Before this rev., the field widget 'mail_activity' kept an internal
cache of fetched activities (like the 'mail_thread' and
'mail_followers'). However, for activities, this cache may cause
issues.
For instance, create a new lead in 'My pipeline', schedule a
'Meeting' activity on that lead (it opens the Calendar view so
that real meetings can be created), create a meeting 2 weeks from
now, go back to the lead form view: the activity still diplays that
the meeting is today (when the view is refreshed, the correct date
is displayed).
This rev. removes the internal cache for this field widget, as the
activities can easily be updated in business flows (unlike messages
or followers).
This rev. also fixes a bug in the BasicModel, where the res_ids of
a list datapoint was altered in place to return a list of x2many
commands instead of the list of ids when being stringified. This
caused a traceback when opening a lead with activities, as soon
as the internal cache had been removed.
Aaron Bohy
3809fc891f