snapcraft isn't context aware in displaying help text

[Dilyn]

When using snapcraft 7.x and attempting to build a core20 base snap, the options available from snapcraft --help are in general not available when building the snap. For example, --verbosity is not a valid option when using snapcraft 7 to build a core20 base snap:

dilyn@Ares:~work/test -> snapcraft --verbosity=verbose
Starting Snapcraft 7.1.4.post49+git3a54031c
Logging execution to '/root/.cache/snapcraft/log/snapcraft-20220922-112604.562413.log'
Usage: snapcraft [OPTIONS] COMMAND [ARGS]...
Try 'snapcraft -h' for help.

Error: No such option: --verbosity Did you mean --version?

I would expect that snapcraft --help would display context-aware options -- based on the base declared in the snapcraft.yaml for the snap I am building, it should display the flags which will govern its behavior in building said snap.

[Dilyn (dilyn-corner)]

Reconfirming that this issue is still present in both latest/stable (rev. 8931) and latest/edge (rev 9020):

dilyn@Ares:~/test -> snapcraft --verbosity=verbose
Starting Snapcraft 7.3.1.post31+git0b95d4c7
Logging execution to '/home/dilyn/.local/state/snapcraft/log/snapcraft-20230327-115030.405829.log'
Usage: snapcraft [OPTIONS] COMMAND [ARGS]...
Try 'snapcraft -h' for help.

Error: No such option: --verbosity (Possible options: --verbose, --version)