It's very unusual for me to add options to the root group, because:

• I tend to avoid conflicting or meaningless configurations (e.g. passing an option that won't be actually used) so I add a "Group option" only if I'm sure that all present and future subcommands will share such option and this is very rarely the case; good examples are --verbosity and --config
• I like to type all parameters after command names.

What I usually end up to do is defining a class Params where I put shared parameters as class attributes, sometimes using functools.partial if I want to reuse the same parameter with slightly different args in different commands. Not saying it's a better approach, actually yours is the cleaner one probably (but see point 2 in the above list :-)).

Anyway, I generally don't like too much libraries that tell me what I should or not do, so feel free to open a PR. Nonetheless, note that it's very easy to work around the limitation (which is why I took the liberty of not allowing option groups by default):

from cloup import ConstraintMixin, OptionGroupMixin, Group

class MyGroup(OptionGroupMixin, Group):
    pass

@cloup.group(cls=MyGroup)
def cmd:
    ...

If we include OptionGroupMixin, I don't see any reason not to include ConstraintMixin as well. Probably we can add both to BaseCommand directly.

The workaround you proposed indeed does the trick. Thanks for providing a solution! 👍

For the record, this experiments led to the discovery of a bug with command sections that has been filled at #99.

Yes, please. This is definitely a bug. I'll fix it later in the day.

Yes, please. This is definitely a bug. I'll fix it later in the day.

Just moved the bug into its own issue at #99.

Now back to the main topic, a.k.a. option groups on Group.

When I started using Click several years ago, I was taken aback by its way of sharing options in a group. As you pointed out in your second argument, the CLI [options] <subcommand> [more options] pattern is quite rigid and frustrating for users. How may time did I tried to use the CLI <subcommand> [all_my_options] form...

I didn't found an elegant way to allow for arbitrary positions of commands and options, so I followed Click's recommandation called it a day.

But maybe we can revisit this limitation and work around it.

I can't see an easy way. If you want to type options after subcommands, the easiest workaround is what I explained above: reusing options when it's needed. And thinking again about it, I actually prefer this solution to Group parameters:

• I don't need to grab parameters from a dictionary, ctx.parent.params, they are in the function signature
• all options I can pass when using a subcommand are visible in the help of a subcommand.

from functools import partial

class Params:
    shared = option('--shared', ...)
    common = partial(option, '--common', default=1, ...) 

@command()
@Params.shared
@Params.common(required=True)
def foo(shared, common):
    ...

@command()
@Params.shared
@Params.common()
def bar(shared, common):
    ...

Of course this sharing can be extended to Cloup's option groups.

Closing as this is a subset of

• Support option groups and constraints in Group by removing BaseCommand and making Group inherit from Command #112

Thanks @janluke for adding this feature as part of #112 !