(), I am trying extract the Type of a netstandard 2.0 class from Assembly X. Then I want to create an instance of this Type with Activator.CreateInstance().
What I am trying to do:
However, this assembly X has a dependency to netstandard 2.0. To be able to get the Type, netstandard dependency has to be loaded into the AppDomain. That's why when the AppDomain is requesting the netstandard assembly through the AssemblyResolve event, I simply load the dll like this :
var netStandardDllPath = #"C:\Users\xxx\.nuget\packages\NETStandard.Library.2.0.0-preview1-25301-01\build\netstandard2.0\ref\netstandard.dll";
return Assembly.LoadFrom(netStandardDllPath);
Which throws:
System.BadImageFormatException: 'Could not load file or assembly
'file:///C:\Users\vincent.lerouvillois.nuget\packages\NETStandard.Library.2.0.0-preview1-25301-01\build\netstandard2.0\ref\netstandard.dll'
or one of its dependencies. Reference assemblies should not be loaded
for execution. They can only be loaded in the Reflection-only loader
context. (Exception from HRESULT: 0x80131058)'
Inner Exception: BadImageFormatException: Cannot load a reference
assembly for execution.
What I know:
I know that they want us to load the DLL with Assembly.ReflectionOnlyLoadFrom. But doing that will prevent me from instanciate the type with Activator.CreateInstance(). See Microsoft official post
Also, I tried referencing the Nuget packages NETStandard.Library 2.0.0-preview1-25301-01 and NETStandard.Library.NETFramework 2.0.0-preview1-25305-02 in my console app so it would have the netstandard 2.0 libraries referenced, but it didn't change anything.
Question:
Does anyone would know if there is a proper way to load that dll without error, or maybe if this is a bug, or else? Or why this kind of dll is not able to load for execution?

The netstandard.dll you are trying to load is a reference assembly that which cannot be loaded for runtime on .NET Framework as pointed out by others. However if you need to resolve that dependency you will need to runtime version that maps to the framework you are trying to run on.
For .NET Standard support we are including them as part of the msbuild extensions that ship with VS so you will want to get the version of netstandard.dll from there. Depending on which version of VS2017 you have installed it should be somewhere like C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\MSBuild\Microsoft\Microsoft.NET.Build.Extensions\net461\lib\netstandard.dll or from the .NET Core 2.0 SDK you can find it C:\Program Files\dotnet\sdk\2.0.0\Microsoft\Microsoft.NET.Build.Extensions\net461\lib\netstandard.dll
Try using one of those versions in your scenario.

Wow. I just spent several hours tracking the cause of this "could not load ... netstandard" error down.
For me, the problem was that my .NET Framework project (which references both .NET Framework and .NET Standard libraries) was built with .NET Framework 4.7.2 and the system where I was deploying and running it did not have 4.7.2 installed.
Deploying a very small Console project with the same basic structure and references and executing that in a Command window finally revealed the correct error, in a pop-up, that .NET Framework 4.7.2 was missing.
If you're struggling with this particular error, make sure you have the necessary .NET Framework installed.

Set Copy Local to true in netstandard.dll properties.
Open Solution Explorer and right click on netstandard.dll.
Set Copy Local to true.

You can't load a reference assembly.
.NET Standard is a collection of APIs that must be provided by .NET Standard compatible implementations.
A reference assembly only contains contracts. This means that it contains no implementation. The assembly you are trying to load contains the .NET Standard 2.0 contracts.
A contract looks like this: https://github.com/dotnet/standard/blob/master/netstandard/ref/mscorlib.cs
EDIT: .NET Framework 4.7 implements .NET Standard 2.0, so you shouldn't need to load any assembly to use Activator.CreateInstance() to instantiate a .NET Standard type.

NETStandard 2.0.0-preview1 in not compatibility with net461 and net47.
but for realese .NET Core SDK 2.0 assemblies (as well as 2.0.0-preview2)
var netStandardDllPath = #"c:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.netcore.app\2.0.0\ref\netcoreapp2.0\netstandard.dll";
Console.WriteLine(Assembly.LoadFrom(netStandardDllPath).FullName);
all is ok.
But if you steel need to load preview1 libraries, maybe you should to use netstandard2.0 instead net471.

For me solved doing the following:
1 - Installed latest .Net Framework on server.
2 - Updated windows server and my local machine.
3 - Went to Manage Nuget Package and updated all references on the update tab.
Perhaps only doing step 3 can solve in your case

In case if IBM Message Queue references are used in the project solution, this exception indicates that the DLL used for refering MQ classes are incompatible with the host(server) .NET version installed.
In this scenario, either we need to update server with latest update and make sure .NET latest version is available or use lower version of IBM Message queue DLL as reference.
Old version DLL - amqmdnet.dll (no new features will be introduced by IBM as not in support)
Latest version DLL - amqmdnetstd.dll (to run IBM MQ classes for .NET Standard, you must install Microsoft .NET Core)

Install NetStandard.Library 2.0.0.0 from NuGet , It works for me. when I downgrade .net framework 4.6.1 to 4.6.0

If you are having this issue for a project that used to work, try deleting the bin and obj folders since caching can cause this, too.

When using .Net Standard 1.4 in a library and .Net framework 4.6.1 in and application, unable to load file System.IO.FileSystem, Version=4.0.1.0

I have a solution that contains a library and 2 applications. The applications represent the same program, with one built to target the Windows App Store through UAP10 and the other built to target a Microsoft Windows PC using .Net Framework 4.6.1. I'm using Visual Studio 2017.
I set the library project target .Net standard 1.4.
I set the UWP application to target Windows 10 Aniversary Edition (10.0; Build 14393), Min version Windows 10 (10.0; Build 10586).
I set the generic Windows application to target .Net Framework 4.6.1.
The UWP version compiles and runs fine.
Initially, the .Net Framework 4.6.1 compiles and runs. However, when I make a call to File.Open from System.IO, I get the following error message:
System.IO.FileNotFoundException: 'Could not load file or assembly
'System.IO.FileSystem, Version=4.0.1.0, Culture=neutral,
PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The
system cannot find the file specified.'
The code block with File.Run is within the library code (.Net Standard 1.4). I'm not sure what is causing the problem. I thought that I could use .Net Standard 1.4 libraries within an application that references .Net Framework 4.6.1.
As a workaround, I tried installing the Nuget package for System.IO in the .Net Framework application. System.IO Version 4.0.1.0 is not even an option. There is a version 4.0.10, but it doesn't work when this Nuget package is installed.
So, how do I properly reference System.IO operations within a .Net Framework 4.6.1 application that references the System.IO code within a .Net Standard 1.4 library?

This usually happens with "classic" csproj projects when referenced projects require overwritten override system defined types but no binding redirects are present that set this up correctly. When installing all the packages into a .net framework app (e.g. NETStandard.Library or NETStandard.Library.NETFramework(for upcoming .NET Standard 2.0)), this should be done automatically.
To force generation of binding redirects, add this to the csproj file of the .NET Framework project (if it is an executable project, the second property should be irrelevant but it doesn't hurt):
<PropertyGroup>
<AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
<GenerateBindingRedirectsOutputType>true</GenerateBindingRedirectsOutputType>
</PropertyGroup>

Referencing a .NET Standard project from full .NET Framework

I have a .net standard 1.4 project which I am referencing via project reference from a .net 4.6.1 project.
When I run I get the following message:
System.IO.FileNotFoundException: 'Could not load file or assembly 'System.Threading.Thread,
Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or
one of its dependencies. The system cannot find the file specified.'
I can work around this by referencing the nuget package for System.Threading.Thread version 4.3.0. But for some reason this is actually version 4.0.1.0 which then means I need a binding redirect.
Adding a binding redirect gets me past this issue and onto the next one. Which is:
System.IO.FileNotFoundException: 'Could not load file or assembly
'System.IO.FileSystem, Version=4.0.1.0, Culture=neutral,
PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The
system cannot find the file specified.'
Do I need to manually add packages (and potentially binding redirects) for all of the dependencies of my .net standard packages? This doesn't seem to be what was sold. Whats the point of .net standard if I have to ship with all the assemblies it needs even through these are already included in the GAC in the .net framework I am targeting. I can't see how this can be sold as .net standard 1.4 is compatible with .net 4.6.1 if by compatible you mean as long as you don't use .net 4.6.1 BCL libraries.
The following issue seems to be related https://github.com/NuGet/Home/issues/4488
However I have tried the suggested work around there. Which is to add:
<RestoreProjectStyle>PackageReference</RestoreProjectStyle>
to the .net 4.6.1 project. I tried this and it made no difference.
UPDATE
After adding the following to my .net 4.6.1 project:
<PackageReference Include="Legacy2CPSWorkaround" Version="1.0.0">
<PrivateAssets>All</PrivateAssets>
</PackageReference>
I now have System.IO.FileSystem in my output directory however its the wrong version. It's 4.0.2.0. Again I can resolve this using an binding redirect but I shouldn't need to.
I don't know where this 4.0.2.0 dll came from because it's not in my packages folder so it can't have come from nuget?