Remove vestige add_users capability

[nacin]

Listed in populate_roles_300() and added in [14174], it was never used. The situation it was presumably introduced for now falls on promote_users.

[renoirb]

Remove legacy hook as per proposed

[nacin]

Wondering whether we should go through the trouble of also removing it in an upgrade routine.

[markjaquith]

Four plugins in the repo are using it. Should we yank the actual cap and then map it to promote_users? Either way, I'm thinking that the actual cap should be removed from any roles that have it.

[nacin]

Either way, I'm thinking that the actual cap should be removed from any roles that have it.

Seems fine to me. We can use map_meta_cap to map it to promote_users. Opens us up to adding it in the future.

[nacin]

In [22300]:

Comment that the add_users capability was never used and has its days numbered. see #16719.

[nacin]

Per scrub.

[chriscct7]

Needs patch that removes cap from users and map_meta_cap's the cap as described in comment:2

[Craig Ralston]

16719-1.patch removes add_users legacy cap and maps it to promote_users

[DBrumbaugh10Up]

I think I would like to work on this, I'll take a look at it.

[Craig Ralston]

16719-2.patch refreshes 16719-1.patch

[wonderboymusic]

In 35507:

Roles: map add_users cap to promote_users and remove it.

"Never used, will be removed." - The Ghost of 3.5 Nacin

Props Craig Ralston, renoirb.
Fixes #16719.

[nacin]

It seemed like 3 years ago, @markjaquith and I agreed:

Wondering whether we should go through the trouble of also removing it in an upgrade routine.

I'm thinking that the actual cap should be removed from any roles that have it.

An upgrade routine seems prudent. Please re-close if you disagree.

[boonebgorges]

16179.diff​ introduces the migration routine suggested above.

[dd32]

Noting that I've reviewed the patch, and it looks good to me (assuming it works ;) )

[boonebgorges]

In 35701:

On 4.4 upgrade, remove the unused 'add_users' cap from all roles.

Fixes #16719.

[havahula]

Not sure if this is the right place but it would be good to update the codex on this one:
​https://codex.wordpress.org/Roles_and_Capabilities#add_users