current_user_can() bug with Super Admin

[abdessamad idrissi]

If the logged in user is a super admin this returns true;

if (current_user_can('contributor')) echo 'current user is a contributor';

Normally it should return false as it does for administrator, author, editor and subscriber account types.

I spotted this while working in my localhost Multisite install then figured it doesn't work in the live standalone version!

You should not pass role names to current_user_can(); only capabilities.

Also, the only way to test for super-admins is by using is_super_admin().

But in ​the codex;

...this function accepts capability or role name.

The same thing is stated in the wp-includes/capabilities.php

So what to believe?

I don't want to check if user is super admin, I want to check if the user is contributor. Of course there's other techniques to make this happen but I just wanted to report a bug in this function as it fails when it comes to super admins.

I updated the codex page.

From WP_User::has_cap():

		// Multisite super admin has all caps by definition, Unless specifically denied.
		if ( is_multisite() && is_super_admin( $this->ID ) ) {
			if ( in_array('do_not_allow', $caps) )
				return false;
			return true;
		}

current_user_can('contributor') usually works only because role names are mangled up with capability names. We should update the inline docs.

In general, it would be nice to have WP_User->has_role('contributor').

Would be good to update the inline doc too so the codex page won't get wrongly re-modified!

Related: #22624