Build agent (azure devops) builds fine but local build fails

Question

I have a build pipeline in AzureDevOps that builds a .NET Core 5 solution using the AzureDevOps Task '.NET Core' -> Build

The solution has a Directory.Build.props file that has the setting:

<PropertyGroup>
    <TreatWarningsAsErrors>True</TreatWarningsAsErrors>
</PropertyGroup>

That means that any warning will be propagated as error.

After some time a collegae encountered a local build fail (it is a warning CS8603: Possible null reference return -> which become an error due to our setting) but the build pipeline succeeds with the same code base (commit).

The build agent has the following .NET Core SDK versions: 5.0.402, 5.0.408.

The local dev machine uses VS2022 with .NET Core SDK versions: 2.1.300, 2.1.402, 2.1.526, 2.1.700, 3.1.420, 5.0.401, 5.0.408 and 6.0.301

Outside VS2022, a local dotnet build has the same error.

What could be the issue here ?

Answer 1

Well... somehow I didn't notice the warning was indeed remote, but it was not a CSC compiler warning, but a Sonar warning.

When using the MSBuildTreatWarningsAsErrors like this:

  <PropertyGroup>
    <TreatWarningsAsErrors>True</TreatWarningsAsErrors>
    <MSBuildTreatWarningsAsErrors>true</MSBuildTreatWarningsAsErrors>
  </PropertyGroup>

we see the Sonar warnings as errors also in Azure DevOps.

(solution based on this SO topic: Azure Devops dotnet build don't respect configuration)