I refuse to sleep until I have found a solution to this, which is unfortunate, as it means I may never sleep again 🥲
I've now officially arrived in crazy town, and started wrapping UINavigationController myself.
What's interesting is that the SwiftUI environment is still automatically adding nav items to the controller, so I've actually got the same broken animations as with NavigationStack. At least it’s…consistent.
Running out of ideas now 😅
Hallelujah! 🙌
Finally got a workaround for the NavigationSplitView regression in iOS 16.4.
Transitions stop working when the content column no longer contains a List (say you have a “Select Mailbox" view, a Grid, etc).
Here's a gist of the issue: https://gist.github.com/phillipcaudell/6d4d0efac6a22cd42bf75f3acd7a033b
It seems to suddenly start behaving like a NavigationStack, which is why adding a navigationDestination sorta works (except now you've got wonky nav animations, and it still sometimes fails)…
…so instead, I'm switching to a Stack when compact. Only issue is getting NavigationLink, SplitView and Stack to play together.
In the end I found it was easier to remove NavigationLinks all together, and instead use tags. Lists then use this as their selection value.
Then, using those selections, I'm computing a path to drive the Stack. Once I caught EditMode, it all worked.
No jittery toolbars. Smooth transitions. Consistent and predictable across iPhone/iPad/Mac.
Thank god.
If there's any poor souls stumbling across this in the future, here's a gist to my solution: https://gist.github.com/phillipcaudell/085580a9412284f381a4730930c7d52f
Now to refactor this back into Big Mail 🥲 #SwiftUI
Okay, another update on my Navigation Saga, because sharing is caring.
After integrating, I noticed selected rows wouldn't unselect when popping back.
Turns out using .tags() will only work if:
1) The root List is bound directly to an ObservedObject. A Binding to the same value in an ObservableObject won't work.
2) The List must only contain Text or Label views (so no pinned Grid at the top).
I'm also not sure why the Binding gets fired so many times VS the ObservedObject either? #SwiftUI
Anyways I'm back to use NavigationLinks(value:) again, which this time seems to be behaving.
I think the reason it wasn't working last time is because I had installed a navigationDestination on my Sidebar (which is shared between compact and regular size class). It looks like it was confusing NavigationSplitView.
Now I have the navigationDestination installed just in the compact size class, and things seem okay…