current_user_can_for_blog() doesn't use map_meta_cap for multisite user admins

[jamescollins]

[12796] introduced a new current_user_can_for_blog() function, which was based on how the existing current_user_can() function was implemented.

This included this check:

if( is_multisite() && is_super_admin() ) 
    return true;

Then in [13270]/#12109, the current_user_can() function was modified so that map_meta_cap is always used for multisite user admins.

However this change didn't include the necessary change to the current_user_can_for_blog() function as well.

This means that currently the current_user_can_for_blog() will always return true for multisite user admins, without map_meta_cap ever being used.

Patch attached.

[jamescollins]

Patch against trunk r15811

[jamescollins]

I realise we're close to 3.1 feature freeze, but it would be great if we could get this change committed so its included in 3.1.

Thanks.

[nacin]

This looks like a bug, so it would be unaffected by the freeze.

Setting to 3.0.2 actually.

[nacin]

(In [15812]) Use map_meta_cap for multisite super admins in current_user_can_for_blog. props jamescollins, see #15122.

[jamescollins]

nacin, if this has a 3.0.2 milestone doesn't it need to be committed to the 3.0 branch as well as trunk?

Thanks.

[nacin]

Wasn't sure if I wanted to apply it to 3.0.2. This isn't a function that's actually used in core, and it doesn't look like it's used in any plugins based on a quick site:plugins.svn.wordpress.org search on Google. I suppose we should apply it to 3.0, because it will return incorrect (though not truly disastrous) results.

[jamescollins]

nacin, it would be good to either set the milestone of this ticket to 3.1, or commit this fix to the 3.0 branch.

Thanks.

[nacin]

Sure thing.

[nacin]

(In [16631]) Use map_meta_cap for multisite super admins in current_user_can_for_blog. props jamescollins, fixes #15122 for 3.0.