Incorrect and insufficient documentation of `cli-compile-args` input data format

[arduino]

Incorrect and insufficient documentation of `cli-compile-args` input data format

[per1234]

Hi @Jackbennett. I see there is an error in the documentation for the cli-compile-flags input. Instead of "YAML-format list of flags", it should say "YAML-format list of arguments".

You must use a separate element in the array for each of the arguments. Your current workflow produces an Arduino CLI command like this:

arduino-cli compile "--build-property build.extra_flags=-VARIANT_SELECTED=0" [...]

If you change it to this it should work as expected (though you probably meant to use -DVARIANT_SELECTED instead of -VARIANT_SELECTED):

          cli-compile-flags: |
            - --build-property
            - build.extra_flags=-VARIANT_SELECTED=${{ matrix.variant }}

The error in the documentation should be fixed and a simple example added to demonstrate the usage.

[Jackbennett]

Mmm ok makes sense. Can confirm that's working.

          cli-compile-flags: |
            - --build-property
            - build.extra_flags=-DVARIANT_SELECTED=${{ matrix.variant }}]

And yes thanks for the -D tip I'd missed that entirely, otherwise:

 avr-g++: error: unrecognized command line option '-VARIANT_SELECTED=1'

Edit* oh and the matrix injection works as expected.