How to have a build settings defined in "base", while customising it further in "config/Release"?

Hi 👋

I have the following spec:

...
settings:
  base:
    OTHER_SWIFT_FLAGS:
      - -Xfrontend
      - -warn-long-expression-type-checking=500
      - -Xfrontend
      - -warn-long-function-bodies=1000

  configs:
    Release:
      OTHER_SWIFT_FLAGS:
        - -Xfrontend 
        - -internalize-at-link
...

The intended behaviour is that:

• For all configurations, OTHER_SWIFT_FLAGS has a value of -Xfrontend -warn-long-expression-type-checking=500 -Xfrontend -warn-long-function-bodies=1000
• For release configuration, OTHER_SWIFT_FLAGS has a value of -Xfrontend -warn-long-expression-type-checking=500 -Xfrontend -warn-long-function-bodies=1000 -Xfrontend -internalize-at-link

The reality (which is somewhat expected) is that:

• For all configurations, OTHER_SWIFT_FLAGS has a value of -Xfrontend -warn-long-expression-type-checking=500 -Xfrontend -warn-long-function-bodies=1000
• For release configuration, OTHER_SWIFT_FLAGS has a value of -Xfrontend -internalize-at-link

Is there any way to achieve the intended behaviour?

Thanks! 🙏

The issue provides no repository file or test path. Start by tracing how the YAML settings.base and configs.Release values are parsed and merged, then verify the behavior with a minimal spec; done means Release retains base OTHER_SWIFT_FLAGS and appends its own flags while other configurations remain unchanged.