[macOS] Plugin paincs when calling ns_view.window() in Window::open_parented

[JouderMin]

I am working on a fork of nih-plug-webview, trying to make recent version of wry work with baseview.

But when I try to construct a window handler by wry::WebViewBuilder::build_as_child in baseview::Window::open_parented, the plugin panics!

Through the panic logs, I found wry will call ns_view.window().unwrap(), and it is where the plugin panics.

[prokopyl]

Hi! Which version of baseview are you using?
We had some recent changes with how WindowHandles are built on macOS, so perhaps it fixes that issue?

[JouderMin]

I used baseview base on 3dcd681, which commited on May 20, 2026. I just try fcd1378, the issue still exists.

[JouderMin]

Hi. I just read the code about how WindowHanler are built on macOS, I found parent_view.addSubview(&ns_view); was called after build function was called. No wounder ns_view.window().unwrap() crash, the ns_view had not be attached to the parent view yet.

So I try to make a change like this:

if let Some(parent_view) = parent_view {
    parent_view.addSubview(&ns_view);
}

let window_handle = Self::init(window_inner, window_info, build);

And it crash again. Here are some parts of logs

Thread 0 Crashed:: MainThread Dispatch queue: com.apple.main-thread
0   gain                          	       0x1330dabb4 alloc::rc::RcInnerPtr::strong::h059c6eba199c4e80 + 28
1   gain                          	       0x1330dab20 alloc::rc::RcInnerPtr::inc_strong::h91bfc6138c7c8ddc + 36
2   gain                          	       0x1330dad6c _$LT$alloc..rc..Rc$LT$T$C$A$GT$$u20$as$u20$core..clone..Clone$GT$::clone::h36462ae981596705 + 32
3   gain                          	       0x1330de864 baseview::macos::window::WindowState::from_view::h6741581437b21b5b + 180
4   gain                          	       0x1330da104 baseview::macos::view::view_did_change_backing_properties::h10a828928398603d + 76
5   AppKit                        	       0x18510a610 _NSViewHierarchyDidChangeBackingProperties + 236
6   AppKit                        	       0x18510342c -[NSView addSubview:] + 428

It seems when parent_view.addSubview(&ns_view); was called, the WindowState must be initialized, which we all knew it would be initialized in Self::init.

So, it's a deadlock.

[prokopyl]

I'm working on a PR that better handles how the NSView subclass is initialized (among other things): #262

Can you tell me if this works better for you?

[JouderMin]

OMG! It finally works! Thank you for your gorgeous work!

[prokopyl]

I'm closing this, now that is fixed by #262 which has been merged, and it's also part of the 0.1.2 release. 🙂