Coverlet fails on concurrent runs

[tkukushkin]

Hello!

We write functional tests on python and want to collect coverage from our dotnet applications. Tests start several instances of same dll with different parameters. We used dotcover before and everything was fine. But with coverlet we get such error:

---> System.IO.IOException: The process cannot access the file '/Users/tkukushkin/Projects/builders-balance/Scheduler/bin/Debug/netcoreapp3.1/Scheduler.pdb' because it is being used by another process.
   at System.IO.FileStream.Init(FileMode mode, FileShare share, String originalPath)
   at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options)
   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 /_/src/coverlet.core/Helpers/FileSystem.cs:line 33
   at Coverlet.Core.Helpers.InstrumentationHelper.<>c__DisplayClass12_0.<RestoreOriginalModules>b__0() in /_/src/coverlet.core/Helpers/InstrumentationHelper.cs:line 245
   at Coverlet.Core.Helpers.RetryHelper.<>c__DisplayClass0_0.<Retry>b__0() in /_/src/coverlet.core/Helpers/RetryHelper.cs:line 26
   at Coverlet.Core.Helpers.RetryHelper.Do[T](Func`1 action, Func`1 backoffStrategy, Int32 maxAttemptCount) in /_/src/coverlet.core/Helpers/RetryHelper.cs:line 52
   --- End of inner exception stack trace ---
   at Coverlet.Core.Helpers.RetryHelper.Do[T](Func`1 action, Func`1 backoffStrategy, Int32 maxAttemptCount) in /_/src/coverlet.core/Helpers/RetryHelper.cs:line 59
   at Coverlet.Core.Helpers.RetryHelper.Retry(Action action, Func`1 backoffStrategy, Int32 maxAttemptCount) in /_/src/coverlet.core/Helpers/RetryHelper.cs:line 28
   at Coverlet.Core.Helpers.InstrumentationHelper.RestoreOriginalModules() in /_/src/coverlet.core/Helpers/InstrumentationHelper.cs:line 242
   at Coverlet.Core.Helpers.InstrumentationHelper.<.ctor>b__5_0(Object s, EventArgs e) in /_/src/coverlet.core/Helpers/InstrumentationHelper.cs:line 26
   at System.AppContext.OnProcessExit()
 ---> (Inner Exception #1) System.IO.IOException: The process cannot access the file '/Users/tkukushkin/Projects/builders-balance/Scheduler/bin/Debug/netcoreapp3.1/Scheduler.pdb' because it is being used by another process.
   at System.IO.FileStream.Init(FileMode mode, FileShare share, String originalPath)
   at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options)
   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 /_/src/coverlet.core/Helpers/FileSystem.cs:line 33
   at Coverlet.Core.Helpers.InstrumentationHelper.<>c__DisplayClass12_0.<RestoreOriginalModules>b__0() in /_/src/coverlet.core/Helpers/InstrumentationHelper.cs:line 245
   at Coverlet.Core.Helpers.RetryHelper.<>c__DisplayClass0_0.<Retry>b__0() in /_/src/coverlet.core/Helpers/RetryHelper.cs:line 26
   at Coverlet.Core.Helpers.RetryHelper.Do[T](Func`1 action, Func`1 backoffStrategy, Int32 maxAttemptCount) in /_/src/coverlet.core/Helpers/RetryHelper.cs:line 52<---

coverlet.console version: 1.7.0.0

[MarcoRossignoli]

Can you explain how you use coverlet command?Run parallel(on same test file) coverlet xxx won't work because file is instrumented and restored at every test run so you'll get concurrent access to same dll during instrumentation.

[tkukushkin]

Dll is always the same.

coverlet <some-dll> --target dotnet --targetargs "exec <some-dll>" --include-test-assembly <other-options>

Maybe there is some workaround for our case?

[MarcoRossignoli]

mmm at the moment no...you need to run tasks in a sequential way. Or use some other way like collectors and run all different test project in parallel, are you running on .NET Framework or .NET Core?

We used dotcover before and everything was fine

I don't know ho dotcover works, just for curiosity can you attach dotcover run script?

[tkukushkin]

We run .NET Core, but our dll is not test suite, we run real application under coverage, tests written on Python, one test can use several instances of application (for example one instance can be web, second instance can be rabbitmq consumer). After all we merge reports from all application runs in single report.

Our dotcover command:

dotcover.sh  dotnet --ReportType=DetailedXML --Output=detailed.xml <other options> -- exec <some-dll>

[MarcoRossignoli]

You could try something like that #781 (comment)
But with different copy of artifacts

[tkukushkin]

What do you mean by "different copy of artifacts"?

[MarcoRossignoli]

Build one time...move artifacts in different folders fold1/fold2/fold3 and run in parallel coverlet fold1... coverlet fold2... etc... to avoid concurrent file access on instrumentation.

[tkukushkin]

OK, I understand, thanks!