We used to pass this to all projects using (from release/8.0.1xx):

On the main branch there is now:

Is this doing something different than before, so that this change is required?

If this is for making --usemonoruntime work when not specifying --source-build, then the fix may be to not make this BuildArgs assignment conditional on "'$(DotNetBuildSourceOnly)' == 'true'".

SourceBuildUseMonoRuntime affects other repos too (aspnetcore and installer).

Urgh, not sure how I missed the Directory.Build.Props handling of this.

If this property doesn't just affect source-build then the name is misleading and should be updated.

You're right, of course, but coordinating property renames across multiple repos is horrible.

Can you please file a tracking issue so that this doesn't get lost in /dev/null?