[4.0] Multilang: com_associations broken for contacts and newsfeeds

[infograf768]

See #20692 (comment)

Steps to reproduce the issue

Create a multilingual site.
Create at least a contact and a newsfeed tagged to one of the content languages
Load multilingual associations, choose the contact or the newsfeed as type + its corresponding language.

Notice: Trying to get property of non-object in /Applications/MAMP/htdocs/installmulti/joomla40/administrator/components/com_associations/Helper/AssociationsHelper.php on line 578

Click on the item to load the side by side page
Undefined index: language in /Applications/MAMP/htdocs/installmulti/joomla40/administrator/components/com_associations/Field/ItemlanguageField.php on line 55

Close the side by side
Call to a member function checkin() on null

For the moment, com_contact and com_newsfeeds still use their associations helper in the /helpers/ folder.
As @laoneo says, it may not be related to Services.

Menu items, articles and categories do work OK in com_associations.

[wilsonge]

EDIT: REMOVED AS COMMENTED ON WRONG ISSUE

[infograf768]

@wilsonge
You may be confusing this with #21165 which does concern categories for these components in frontend.

This one here concerns only single contacts or newsfeeds.

Note: as of today July 18th, the errors are a bit different (although same concern)

[18-Jul-2018 07:49:14 Europe/Berlin] PHP Notice:  Trying to get property of non-object in /Applications/MAMP/htdocs/installmulti/joomla40/administrator/components/com_associations/Helper/AssociationsHelper.php on line 581
[18-Jul-2018 07:49:14 Europe/Berlin] PHP Notice:  Undefined index: name in /Applications/MAMP/htdocs/installmulti/joomla40/administrator/components/com_associations/Helper/AssociationsHelper.php on line 257
[18-Jul-2018 07:49:14 Europe/Berlin] PHP Notice:  Undefined index: id in /Applications/MAMP/htdocs/installmulti/joomla40/administrator/components/com_associations/Helper/AssociationsHelper.php on line 292
[18-Jul-2018 07:49:14 Europe/Berlin] PHP Notice:  Undefined index: id in /Applications/MAMP/htdocs/installmulti/joomla40/administrator/components/com_associations/Helper/AssociationsHelper.php on line 294
[18-Jul-2018 07:49:14 Europe/Berlin] PHP Notice:  Undefined index: id in /Applications/MAMP/htdocs/installmulti/joomla40/administrator/components/com_associations/Helper/AssociationsHelper.php on line 295
[18-Jul-2018 07:49:14 Europe/Berlin] PHP Notice:  Trying to get property of non-object in /Applications/MAMP/htdocs/installmulti/joomla40/administrator/components/com_associations/Helper/AssociationsHelper.php on line 621
[18-Jul-2018 07:49:14 Europe/Berlin] PHP Notice:  Trying to get property of non-object in /Applications/MAMP/htdocs/installmulti/joomla40/administrator/components/com_associations/Helper/AssociationsHelper.php on line 621

[wilsonge]

PR in #21171