fix multithread

web/src/lib.rs

@@ -31,30 +31,6 @@ impl MonotonicClock for CustomTimeProvider {
 
 define_time_provider!(CustomTimeProvider);
 
-/// Returns the preferred WebGPU/WebGL backend, selected with
-/// `?backend=webgpu` / `?backend=webgl` in the page URL.
-#[cfg(target_family = "wasm")]
-fn requested_backend() -> gpui_platform::WebBackendPreference {
-    let search = web_sys::window()
-        .and_then(|window| window.location().search().ok())
-        .unwrap_or_default();
-    if search
-        .trim_start_matches('?')
-        .split('&')
-        .any(|parameter| parameter == "backend=webgpu")
-    {
-        gpui_platform::WebBackendPreference::WebGpu
-    } else if search
-        .trim_start_matches('?')
-        .split('&')
-        .any(|parameter| parameter == "backend=webgl")
-    {
-        gpui_platform::WebBackendPreference::WebGl
-    } else {
-        gpui_platform::WebBackendPreference::Auto
-    }
-}
-
 thread_local! {
     static APPLICATION: RefCell<Option<ApplicationHandle>> = const { RefCell::new(None) };
 }
@@ -120,10 +96,13 @@ pub async fn run() -> Result<(), JsValue> {
         // immediately instead of waiting for a repaint.
         assets.preload().await;
 
-        // Multithreaded web: background work (image decoding, network
-        // fetches, CPU-heavy tasks) runs on real worker threads instead of
-        // the main thread, so the UI stays responsive.
-        gpui_platform::application_with_web_backend(requested_backend()).with_assets(assets)
+        // NOTE: the multithreaded web backend (application_with_web_backend)
+        // cannot host this app's backend. gpui's wasm background workers
+        // block on `Atomics.wait` while idle, freezing their JS event loop,
+        // so `spawn_local`-driven tasks (nostr-sdk's client actor, the
+        // WebSocket transport) and fetch promises never make progress on a
+        // worker thread. Everything must run on the main thread.
+        gpui_platform::single_threaded_web().with_assets(assets)
     };
 
     let launch = move |cx: &mut App| {