cmd/update-reset: improve arg parsing

[carlocab]

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Currently, doing brew update-reset homebrew/core does nothing (not
even return an error). If you want to update-reset a given tap, you
must do (the equivalent of)

brew update-reset "$(brew --repository owner/tap_name)"

This isn't very intuitive, so let's do a bit more work in argument
parsing so that the user can just pass a tap name instead of a path to a
tap.

Passing a path to a tap is also still supported.

[BrewTestBot]

Review period will end on 2023-02-17 at 16:02:18 UTC.

[MikeMcQuaid]

I don't think we should add this. This logic will not behave the same as the tap naming logic in Ruby and is likely to further confuse. Instead, let's error out if we get no valid arguments.

[carlocab]

This logic will not behave the same as the tap naming logic in Ruby and is likely to further confuse.

I don't follow. It does use the same tap naming logic as in Ruby. If you mean it allows you to refer to a tap as homebrew/homebrew-core instead of just homebrew/core, then that can be easily removed.

[MikeMcQuaid]

It does use the same tap naming logic as in Ruby.

It's not identical logic and it's not identical code.

I think this is much more easily and reliably fixed by updating documentation and error messaging rather than trying to parse a new format of input consistently.

[BrewTestBot]

Review period ended.

[carlocab]

Instead, let's error out if we get no valid arguments.

Did this partially -- we now error out if any argument is invalid. We can continue if at least one argument is valid, but given that this update-reset is destructive it seems safer to err on not doing anything.

[MikeMcQuaid]

Nice improvements, thanks @carlocab!

[MikeMcQuaid]

Oops, looks like this broke: https://github.com/Homebrew/brew/actions/runs/4293038788/jobs/7480240578#step:8:61

[carlocab]

Oops, looks like this broke: https://github.com/Homebrew/brew/actions/runs/4293038788/jobs/7480240578#step:8:61

Well, now we know that command was quietly not doing anything! 😄

[carlocab]

I've now removed it. I can put it back with the correct path, but given that this has been a silent no-op for a while now I suspect we don't need it.

[MikeMcQuaid]

@carlocab Yup, all good, thanks!