Activity completion "Expect Completed on" function doesn't add entry to Calendar/Timeline block

Hi,

It has been observed that the 'dialouge' activity does not add calendar/timeline block entries whenever the activity is set to use the 'Expect completion by' function of Activity Completion.

It appears the Moodle core code might not automatically handle adding entries to the calendar via this field, so requires plugins to explicitly update '\core_completion\api::update_completion_date_event' instead. This was noted elsewhere for the Checklist activity via https://tracker.moodle.org/browse/CONTRIB-8344 where the following code was required to be added for it, for example: https://github.com/davosmith/moodle-checklist/commit/c2edd07cd27a8c20e80e640b5234d990185b744d.patch

Not sure if that is relevant or applicable in this case, but thought I'd mention it.

STEPS TO REPLICATE:

Ensure either/both the Calendar/Timeline block is added to your testing course. Activity Completion should also be enabled and tracked within this test course per the course settings.
Add a new dialouge activity. Under Activity Completion, set 'Completion tracking' to 'Students can manually mark the activity as completed' and set the 'Expect completion by' date to the next day. Leave all other settings default. Save and return to course.
Look at the Calendar/timeline block and observe there is no entry listed for the date specified.

===== Further note:

It would be best to handle this more like how other core modules (ex: Quiz) handles this:

$completionexpected = (!empty($quiz->completionexpected)) ? $quiz->completionexpected : null;
\core_completion\api::update_completion_date_event($quiz->coursemodule, 'quiz', $quiz->id, $completionexpected);

The checklist method actually means you can never make the calendar event go away by unticking 'Expect completion by'. The way the Quiz does it means it can be un-set via the applicable tick-box, which would be the preferable outcome.

danmarsden / moodle-mod_dialogue

Activity completion "Expect Completed on" function doesn't add entry to Calendar/Timeline block #106