"The process cannot access the file, because it is being used by another process" error during attempt to collect coverage

The error message for MSBuild intergration

C:\Users\xxx\.nuget\packages\coverlet.msbuild\2.8.1\build\coverlet.msbuild.targets(36,5): error : One or more errors occurred. (The process cannot access the file 'D:\Work\xxx\yyy\test\yyy.Tests\bin\Debug\netcoreapp2.1\zzz.Dto.dll' because it is being used by another process.)[D:\Work\xxx\yyy\test\yyy.Tests\yyy.Tests.csproj]
C:\Users\xxx\.nuget\packages\coverlet.msbuild\2.8.1\build\coverlet.msbuild.targets(36,5): error :    at Coverlet.Core.Helpers.RetryHelper.Do[T](Func`1 action, Func`1 backoffStrategy, Int32 maxAttemptCount) in c:\git\coverletToRelease\src\coverlet.core\Helpers\RetryHelper.cs:line 59 [D:\Work\xxx\yyy\test\yyy.Tests\yyy.Tests.csproj]
C:\Users\xxx\.nuget\packages\coverlet.msbuild\2.8.1\build\coverlet.msbuild.targets(36,5): error :    at Coverlet.Core.Helpers.RetryHelper.Retry(Action action, Func`1 backoffStrategy, Int32 maxAttemptCount) in c:\git\coverletToRelease\src\coverlet.core\Helpers\RetryHelper.cs:line 28 [D:\Work\xxx\yyy\test\yyy.Tests\yyy.Tests.csproj]
C:\Users\xxx\.nuget\packages\coverlet.msbuild\2.8.1\build\coverlet.msbuild.targets(36,5): error :    at Coverlet.Core.Helpers.InstrumentationHelper.RestoreOriginalModule(String module, String identifier) in c:\git\coverletToRelease\src\coverlet.core\Helpers\InstrumentationHelper.cs:line 219 [D:\Work\xxx\yyy\test\yyy.Tests\yyy.Tests.csproj]
C:\Users\xxx\.nuget\packages\coverlet.msbuild\2.8.1\build\coverlet.msbuild.targets(36,5): error :    at Coverlet.Core.Coverage.GetCoverageResult() in c:\git\coverletToRelease\src\coverlet.core\Coverage.cs:line 219 [D:\Work\xxx\yyy\test\yyy.Tests\yyy.Tests.csproj]
C:\Users\xxx\.nuget\packages\coverlet.msbuild\2.8.1\build\coverlet.msbuild.targets(36,5): error :    at Coverlet.MSbuild.Tasks.CoverageResultTask.Execute() in c:\git\coverletToRelease\src\coverlet.msbuild.tasks\CoverageResultTask.cs:line 113 [D:\Work\xxx\yyy\test\yyy.Tests\yyy.Tests.csproj]

The same behavior for VSTest integration

---> (Inner Exception #1) System.IO.IOException: The process cannot access the file 'D:\Work\xxx\yyy\test\yyy.Tests\bin\Debug\netcoreapp2.1\zzz.dll' because it is being used by another process.
   at System.IO.FileSystem.CopyFile(String sourceFullPath, String destFullPath, Boolean overwrite)
   at System.IO.File.Copy(String sourceFileName, String destFileName, Boolean overwrite)
   at Coverlet.Core.Helpers.FileSystem.Copy(String sourceFileName, String destFileName, Boolean overwrite) in c:\git\coverletToRelease\src\coverlet.core\Helpers\FileSystem.cs:line 33
   at Coverlet.Core.Helpers.InstrumentationHelper.<>c__DisplayClass10_0.<RestoreOriginalModule>b__0() in c:\git\coverletToRelease\src\coverlet.core\Helpers\InstrumentationHelper.cs:line 215
   at Coverlet.Core.Helpers.RetryHelper.<>c__DisplayClass0_0.<Retry>b__0() in c:\git\coverletToRelease\src\coverlet.core\Helpers\RetryHelper.cs:line 26
   at Coverlet.Core.Helpers.RetryHelper.Do[T](Func`1 action, Func`1 backoffStrategy, Int32 maxAttemptCount) in c:\git\coverletToRelease\src\coverlet.core\Helpers\RetryHelper.cs:line 52<---

It happens all the time, when I try to collect coverage for xunit test projects (with NUnit everything works fine suddenly) using default commands, like dotnet test --collect:"XPlat Code Coverage" or dotnet test /p:CollectCoverage=true

Adding -nr:false -m:1 arguments to MSBuild didn’t help, as well as running commands with separate csproj file. I’ve used the latest versions of coverlet, xunit and Microsoft.NET.Test.Sdk packages

<PackageReference Include="coverlet.collector" Version="1.2.1">
  <PrivateAssets>all</PrivateAssets>
  <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
</PackageReference>
<PackageReference Include="coverlet.msbuild" Version="2.8.1">
  <PrivateAssets>all</PrivateAssets>
  <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
</PackageReference>
<PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.6.1" />
<PackageReference Include="Moq" Version="4.14.1" />
<PackageReference Include="xunit" Version="2.4.1" />
<PackageReference Include="xunit.runner.visualstudio" Version="2.4.1">
  <PrivateAssets>all</PrivateAssets>
  <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
</PackageReference>

Installed SDKs are below

.NET Core SDK (reflecting any global.json):
 Version:   3.1.202
 Commit:    6ea70c8dca

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.18363
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\3.1.202\

Host (useful for support):
  Version: 3.1.4
  Commit:  0c2e69caa6

.NET Core SDKs installed:
  2.1.806 [C:\Program Files\dotnet\sdk]
  3.1.202 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.18 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.8 [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 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.4 [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 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Migrated from comments of 725 issue

[MarcoRossignoli]

Uploaded coverlet.msbuild.2.9.1-preview.6.g1f7fe02d13 same feeds.

BTW my advice is to use collectors because has got better integration and doesn’t suffer of some issues https://github.com/coverlet-coverage/coverlet/blob/master/Documentation/KnownIssues.md#1-vstest-stops-process-execution-earlydotnet-test

Please let me know if works as expected!

[MarcoRossignoli]

@AntiPasha I’m working on a workaround/solution, can you try with this package(collectors driver dotnet test --collect:"XPlat Code Coverage")

nuget feed source https://f.feedz.io/marcorossignoli/coverletunofficial/nuget/index.json package version 1.3.1-preview.6.g1f7fe02d13

This is the feed I use for preview/investigation.

Branch https://github.com/coverlet-coverage/coverlet/compare/master...MarcoRossignoli:issue857