MS Coverage output isn't cleaning compiler generated methods/types

[erichiller]

Describe the bug
When using Microsoft CodeCoverage (aka dotnet-coverage) which can now export in Cobertura format, the Cobertura is not cleaned up for compiler generated types and methods where the names are mangled.

A real example, for a single class, the following classes are present in the CodeCoverage output Cobertura file:

<class line-rate="0.7832167832167832" branch-rate="0.75" complexity="58" name="RequestState.RequestStateManager&lt;TRequestMessage, TResponseMessage, TChannelOutput&gt;" filename="RequestState/RequestStateManager.cs">
<class line-rate="1" branch-rate="1" complexity="4" name="RequestState.RequestStateManager.&lt;&lt;GetChannelForRequestAsync&gt;g__addDbStorageAsync|14_0&gt;d&lt;TRequestMessage, TResponseMessage, TChannelOutput&gt;" filename="RequestState/RequestStateManager.cs">
<class line-rate="1" branch-rate="1" complexity="2" name="RequestState.RequestStateManager.&lt;&gt;c&lt;TRequestMessage, TResponseMessage, TChannelOutput&gt;" filename="RequestState/RequestStateManager.cs">
<class line-rate="1" branch-rate="1" complexity="1" name="RequestState.RequestStateManager.&lt;&gt;c__DisplayClass19_0&lt;TRequestMessage, TResponseMessage, TChannelOutput&gt;" filename="RequestState/RequestStateManager.cs">
<class line-rate="0.6153846153846154" branch-rate="0.5" complexity="4" name="RequestState.RequestStateManager.&lt;ClearRequestStateAsync&gt;d__17&lt;TRequestMessage, TResponseMessage, TChannelOutput&gt;" filename="RequestState/RequestStateManager.cs">
<class line-rate="0.84" branch-rate="0.8" complexity="10" name="RequestState.RequestStateManager.&lt;CompleteRequestAsync&gt;d__19&lt;TRequestMessage, TResponseMessage, TChannelOutput&gt;" filename="RequestState/RequestStateManager.cs">
<class line-rate="1" branch-rate="1" complexity="1" name="RequestState.RequestStateManager.&lt;DisposeAsync&gt;d__33&lt;TRequestMessage, TResponseMessage, TChannelOutput&gt;" filename="RequestState/RequestStateManager.cs">
<class line-rate="0.8888888888888888" branch-rate="0.9166666666666666" complexity="12" name="RequestState.RequestStateManager.&lt;DisposeAsyncCore&gt;d__34&lt;TRequestMessage, TResponseMessage, TChannelOutput&gt;" filename="RequestState/RequestStateManager.cs">
<class line-rate="1" branch-rate="1" complexity="4" name="RequestState.RequestStateManager.&lt;mkmrk-DataSource-Ibkr-RequestState-IMessageStateManager-MarkSentAsync&gt;d__30&lt;TRequestMessage, TResponseMessage, TChannelOutput&gt;" filename="RequestState/RequestStateManager.cs">

Which results in the following classes being reported:

Name	Line	Branch	Method
RequestState.RequestStateManager.<>c<TRequestMessage, TResponseMessage, TChannelOutput>	100%
RequestState.RequestStateManager<TRequestMessage, TRe sponseMessage, TChannelOutput>	77.3%	75%	85.7%
RequestState.RequestStateManager<TRequestMessage, TRe sponseMessage, TChannelOutput>	87.3%	85.2%	100%
RequestState.RequestStateManager<TRequestMessage, TRe sponseMessage>	65.3%	66.6%	100%

To Reproduce
Any use of Microsoft CodeCoverage on any codebase with constructs such as async methods, local functions, etc. causes these same issues.

[danielpalme]

Probably Microsoft CodeCoverage uses a slightly different formatting that other tools (e.g. coverlet).
I will look into this within the next days and try to handle this format as well.

[danielpalme]

My assumption is correct. The format is different:

dotnet-test
Test.ClassWithLocalFunctions.MyNestedClass<T1, T2>
Test.ClassWithLocalFunctions.MyNestedClass.<MyAsyncMethod>d__4<T1, T2, T3>
Test.ClassWithLocalFunctions.MyNestedClass.<>c__DisplayClass4_0.<<MyAsyncMethod>g__MyAsyncLocalFunction|0>d<T1, T2, T3, T4>

coverlet
Test.ClassWithLocalFunctions1/MyNestedClass1
Test.ClassWithLocalFunctions1/MyNestedClass1/<MyAsyncMethod>d__41 Test.ClassWithLocalFunctions1/MyNestedClass1/<>c__DisplayClass4_01/<<MyAsyncMethod>g__MyAsyncLocalFunction|0>d`1

Will have to adjust in ReportGenerator

[danielpalme]

I invested several hours, but I have not yet found a way filter out those classes and at the same time don't miss any relevant coverage results.