Something about using const enum from aspnetcore included reference causes no coverage to be generated for the whole project

[Cyberboss]

Very minimal repro in this repro.

Essentially it boils down to this default assignment in an aspnetcore project

#if SHOW_REPRO
		const LogLevel DefaultLogLevel = LogLevel.Debug;
		LogLevel LogLevel { get; set; } = DefaultLogLevel;
#else
		LogLevel LogLevel { get; set; } = LogLevel.Debug;
#endif

Above case fails, below case doesn't.

I'm going to paste the README.md from that repo here:

Coverlet Bug Demo

This is reproducible on net 6, 7, and 8 preview 6.

A more "in the wild" repro can be found in https://github.com/tgstation/tgstation-server/tree/fc007543dbfa888cd274e5a54a512e830641fd1b by running the tests/Tgstation.Server.Host.Tests project.

No Coverage

For guaranteed clean execution, execute with:

Powershell:

Remove-Item -Recurse -Force Library/bin, Library/obj, Test/bin, Test/obj;dotnet restore;dotnet test -c Debug --collect:"XPlat Code Coverage" --settings test.runsettings --results-directory TestResults

or Bash:

rm -rf Library/bin, Library/obj, Test/bin, Test/obj && dotnet restore; dotnet test -c Debug --collect:"XPlat Code Coverage" --settings test.runsettings --results-directory TestResults

No coverage output will be generated in the cobertura.xml

Broken Coverage

In Common.props change PdbType to PdbOnly or Full. Running the above command again will yield an error as warning repeated many times:

 ---> (Inner Exception #11) System.IO.IOException: The process cannot access the file 'S:\workspace\net8-coverlet-error\Test\bin\Debug\net8.0\Library.pdb' because it is being used by another process.
   at System.IO.FileSystem.CopyFile(String sourceFullPath, String destFullPath, Boolean overwrite)
   at Coverlet.Core.Helpers.FileSystem.Copy(String sourceFileName, String destFileName, Boolean overwrite) in /_/src/coverlet.core/Helpers/FileSystem.cs:line 35
   at Coverlet.Core.Helpers.InstrumentationHelper.<>c__DisplayClass16_0.<RestoreOriginalModule>b__1() in /_/src/coverlet.core/Helpers/InstrumentationHelper.cs:line 277
   at Coverlet.Core.Helpers.RetryHelper.<>c__DisplayClass0_0.<Retry>b__0() in /_/src/coverlet.core/Helpers/RetryHelper.cs:line 28
   at Coverlet.Core.Helpers.RetryHelper.Do[T](Func`1 action, Func`1 backoffStrategy, Int32 maxAttemptCount) in /_/src/coverlet.core/Helpers/RetryHelper.cs:line 55<---

   --- End of inner exception stack trace ---
   at Coverlet.Collector.DataCollection.CoverageManager.InstrumentModules() in /_/src/coverlet.collector/DataCollection/CoverageManager.cs:line 72
   at Coverlet.Collector.DataCollection.CoverletCoverageCollector.OnSessionStart(Object sender, SessionStartEventArgs sessionStartEventArgs) in /_/src/coverlet.collector/DataCollection/CoverletCoverageCollector.cs:line 143.

Workaround 1

In Common.props set ShowRepro to false. The only thing this does is inline the usage of the const Microsoft.Extensions.Logging.LogLevel enum.

Workaround 2

In Common.props set ShowRepro to true and AddExplicitProjectReference to true. The only thing this does is explicitly add the Microsoft.Extensions.Logging.Abstractions package which is included by default in the AspNetCore SDK.

[Cyberboss]

This is a very annoying bug because, while I've identified this single case, there are other cases in my very large project which are going to be painful to track down.

For some reason, in my larger project, adding the PackageReference is not a workaround and I had to remove the consts.

[daveMueller]

I think this was fixed in #1449 and will then be in the next release. Unfortunately our nighly builds are currently not running (#1511) and the only way for you to consume it would be to compile coverlet on your own.
If I do this locally I'll get a non-empty report.

Besides compiling the current master branch, I had to add <PreserveCompilationContext>true</PreserveCompilationContext> to the tests' project file.

[daveMueller]

OK so nightly build is running again and you can now consume the packages as described here https://github.com/coverlet-coverage/coverlet#consume-nightly-build. I also tested your sample again with the build from tonight. Just add <PreserveCompilationContext>true</PreserveCompilationContext> and coverage will be calculated.