12.x: set group expiration date at users_usergroups table when user selects the group at registration time OR through PluginSubscribeGroup OR through PluginMemberlist

• Conflict of two features (each works well independently)
• Consistency
• Error

When you set some expiry time for a group membership (through the admin groups interface), this information is stored in mysql table users_usergroups, and this is taken into account when you use PluginMemberPayment.

However, in other cases of letting a user join a group which has some expiry date set, that information (expiry date) is not stored at mysql table users_usergroups as expected.

Reproduced here:
http://xavi-9794-5946.show.tikiwiki.org/tiki-index.php?page=HomePage
u: admin
p: 12345

You can also test with a few users already created:
u: foo1
p: 12345

or
u: user1
p: user1

Cases:

a) Through usual Registration

if you set some group to be selected at registration time
You can register a new user to test case (a), and select either Group1 or Group2 at registration time (both have expiry date 2 days later):
http://xavi-9794-5946.show.tikiwiki.org/tiki-register.php

b) Through Plugin subscribegroup

if the user clicks at PluginSubscribeGroup (with perms and site config set up appropriately),
http://xavi-9794-5946.show.tikiwiki.org/tiki-index.php?page=HomePage#Plugin_subscribegroup

c) Through Plugin MemberList

if the user selects to join him/herself thorugh PluginMemberList
(with perms and site config set up appropriately), or the admin join a user to that group
http://xavi-9794-5946.show.tikiwiki.org/tiki-index.php?page=HomePage#PluginMemberList

However, looking at the user through tiki-assignuser.php?assign_user=foo , the right expiry information is shown.
http://xavi-9794-5946.show.tikiwiki.org/tiki-assignuser.php?assign_user=foo1

But if you use PluginGroupExpiry (which looks for that date at table users_usergroups) no date is found and it reports back that the group membership never expires.
http://xavi-9794-5946.show.tikiwiki.org/tiki-index.php?page=HomePage#PluginGroupExpiry_info

In addition, it seems that someone already noticed that type of issue, and this comment can be found in lib/userslib.php > function get_extend_until_info:

(...)
	function get_extend_until_info($user, $group, $periods = 1)
	{
		//use these functions to get current expiry dates for existing members - they are calculated in some cases
		//so just grabbing the "expire" field from the users_usergroups table doesn't always work
(...)

Update :

• this issue seems to be fixed in Tiki 15.x (as of r58705, at least). The 3 use cases work as expected (nice!). The extra code in 15.x would need to be backported to 12.x, I guess.
• Assign user to groups has got a regression in 15.x: you cannot see (nor even edit) the group expiry date through the standard user administration UI in 15.x: when you click in "add or remove from a group" in 15.x, you are sent in a modal to this type of url:
  tiki-ajax_services.php?controller=user&action=manage_groups&checked=foo1&all_groups%5B0%5D=Admins&all_groups%5B1%5D=Anonymous&all_groups%5B2%5D=Group1&all_groups%5B3%5D=Group2&all_groups%5B4%5D=Registered&offset=0&sort_mode=login_asc&numrows=25&modal=1
  
  and no expiry information is shown.
  
  While in Tiki12, you are sent to:
  tiki-assignuser.php?assign_user=foo1
  
  This has been added as a new bug report, since it's another issue (regression):
  item5953

This bug has been demonstrated on show2.tiki.org

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This bug has been demonstrated on show.tikiwiki.org

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