config: Improve input checking in config command

[jerry-skydio]

Previously you could use config to set an invalid value, which would
prevent you from ever running config again to fix it.

• Run config before loading the parsed config into args. This ensures
  that invalid config files won't prevent running config, and config itself can't
  be configured anyway.

• Add a --delete option to config to delete keys

• Validate that the given config command and option are actually valid. if invalid,
  suggest a list of valid options.

• Error out if the provided value is invalid for the given option, and also add
  choices to the validity check.

Topic: improveconfig
Reviewers: aaron, brian-k

[jerry-skydio]

Reviews in this chain:
└#209 config: Improve input checking in config command

[jerry-skydio]

#	head	base	diff	date	summary
0	2c402d32	159f964c	diff	Dec 30 17:46 PM	3 files changed, 107 insertions(+), 75 deletions(-)
1	eea3ccd2	159f964c	diff	Dec 30 20:05 PM	2 files changed, 47 insertions(+), 28 deletions(-)
2	cce56da6	159f964c	diff	Dec 30 20:12 PM	1 file changed, 6 insertions(+), 2 deletions(-)
3	59bcdde4	159f964c	diff	Dec 30 20:28 PM	2 files changed, 19 insertions(+), 5 deletions(-)
4	1bb71de9	159f964c	diff	Dec 30 20:30 PM	1 file changed, 1 insertion(+), 1 deletion(-)

[aaron-skydio]

Very nice

[aaron-skydio]

Is this idiomatic? I tend to think short cli args can be stacked like tool -abcdef, and yeah that's how argparse works also: https://docs.python.org/3/library/argparse.html#option-value-syntax

It seems like it'd be confusing to pass e.g. -nx and not know if that's short for -n -x or --no-xlong-argument, I think the way revup is set up here it'd always be --no-xlong-argument but I'm not sure if I've seen a cli tool where that'd be the case

[jerry-skydio]

yeah true, fwiw we don't have any flags that use -n for roughly this reason (except stragglers in toolkit that can be changed) would this be better if we formalized that?

we can also get rid of the short syntax and use only --no- longform syntax, i'm not that attached to it

[aaron-skydio]

I think I'd rather use only --no- longform

[jerry-skydio]

sg i'll make that a new pr though, its not strictly related to this

[aaron-skydio]

SGTM