Documentation should say about libxml2 is required for code coverage

[CAPCHIK]

Hi!

After upgrading from 1.17.36 to 1.18.0 code coverage percents grows to 100%.

In real that's not a good work, but silent error in TUnit coverage works. In version 1.17.36 coverage works OK in dotnet sdk container without libxml2.

But after updating to 1.18.0 code coverage always generated as

<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<coverage line-rate="1" branch-rate="1" complexity="1" version="1.9" timestamp="1772520830">
  <packages />
</coverage>

I found reason of that behavior after try to use dotnet-coverage collect 'dotnet run' instead of dotnet run --coverage. dotnet-coverage prints next message:

No code coverage data available. Profiler was not initialized. Verify that glibc (>=2.27), libxml2 and all .NET dependencies are installed.

I don't know, where information of libxml2 should be placed, but now GitLab CI example will not collect code coverage on clean base image mcr.microsoft.com/dotnet/sdk:9.0

[CAPCHIK]

Example of described behavior here - https://github.com/CAPCHIK/TUnitBugExample/actions/runs/22611857290/job/65515816774

Workflow runs on mcr.microsoft.com/dotnet/sdk:9.0.311, collect coverage successfully on 1.17.16. On version 1.18.0 can collect only after installing libxml2

[thomhurst]

Sorry @CAPCHIK I forgot to reply. I believe this is fixed in the latest version of the code coverage library?

[CAPCHIK]

Yes! 1.19.57 resolves the coverage issue when libxml2 is not present. 🎉

Could you explain why libxml2 was required before and is not anymore? I'm trying to understand the logic behind the change.

[thomhurst]

Can't tell you honestly - the code coverage library is made by Microsoft. TUnit just brings it in as a transitive package reference