A warning causes build to fail, but still says "0 Errors"

[itsho]

Steps to reproduce

Use the attached solution (.NET 4.0 Console app) - MsBuildComIssue_v1.zip

Or, create it manually:

1. Create a .NET project (I'm using WPF) with reference to a specific COM object MSHTML- "00020430-0000-0000-c000-000000000046" version 2.0.

2. make sure you are using a machine without Microsoft Office!

3. use msbuild to build the project.

In the log you can see that it will use the following "csc" command:

C:\Program Files (x86)\Microsoft Visual Studio\<yourVersion>\MSBuild\<yourVersion>\Bin\Roslyn\csc.exe 
	/noconfig 
	/nowarn:1701,1702 
	/nostdlib+ 
	/errorreport:prompt 
	/warn:4 
	/define:TRACE 
	/highentropyva-
	/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\Microsoft.CSharp.dll"
	/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\mscorlib.dll"
	/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\PresentationCore.dll"
	/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\PresentationFramework.dll"
	/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\System.Core.dll"
	/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\System.Data.DataSetExtensions.dll"
	/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\System.Data.dll"
	/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\System.dll"
	/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\System.Windows.Forms.dll"
	/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\System.Xaml.dll"
	/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\System.Xml.dll"
	/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\System.Xml.Linq.dll"
	/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\WindowsBase.dll" 
	/debug:pdbonly 
	/filealign:512 
	/optimize+ 
	/out:obj\Release\myProject.dll 
	/ruleset:"C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\Team Tools\Static Analysis Tools\\Rule Sets\MinimumRecommendedRules.ruleset" 
	/resource:obj\Release\myProject.g.resources 
	/target:library 
	/utf8output 
	/deterministic+ 
	yourFile.cs

Expected behavior

build should either fail or succeed - depending on if you have the COM object registered.

Actual behavior

C:...\Bin\Microsoft.Common.CurrentVersion.targets(2729,5): warning MSB3283: Cannot find wrapper assembly for type library "MSHTML". Verify that (1) the COM component is registered correctly and (2) your target platform is the same as the bitness of the COM component. For example, if the COM component is 32-bit, your target platform must not be 64-bit. [C:\Proj.csproj]
Done executing task "ResolveComReference" -- FAILED

The build will fail with exit code 1!
but you'll still see "0 Error(s)"

Environment data

tested on both:
msbuild /version output:

Microsoft (R) Build Engine version 16.4.0+e901037fe for .NET Framework
Copyright (C) Microsoft Corporation. All rights reserved.

16.4.0.56107

And

Microsoft (R) Build Engine version 15.9.21+g9802d43bc3 for .NET Framework
Copyright (C) Microsoft Corporation. All rights reserved.
15.9.21.664

OS info:

Windows Server 2016 1607 14393.3443

Side note:

As I suspected it's an issue with the content of the GAC, here's a list of the content:
gacutil-list.txt

[itsho]

Issue still present in VS2019 build tools:

Microsoft (R) Build Engine version 16.5.0+d4cbfca49 for .NET Framework
Copyright (C) Microsoft Corporation. All rights reserved.
16.5.0.12403

[Forgind]

Can you please explain why MSBuild assemblies are in the GAC in the first place? We do not recommend having them there for any reason.

[itsho]

I'm not sure I'm following. I didn't place any DLL in GAC. All I said as a side note is that I suspect that the issue is related to GAC.

Can you specify which DLLs are you referring to?

[Forgind]

Microsoft.Build, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL
Microsoft.Build.Conversion.v4.0, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL
Microsoft.Build.Engine, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL
Microsoft.Build.Framework, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL
Microsoft.Build.Tasks.v4.0, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL
Microsoft.Build.Utilities.v4.0, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL

Try removing those and see what happens. Having our assemblies in the GAC can cause confusing version mismatches. We aren't entirely sure how they get there so often, but we're working on removing them:
#5626

[itsho]

I'm sorry, but I didn't got approval to remove these DLLs from GAC.

To bypass the issue our IT have copied MSHTML assemblies into the GAC.

[itsho]

I've tried to compile the same project on a clean machine with VS2019 16.7.2 and got the following result:

so I suppose that the issue is fixed.