Could not load file or assembly 'Microsoft.Build, Version=15.1.0.0'

[sim590]

As I have described here I'm having errors when trying to run omnisharp-roslyn on my project. Here is the log file:

omnisharp-roslyn.log

It has been 'anonymized'. I hope it is fine. Also, error messages are in french. I don't know how I can change them, sorry.

The project failing to load is configured for the .NET framework 4.8. When running, the following:

& "C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.8 Tools\gacutil.exe" /l Microsoft.Build.Framework

I am getting the following result:

Microsoft (R) .NET Global Assembly Cache Utility.  Version 4.0.30319.0
Copyright (c) Microsoft Corporation. Tous droits réservés.

Global Assembly Cache contient les assemblys suivants :
  Microsoft.Build.Framework, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL
  Microsoft.Build.Framework, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL
  Microsoft.Build.Framework, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL
  Microsoft.Build.Framework, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL

Nombre d'éléments = 4

The assembly should be there no? I may have also run:

& "C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.8 Tools\gacutil.exe" /i "C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Current\Bin\Microsoft.Build.Framework.dll"

However, it did not change anything.

I ran the following inside the directory containing the csproj of the project I'm trying to open and got:

SDK .NET (refl?tant tous les fichiers global.json)?:
 Version:   5.0.301
 Commit:    ef17233f86

Environnement d'ex?cution?:
 OS Name:     Windows
 OS Version:  10.0.17763
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\5.0.301\

Host (useful for support):
  Version: 5.0.7
  Commit:  556582d964

.NET SDKs installed:
  2.1.524 [C:\Program Files\dotnet\sdk]
  3.1.300 [C:\Program Files\dotnet\sdk]
  3.1.410 [C:\Program Files\dotnet\sdk]
  5.0.301 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.All 2.1.18 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.28 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.18 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.28 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.16 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.18 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.28 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.16 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.16 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.7 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET runtimes or SDKs:
  https://aka.ms/dotnet-download

I hope we can help me debug this.

Also

I have tried a few steps mentioned on my omnisharp-vim ticket.

I'm not sure if I'm on the right track or what I'm missing. I would really appreciate help on this.

[nickspoons]

A relevant detail I got from the OmniSharp log is that you appear to have Visual Studio 2019 installed, which I would have expected to take care of all msbuild requirements

[filipw]

Can you share the repro project?

[sim590]

A relevant detail I got from the OmniSharp log is that you appear to have Visual Studio 2019 installed, which I would have expected to take care of all msbuild requirements

Yes and I have no issue with building the project with Visual Studio 2019.

I must say that the project does have particular setup with some dlls found in some custom directories. Tell me if there's anything I can do to provide more information...

Can you share the repro project?

I'm sorry, I can't. Unfortunately, the project is proprietary.

[sim590]

I see that omnisharp lists places where it finds MSBuild DLLs:

[info]: OmniSharp.MSBuild.Discovery.MSBuildLocator
        Located 2 MSBuild instance(s)
            1: Visual Studio Professional 2019 16.6.30128.74 - "C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Current\Bin"
            2: StandAlone 16.11.0 - "C:\Users\sdesaulniers\AppData\Local\omnisharp-vim\omnisharp-roslyn\.msbuild\Current\Bin"

Is it possible to give omnisharp a list of directory where it can look for DLLs ? I have a bunch of places where the file may be so if I could add directories for omnisharp to look for, then it could may be fix my issue?

[nickspoons]

@sim590 you'll get a lot more detail about what omnisharp-roslyn is doing, and where it's currently looking for DLLs, if you enable debug logging. Do this by passing the --loglevel debug flag to the server, or from omnisharp-vim with this setting:

let g:OmniSharp_loglevel = 'debug'

As for configuring DLL locations, the various omnisharp-roslyn configuration options are described in this wiki article: Configuration Options. However, as far as I know these options are for locating MSBuild and associated runtime/sdk DLLs, and not for project references. @filipw may be able to confirm whether this is correct.

[sim590]

I've searched for 15.1.0.0 in the following folder:

​C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild

I put the results in this file: msbuild-15.1.0.0-references.txt

Is there something that comes out of the ordinary? May be I have some settings that omnisharp-roslyn picks up here while I wouldn't want it for compiling my project.

I got some info from my coworkers that we don't really use specifically Microsoft.Build.Framework 15.1.0.0. We shouldn't need it specifically from what I understand, so it seems like there's a setting that omnisharp-roslyn picks up and makes it use 15.1.0.0 for some reason, but I'm not sure what.

I have upgraded Visual Studio 2019 and I don't have it listing the assembly version 15.1.0.0 anymore:

Microsoft (R) .NET Global Assembly Cache Utility.  Version 4.0.30319.0
Copyright (c) Microsoft Corporation. Tous droits r?serv?s.

Global Assembly Cache contient les assemblys suivants?:
  Microsoft.Build.Framework, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL
  Microsoft.Build.Framework, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL
  Microsoft.Build.Framework, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL

Nombre d'?l?ments = 3

I'm not sure if it's worth something to bring that up, but in any case.

[sim590]

I have found that Visual Studio config files have some relative paths for referencing Microsoft.Build DLLs:

I suspect that this does not play nice with Omnisharp or Omnisharp on WSL2. I currently use @nickspoons' suggestion for making Omnisharp-vim work under WSL2:

OmniSharp/omnisharp-vim#706 (comment)

@nickspoons: could the working directory be altered at some point for Omnisharp (or one of its subprocess) so that this could happen?

[sim590]

May be the following is more relevant: