confusing syntax for vis-subtract, "no sources specified for subtraction"

[d3v-null]

without --invert , vis-subtract will throw an error No sources were specified for subtraction for a perfectly valid seeming command like

hyperdrive vis-subtract -n ${num_sources} ...

Relevant help message

SKY-MODEL SOURCES:
    -i, --invert                                          Invert the subtraction; sources *not* specified in sources-to-subtract will be subtracted from the input data
        --sources-to-subtract <SOURCES_TO_SUBTRACT>...    The names of the sources in the sky-model source list that will be subtracted from the input data

potential solutions:

• invert by default if no --sources-to-subtract
• deprecate --invert and add --sources-to-skip

[JLBLine]

Thanks @d3v-null . Probably easiest is to invert default with no sources-to-subtract just for backwards compatibility. The biggest confusion is probably this help message

-n, --num-sources <NUM_SOURCES>   The number of sources to use in the source list. The default is to use them all. Example: If 1000 sources are specified here, then the top 1000 sources are used (based on their flux densities after the beam attenuation) within the specified source distance cutoff

That reads like you don't need the --invert option at all.