This splits update_card() into separate undoable/non-undoable ops
like the change to notes in b4396b94abdeba3347d30025c5c0240d991006c9
It means that actions get a blanket 'Update Card' description - in the
future we'll probably want to either add specific actions to the backend,
or allow an enum or string to be passed in to describe the op.
Other changes:
- card.flush() can no longer be used to add new cards. Card creation
is only supposed to be done in response to changes in a note's fields,
and this functionality was only exposed because the card generation
hadn't been migrated to the backend at that point. As far as I'm aware,
only Arthur's "copy notes" add-on used this functionality, and that should
be an easy fix - when the new note is added, the associated cards will
be generated, and they can then be retrieved with note.cards()
- tidy ups/PEP8
To coalesce successive note edits into a single undo op we'll need to
be able to get the original Undoable type, which is awkward to do with
a trait object.
- note.flush() behaves like before, as otherwise actions or add-ons
that perform bulk flushing would end up creating an undo entry for
each note
- added col.update_note() to opt in to the new behaviour
- tidy up the names of some related routines
- transact() now automatically clears card queues unless an op
opts-out (and currently only AnswerCard does). This means there's no
risk of forgetting to clear the queues in an operation, or when undoing/
redoing
- CollectionOp->UndoableOp
- clear queues when redoing "answer card", instead of clearing redo
when clearing queues
Reviews and operations on the backend that support undoing can now be
committed immediately, so they will not be lost in the event of a crash.
This required tweaks to a few places:
- don't set collection mtime on save() unless changes were made in
Python, as otherwise we end up accidentally clearing the backend undo
queue
- autosave() is now run on every reset()
- garbage collection now runs in a timer, instead of relying on
autosave() to be run periodically
- use dataclasses for the review/checkpoint undo cases, instead of the
nasty ad-hoc list structure
- expose backend review undo to Python, and hook it into GUI
- redo is not currently exposed on the GUI, and the backend can only
cope with reviews done by the new scheduler at the moment
- the initial undo prototype code was bumping mtime/usn on undo, but
that was not ideal, as it was breaking the queue handling which expected
the mtime to match. The original rationale for bumping mtime/usn was
to avoid problems with syncing, but various operations like removing
a revlog can't be synced anyway - so we just need to ensure we clear the
undo queue prior to syncing
- fetch sfld and csum when fetching notes, to make it cheaper
to write them back out unmodified
- make `fields` private, and access it via accessors, so we can
still catch when fields have been mutated without calling
prepare_for_update()
- fix python importing code passing a string in as the checksum
