[BUG] Includes reports for temporary (?) build files in coverage.cobertura.xml

[ruffin-bailey-fhr]

Describe the bug

When running dotnet test with "XPlat Code Coverage" one project is including temporary (or non-existent?), assumedly build-related files in the cobertura report.

When a coverage report is created (fully aware this is another tool; this is simply how I found the issue), many lines of errors like this are reported:

2025-07-25T16:10:02: File 'C:\build\_work\138\s\src\ACME.Common\Code\Attributes\AuditField.cs' does not exist (any more).

Note that ACME.Common is an in-project reference for the project being tested.

To Reproduce

Going to be hard to reproduce exactly without access to our project, but here's how I reproduce locally.

Run from the home folder of the test project's csproj file (C:\OurAppPath\ACME.OurSolution\tests\ACME.Diagnostics.Tests):

dotnet test --settings:..\tests.runsettings `
        --collect:"XPlat Code Coverage" `
        -- RunConfiguration.DisableAppDomain=true

tests.runsettings content (located in parent tests folder):

<?xml version="1.0" encoding="utf-8" ?>
<RunSettings>
 <DataCollectionRunSettings>
     <DataCollectors>
         <DataCollector friendlyName="XPlat code coverage">
             <Configuration>
                 <Format>cobertura,opencover</Format>
                 <Exclude>**build**</Exclude>
             </Configuration>
         </DataCollector>
     </DataCollectors>
 </DataCollectionRunSettings>
</RunSettings>

Expected behavior

Reports only on the files in the solution.

Actual behavior

Returns results from temporary or non-existant files outside of the solution.

<?xml version="1.0" encoding="utf-8"?>
<coverage line-rate="0.4432" branch-rate="0.3178" version="1.9" timestamp="1753468984" lines-covered="535" lines-valid="1207" branches-covered="191" branches-valid="601">
    <sources>
        <source>C:\</source>
    </sources>
    <packages>
        <package name="ACME.Common" line-rate="0.1638" branch-rate="0.1173" complexity="597">
            <classes>
                <class name="System.StringHelper" filename="build\_work\138\s\src\ACME.Common\Code\StringHelper.cs" line-rate="0" branch-rate="0" complexity="22">

<!-- and it continues. That's the first one -->

Again, note that ACME.Common is an in-project reference for the project being tested.

Configuration (please complete the following information):

Please provide more information on your .NET configuration:

• Which coverlet package and version was used?
  • coverlet --version
    • 6.0.4.1+90b21079d4
• Which version of .NET is the code running on?
  • Testing project: .NET Framework 4.7
  • Project under test: .NET Framework 4.0
• What OS and version, and what distro if applicable?
  • Edition Windows 11 Enterprise
  • Version 23H2
  • OS build 22631.5472
  • Experience Windows Feature Experience Pack 1000.22700.1106.0
• What is the architecture (x64, x86, ARM, ARM64)?
  • x64
• Do you know whether it is specific to that configuration?
  • Which configuration? Windows 11 (& associated stack) or this project's configuration?
    • If the latter, it does not add these files to another set of tests, though those test & tested projects does not reference ACME.Common, a Project reference.
    • If the former, I am unable to test on another operating system.

Additional context

[X] ❗ Please also read Known Issues