Directory.Build.props

<Project>

    <!--
      What every project in the repository gets, so that the build is the same wherever it is
      run: from the command line, from Rider, or on the CI runner.
    -->

    <PropertyGroup>

        <!--
          A warning is an error. The build is warning-clean and stays that way: a rule measured
          against Word is worth nothing if the code that carries it is drifting quietly, and the
          compiler's warnings are the cheapest reading of that drift there is.

          This was on the CI command line alone (`dotnet build -warnaserror`), which meant a
          warning could live in the tree for as long as it took someone to push. Here it is caught
          by the build that introduces it. The workflows still pass the flag, which now says the
          same thing twice on purpose: a project that somehow escaped this file would still be
          held to it there.

          To build past one while working, and only while working:

              dotnet build -p:TreatWarningsAsErrors=false
        -->
        <TreatWarningsAsErrors>true</TreatWarningsAsErrors>

        <!--
          Except NuGet's own audit, which reports what is known about a package today rather than
          anything about this code. An advisory against the test runner is worth seeing and is not
          worth a build that cannot be made to pass — the shipping library has no packages at all
          to be advised about, and a build of an old commit would fail for something published
          after it was written.
        -->
        <WarningsNotAsErrors>$(WarningsNotAsErrors);NU1900;NU1901;NU1902;NU1903;NU1904</WarningsNotAsErrors>

    </PropertyGroup>

</Project>