A probe against the live 0.16.19 says a one-off event comes back from an
expanded query as id "eaaaaai" with baseEventId "i" — an instance id of
its own, and a base that is a different event. The clause that treated a
differing base as an occurrence of a series would therefore have gone on
calling every event recurring, which was the bug.
So recurrence rules alone decide it. What that gives up is an expanded
instance that arrives without its rules attached; whether Stalwart does
that is still to be checked against a real series.
A one-time event opened for editing said "this is a recurring event —
changes apply to the whole series", and deleting one offered to delete
all occurrences of an event that has exactly one.
Three places asked whether an event had a baseEventId and took that for
recurrence. It isn't: the calendar loads its range with expandRecurrences,
and Stalwart puts a baseEventId on everything it returns that way, a
one-off pointing at itself included. The mock never sets the field at
all, which is why this only showed up against a real server.
They now share isRecurring(), which asks about recurrence rules, and
treats a base that is some other event as an occurrence of a series too
— so an expanded instance that travels without its rules is still
described honestly on the way to being deleted.
Fixes#25
jcoffey-dev