Closes https://github.com/ppy/osu/issues/28791.
The reason why nudging was not changing hyperdash state in catch was
that `EditorBeatmap.Update()` was not being called on the objects that
were being modified, therefore postprocessing was not performed,
therefore hyperdash state was not being recomputed.
Looking at the usage sites of `EditorBeatmap.PerformOnSelection()`,
about two-thirds of callers called `Update()` themselves on the objects
they mutated, and the rest didn't. I'd say that's the failure of the
abstraction and it should be `PerformOnSelection()`'s responsibility to
call `Update()` there. Yes in some of the cases here this will cause
extraneous calls that weren't done before, but the method is already
heavily disclaimed as 'expensive', so I'd say usability should come
first.
Closes https://github.com/ppy/osu/issues/28369.
The reporter of the issue was incorrect; it's not the beat snap grid
that is causing the problem, it's something far stupider than that.
When the current selection changes,
`EditorSelectionHandler.UpdateTernaryStates()` is supposed to update the
state of ternary bindables to reflect the reality of the current
selection. This in turn will fire bindable change callbacks for said
ternary toggles, which heavily use `EditorBeatmap.PerformOnSelection()`.
The thing about that method is that it will attempt to check whether any
changes were actually made to avoid producing empty undo states, *but*
to do this, it must *serialise out the entire beatmap to a stream* and
then *binary equality check that* to determine whether any changes were
actually made:
7b14c77e43/osu.Game/Screens/Edit/EditorChangeHandler.cs (L65-L69)
As goes without saying, this is very expensive and unnecessary, which
leads to stuff like keeping a selection box active while a taiko beatmap
is playing under it dog slow. So to attempt to mitigate that, add
precondition checks to every single ternary callback of this sort to
avoid this serialisation overhead.
And yes, those precondition checks use linq, and that is *still* faster
than not having them.
By moving this to a central location, we can avoid invoking the
EditorChangeHandler when there is no selection made. This helps
alleviate the issue pointed out in
https://github.com/ppy/osu/issues/11901, but not fix it completely.
