Incremental builds are broken when using the Microsoft.NET.Test.Sdk package

[ViktorHofer]

Description

When building a test project which references the Microsoft.NET.Test.Sdk nuget package, incremental builds are broken because of double writes:

Steps to reproduce

dotnet new xunit -n xunittest
cd xunittest
dotnet build
dotnet build /bl

Expected behavior

There shouldn't be any double writes observable in the msbuild binary log file (which can be opened with the msbuild log viewer).

Actual behavior

The msbuild binary log viewer shows double writes (see picture above) which causes incremental builds to be broken which means that the affected test library needs to always be fully rebuilt. This is especially noticeable for customers when having many test assemblies which are built (i.e. via a sln file).

Diagnostic logs

Not required as this is about building and not running any tests so the test adapter isn't even invoked.

Environment

Windows, SDK version 6.0.200-preview.21617.4.

cc @nohwnd

[nohwnd]

@drognanar this seems like something that would be right up your alley. Would you mind having a look?

[ktaeleman]

I'm noticing the same issue with 16.11.0. The double copy seems to stem from:

• Microsoft.TestPlatform.TestHost's build folder being added to the Content ItemGroup of the test projects
• The ResolvePackageAssets task adding the lib folder of Microsoft.TestPlatform.ObjectModel due to dependency on Microsoft.NET.Test.Sdk

which both contain Microsoft.TestPlatform.PlatformAbstractions.dll.

[shueybubbles]

I'm running into this now. Does anyone have a good workaround?
BTW it's not just incremental builds, it's happening on clean multi-targeting builds.
I can share a binlog internally. @nohwnd

[nohwnd]

@shueybubbles We internally assigned this to @drognanar. Artur do you have some update please? The description here seems to be enough to repro find a potential fix.

[KirillOsenkov]

Ran into this as well while investigating why our incremental build was broken.

Encountered conflict between 'CopyLocal:/Users/kirill/.nuget/packages/microsoft.testplatform.objectmodel/17.1.0/lib/netcoreapp2.1/Microsoft.TestPlatform.PlatformAbstractions.dll' and 'CopyLocal:/Users/kirill/.nuget/packages/microsoft.testplatform.testhost/17.1.0/lib/netcoreapp2.1/Microsoft.TestPlatform.PlatformAbstractions.dll'.
Choosing 'CopyLocal:/Users/kirill/.nuget/packages/microsoft.testplatform.objectmodel/17.1.0/lib/netcoreapp2.1/Microsoft.TestPlatform.PlatformAbstractions.dll' arbitrarily as both items are copy-local and have equal file and assembly versions.

This is because both Microsoft.TestPlatform.ObjectModel and Microsoft.TestPlatform.TestHost NuGet packages include Microsoft.TestPlatform.PlatformAbstractions.dll.

The shared .dll(s) need to go into their own package(s) and a dependency needs to be added from all packages that depend on it.

[shueybubbles]

FWIW My workaround is to greatly increase the size of my build by putting the output of every test project in its own subfolder. We run the tests as part of the build, so this double write was blocking test runs due to the file copy being blocked by currently running tests.

<OutputPath>$(OutputPath)\$(MSBuildProjectName)</OutputPath>

[Evangelink]

Ping @drognanar

[drognanar]

Closing via #3722