There were a few issues going on here:
- If some operation had invalidated the queues, they were subsequently
recreated with a call to .get_queues() in the undo handling code. This
could happen after the changes to the card had already been reverted,
leading to a queue state that didn't match our expectations.
- More generally, it's not safe to assume our mutations will apply
cleanly after the queue has been rebuilt. The next card will vary
depending on the number of remaining cards when interspersing cards of
different types, and a queue-invalidating operation will have changed
the learning cutoff.
So rather than rebuilding the queues on demand, we now check that they
already exist, and were created at the time we expect. If not, we
invalidate them and skip applying the mutations, and a subsequent
refresh of the UI should rebuild the queues correctly.
As part of this change, the cutoff snapshot has been moved into the
normal answer update object.
One possible downside here is that adding a note during review may cause
a newly due learning card to appear when undoing a different review.
If this proves to be a problem, we could potentially note down the
learning cutoff and apply it when queues are rebuilt later.
Context: https://forums.ankiweb.net/t/more-cards-today-question-about-v3/12400/10
Previously, interday learning cards and reviews were gathered at the
same time in v3, with the review limit being applied to both of them. The
order cards were gathered in would change the ratio of gathered learning
cards and reviews, but as they were displayed together in a single count,
a changing ratio was not apparent, and no special handling was required
by the deck tree code.
Showing interday learning cards in the learning count, while still
applying a review limit to them, makes things more complicated, as
a changing ratio will result in different counts. The deck tree code
is not able to know which order cards will appear in, so without changes,
we would have had a situation where the deck list may show different counts
to those seen when clicking on a deck.
One way to solve this would have been to introduce a separate limit for
interday learning cards. But this would have meant users needed to
juggle two different limits, instead of having a single one that controls
total number of (non-intraday) cards shown.
Instead, the scheduler now fetches interday cards prior to reviews -
the rationale for that order is that learning cards tend to be more
fragile/urgent than reviews. The option to show learning cards
before/after/mixed with reviews still exists, but it applies only after
cards have been capped to the daily limit.
To ensure the deck tree code matches the counts the scheduler gives,
it too applies limits to interday learning cards first, and reviews
afterwards.
Interday learning cards are now counted in the learning count again,
and are no longer subject to the daily review limit.
The thinking behind the original change was that interday learning cards
are scheduled more like reviews, and counting them in the review count
would allow the learning count to focus on intraday learning - the red
number reflecting the fact that they are the most fragile memories. And
counting them together made it practical to apply the review limit
to both at once.
Since the release, there have been a number of users expecting to see
interday learning cards included in the learning count (the latest being
https://forums.ankiweb.net/t/feedback-and-a-feature-adjustment-request-for-2-1-45/12308),
and a good argument can be made for that too - they are, after all, listed
in the learning steps, and do tend to be harder than reviews. Short of
introducing another count to keep track of interday and intraday learning
separately, moving back to the old behaviour seems like the best move.
This also means it is not really practical to apply the review limit to
interday learning cards anymore, as the limit would be split between two
different numbers, and how much each number is capped would depend on
the order cards are introduced. The scheduler could figure this out, but
the deck list code does not know card order, and would need significant
changes to be able to produce numbers that matched the scheduler. And
even if we ignore implementation complexities, I think it would be more
difficult for users to reason about - the influence of the review limit
on new cards is confusing enough as it is.
This makes the review backlog case more expensive, since we end up
shuffling items outside the daily limit, but for the common case it's
about the same speed, and it means we don't need two separate sorting
steps. New cards remain handled the same way, since a backlog
is common there.
Also ensures that interday learning cards honor the deck sorting, and
that the non-default sort orders shuffle at the end.
- Daily limits are no longer inherited - each deck limits its own
cards, and the selected deck enforces a maximum limit.
- Fetching of review cards now uses a single query, and sorts in advance.
In collections with a large number of overdue cards and decks, this is
faster than iterating over each deck in turn.
- Include interday learning count in review count & review limit, and
allow them to be buried.
- Warn when parent review limit is lower than child deck in deck options.
- Cap the new card limit to the review limit.
- Add option to control whether new card fetching short-circuits.
Instead of using a separate undo queue, the code now defers checking for
newly-due learning cards until the answering stage, and logs the updated
cutoff time as an undoable change, so that any newly-due learning cards
won't appear instead of a new/review card that was just undone.
Queue redo now uses a similar approach to undo, instead of rebuilding the
queues.
The original rationale was avoiding a possible O(n) insertion if
the learning card was due outside the cutoff, but the increased code
complexity doesn't seem worth it, given that learning cards will
rarely grow above 1000.
Also added a currently-disabled test that demonstrates the current undo
handling behaviour is yielding incorrect counts; that will be reworked
in the next commit, and this change will make that easier.
- split new card fetch order and subsequent sort order; use latter
when building queues
- default to spacing siblings when burying is off, with options to
show each sibling in turn, and shuffle the fetched cards
The bury new/review flags are now pulled from each card's home deck,
instead of using a global setting that had not been hooked up. This
unfortunately means we need to fetch the map of all decks up front, as
we need to be able to look up a deck configuration for cards that are
in filtered decks.
Fixes a "card was modified" error caused by cards being buried during
review, when they weren't removed up-front.
So, this is fun. Apparently "DeckId" is considered preferable to the
"DeckID" were were using until now, and the latest clippy will start
warning about it. We could of course disable the warning, but probably
better to bite the bullet and switch to the naming that's generally
considered best.
- 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
