Default User Role isn't checked against defined roles, causing unexpected resets to Administrator

[Ivolution]

Take these steps:

1. Activate a plugin that creates role on activation. For example, it calls "add_role( 'photo_uploader', 'Photo Uploader', array( 'read') );"
   
2. In General Settings, set the Default User Role to this new role, 'Photo Uploader'.
   
3. Deactivate the plugin, removing the roles: "remove_role( 'photo_uploader');"
   
4. In General Settings, the Default User Role now displays 'Administrator'. (In the database, it still says 'photo_uploader'.)
   
5. When creating a new user (as admin), the role dropdown-box now displays 'Administrator' as role for this new user. This new user _will_ have role 'Administrator' if an unsuspecting admin does not explicitly alter the role in the dropdown-box.
   

This way, an unsuspecting adminstrator might accidentally create new admins for his blog.

I have also tested this for new users registering themselves. Fortunately, they are assigned the role 'None', not 'Administrator'.

Greetings,

Ivo van der Linden
(employee of LaQuSo @ Eindhoven University of Technology)

[dd32]

We should probably check on remove_role() to see if it's the default role, and if so, revert back to subscriber in that case (Assuming the role exists)

[nacin]

We should probably reverse the results from get_editable_roles() there, so they are listed in ascending order (for the default roles).

Dion's take definitely makes sense. We could also drop a filter in the options API to verify the role's existence that way (as roles aren't always stored in the DB), or just stick an update_option call in options-general right before the role dropdown. Cheap, but effective here and elsewhere.

[garyc40]

reverse role dropdown list, add a verification filter for 'default_role', update 'default_role' when remove_role()

[wonderboymusic]

Patch refreshed against trunk excludes the PHP4 by-ref nonsense

[wonderboymusic]

14578.2.diff​ is fuzz-less

[nacin]

Hmm, looking at it again, this might be better on save? Agree with the rest, though.

[nacin]

In 25695:

Reverse the order of roles in wp_dropdown_roles(). Reset to 'subscriber' when the default role is removed and when a save is invalid.

props garyc40, wonderboymusic.
fixes #14578.

[nofearinc]

#15636 was marked as a duplicate.