Correct Trimming RootMode for ConfigurationManager

[Trimatix]

Hi there, this is a followup after #101423.

I've rooted ConfigurationManager as described using TrimmerRootAssembly, but dotnet publish says that ConfigurationManager does not specify a RootMode, so I've given <TrimmerRootAssembly Include="System.Configuration.ConfigurationManager" RootMode="Library" />.

In this mode, I still get the Unhandled exception. System.Configuration.ConfigurationErrorsException: Configuration system failed to initialize error from #101423.

Please could you advise the correct rootmode to use for this package? I haven't been able to find the documentation for RootMode online as of yet.

Many thanks in advance

(dotnet 8, linux-x64)

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[jkotas]

System.Configuration.ConfigurationManager design is incompatible with trimming. It is not possible to make it work well in trimmed applications.

You may want to consider switching to a configuration library that is compatible with trimming such as https://learn.microsoft.com/en-us/dotnet/core/whats-new/dotnet-8/runtime#configuration-binding-source-generator . (This is documented at https://learn.microsoft.com/en-us/dotnet/core/deploying/trimming/incompatibilities#reflection-based-serializers .)

[steveharter]

System.Configuration.ConfigurationManager design is incompatible with trimming. It is not possible to make it work well in trimmed applications.

Closing;

There is some work in v10 on this: https://github.com/dotnet/runtime/pull/108464

[sbomer]

Just FYI, the work in https://github.com/dotnet/runtime/pull/108464 is designed to provide better trim warnings when using ConfigurationManager - not to make it compatible with trimming.

[Trimatix]

understood, thanks all 👍