fix(cef): isolate embedded browser close on macOS

crates/tauri-runtime-cef/src/cef_impl/client/life_span.rs

@@ -2,7 +2,11 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-License-Identifier: MIT
 
-use std::sync::{Arc, mpsc::Sender};
+use std::sync::{
+  Arc,
+  atomic::{AtomicI32, Ordering},
+  mpsc::Sender,
+};
 
 use cef::*;
 use tauri_runtime::{
@@ -14,6 +18,21 @@ use winit::event_loop::EventLoopProxy as WinitEventLoopProxy;
 
 use crate::runtime::{CefRuntime, Message, NewWindowOpener, RuntimeContext};
 
+const UNREGISTERED_BROWSER_ID: i32 = -1;
+
+fn register_primary_browser(primary_browser_id: &AtomicI32, browser_id: i32) {
+  let _ = primary_browser_id.compare_exchange(
+    UNREGISTERED_BROWSER_ID,
+    browser_id,
+    Ordering::AcqRel,
+    Ordering::Acquire,
+  );
+}
+
+fn should_isolate_browser_close(primary_browser_id: &AtomicI32, browser_id: i32) -> bool {
+  primary_browser_id.load(Ordering::Acquire) == browser_id
+}
+
 // There is some race condition on CEF that causes the app loading to fail
 // when there is a network service crash:
 // "[85296:47750637:0127/131203.017395:ERROR:content/browser/network_service_instance_impl.cc:610] Network service crashed or was terminated, restarting service."
@@ -52,20 +71,49 @@ wrap_life_span_handler! {
     proxy: WinitEventLoopProxy,
     window_id: WindowId,
     webview_id: u32,
+    primary_browser_id: Arc<AtomicI32>,
     context: RuntimeContext<T>,
     new_window_handler: Option<Arc<tauri_runtime::webview::NewWindowHandler<T, CefRuntime<T>>>>,
     initial_url: Option<String>,
   }
 
   impl LifeSpanHandler {
     fn on_after_created(&self, browser: Option<&mut Browser>) {
+      if let Some(browser) = browser.as_deref() {
+        register_primary_browser(&self.primary_browser_id, browser.identifier());
+      }
+
       if let Some(browser) = browser
         && let Some(initial_url) = &self.initial_url
       {
         check_and_reload_if_blank(browser.clone(), initial_url.clone());
       }
     }
 
+    #[cfg(target_os = "macos")]
+    fn do_close(&self, browser: Option<&mut Browser>) -> std::os::raw::c_int {
+      let Some(browser) = browser else {
+        return 0;
+      };
+      if !should_isolate_browser_close(&self.primary_browser_id, browser.identifier()) {
+        return 0;
+      }
+
+      if self
+        .sender
+        .send(Message::BrowserCloseReady(self.webview_id))
+        .is_err()
+      {
+        return 0;
+      }
+      self.proxy.wake_up();
+
+      // CEF's default result sends performClose:/WM_CLOSE/delete_event to the
+      // top-level parent. Tauri owns that window, so the runtime tears down
+      // only this browser's native child view instead.
+      1
+    }
+
     fn on_before_popup(
       &self,
       _browser: Option<&mut Browser>,
@@ -136,3 +184,31 @@ wrap_life_span_handler! {
     }
   }
 }
+
+#[cfg(test)]
+mod tests {
+  use std::sync::atomic::AtomicI32;
+
+  use super::{register_primary_browser, should_isolate_browser_close};
+
+  #[test]
+  fn isolates_only_the_runtime_owned_child_browser() {
+    let primary_browser_id = AtomicI32::new(-1);
+
+    register_primary_browser(&primary_browser_id, 41);
+
+    assert!(should_isolate_browser_close(&primary_browser_id, 41));
+    assert!(!should_isolate_browser_close(&primary_browser_id, 42));
+  }
+
+  #[test]
+  fn popup_creation_does_not_replace_the_primary_browser() {
+    let primary_browser_id = AtomicI32::new(-1);
+
+    register_primary_browser(&primary_browser_id, 41);
+    register_primary_browser(&primary_browser_id, 42);
+
+    assert!(should_isolate_browser_close(&primary_browser_id, 41));
+    assert!(!should_isolate_browser_close(&primary_browser_id, 42));
+  }
+}

crates/tauri-runtime-cef/src/cef_impl/client/mod.rs

@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-License-Identifier: MIT
 
-use std::sync::{Arc, Mutex, mpsc::Sender};
+use std::sync::{Arc, Mutex, atomic::AtomicI32, mpsc::Sender};
 
 use cef::*;
 use tauri_runtime::{UserEvent, window::WindowId};
@@ -71,6 +71,7 @@ wrap_client! {
     pub(crate) window_id: WindowId,
     pub(crate) webview_id: u32,
     pub(crate) label: String,
+    primary_browser_id: Arc<AtomicI32>,
     initial_url: Option<String>,
     devtools_enabled: bool,
     drag_drop_event_target: DragDropEventTarget,
@@ -107,6 +108,7 @@ wrap_client! {
         self.proxy.clone(),
         self.window_id,
         self.webview_id,
+        self.primary_browser_id.clone(),
         self.context.clone(),
         self.handlers.new_window_handler.clone(),
         self.initial_url.clone(),

crates/tauri-runtime-cef/src/platform/macos/webview.rs

@@ -72,6 +72,10 @@ impl AppWebview {
     nsview.setHidden(!visible);
   }
 
+  pub(crate) fn destroy_native_view(&self) {
+    self.nsview().removeFromSuperview();
+  }
+
   pub(crate) fn apply_physical_bounds(&self, scale: f64, x: i32, y: i32, width: i32, height: i32) {
     let nsview = self.nsview();
     let Some(parent) = (unsafe { nsview.superview() }) else {

crates/tauri-runtime-cef/src/runtime.rs

@@ -308,6 +308,8 @@ pub(crate) type AfterWindowCreationCallback = Box<dyn for<'a> Fn(RawWindow<'a>)
 
 pub(crate) enum Message<T: UserEvent> {
   EventLoop(EventLoopMessage),
+  #[cfg(target_os = "macos")]
+  BrowserCloseReady(u32),
   BrowserClosed(WindowId, u32),
   Opened(Vec<url::Url>),
   #[cfg(target_os = "macos")]
@@ -501,6 +503,18 @@ impl<T: UserEvent> WinitCefApp<T> {
   fn handle_message(&mut self, event_loop: &dyn ActiveEventLoop, message: Message<T>) {
     match message {
       Message::EventLoop(message) => self.handle_event_loop_message(event_loop, message),
+      #[cfg(target_os = "macos")]
+      Message::BrowserCloseReady(webview_id) => {
+        if let Some(child) = self
+          .state
+          .windows
+          .values()
+          .flat_map(|appwindow| &appwindow.children)
+          .find(|child| child.webview_id == webview_id)
+        {
+          child.destroy_native_view();
+        }
+      }
       Message::BrowserClosed(_window_id, webview_id) => {
         // Standalone webview.close() keeps the child in state until this
         // callback, so cleanup happens here. Window/app teardown removes child

crates/tauri-runtime-cef/src/webview.rs

@@ -374,6 +374,7 @@ impl<T: UserEvent> WinitCefApp<T> {
       window_id,
       webview_id,
       pending.label.clone(),
+      Arc::new(AtomicI32::new(-1)),
       Some(pending.url.as_str().to_string()),
       devtools_enabled,
       drag_drop_event_target,