BP_Messages_Thread::$last_message_* not populated by default

[jdgrimes]

The BP_Messages_Thread class offers some convenience fields that grant direct access to the data for the last message in the thread:

• last_message_id
• last_message_date
• last_sender_id
• last_message_subject
• last_message_content

However, these are only populated by BP_Messages_Thread_Template::__construct(), and were not documented in BP_Message_Thread until [5999].

This caused me confusion when I was trying to use these fields in a different context. To keep others from spending time chasing this down, I suggest that we do one of the following:

1. Add a note to the inline docs for each of these fields stating that they are only populated when using BP_Messages_Thread_Template.
2. Always populate them inside of the BP_Message_Thread::populate() method.

I favor the latter.

[jdgrimes]

Always populate the fields

[jdgrimes]

I've uploaded 6580.diff​, which always populates the fields. It includes a basic unit test.

[jdgrimes]

Improved unit test

[jdgrimes]

Fixes docblocks of $messages and $recipients fields object -> object[]

[boonebgorges]

Definitely - I don't see any reason not to do this.

Thanks for the patch, jdgrimes.

[boonebgorges]

In 10038:

BP_Messages_Thread objects should always have last_message_* properties set.

Previously, they were only set in the context of a template loop.

Props jdgrimes.
Fixes #6580.