osc whatdependson for all flavors at once

[jengelh]

Is your feature request related to a problem? Please describe.

Factory maintainers use osc whatdependson openSUSE:Factory/xyz standard x86_64 to determine if a package may be deleted. This does not take into account that there may be multibuild flavors involved with their own set of dependants, and currently that requires first obtaining the list of flavors, then running whatdependson for each flavor.

$ osc whatdependson openSUSE:Factory/ffmpeg-6 standard x86_64
ffmpeg-6 :
$ osc r openSUSE:Factory/ffmpeg-6 -r standard -a x86_64
standard             x86_64     ffmpeg-6                       succeeded*
standard             x86_64     ffmpeg-6:ffmpeg-6-mini         succeeded*
$ osc whatdependson openSUSE:Factory/ffmpeg-6:ffmpeg-6-mini standard x86_64
ffmpeg-6:ffmpeg-6-mini :
      deepin-music-player
      deepin-screen-recorder
      dvbcut

Describe the solution you'd like

Implement a osc wda (osc whatdependson --all-flavors) subcommand/alias that automatically fetches the flavor list (leeching off osc r might be an idea if nothing else provides that list), and iteratively run whatdependson for each of them.

$ osc wda openSUSE:Factory/ffmpeg-6 standard x86_64
ffmpeg-6 :
ffmpeg-6:ffmpeg-6-mini :
      deepin-music-player
      deepin-screen-recorder
      dvbcut

Describe alternatives you've considered

could not think of any yet

Additional context

(Similiar proposition was made for osc build: #1718 ; I agree with the assessment that building all flavors might impose an ordering, but such ordering would not be a problem for Whatdependson/Wda)