agent_ui: Cache cross-channel thread import check off the render loop

crates/agent_ui/src/thread_import.rs

@@ -60,24 +60,37 @@ impl Dismissable for CrossChannelImportOnboarding {
     const KEY: &'static str = "dismissed-cross-channel-thread-import";
 }
 
-/// Returns the list of non-Dev, non-current release channels that have
-/// at least one thread in their database.  The result is suitable for
-/// building a user-facing message ("from Zed Preview and Nightly").
-pub fn channels_with_threads(cx: &App) -> Vec<ReleaseChannel> {
+pub fn channels_with_threads(cx: &App) -> Task<Vec<SharedString>> {
     let Some(current_channel) = ReleaseChannel::try_global(cx) else {
-        return Vec::new();
+        return Task::ready(Vec::new());
     };
     let database_dir = paths::database_dir();
 
-    ReleaseChannel::ALL
-        .iter()
-        .copied()
-        .filter(|channel| {
-            *channel != current_channel
-                && *channel != ReleaseChannel::Dev
-                && channel_has_threads(database_dir, *channel)
-        })
-        .collect()
+    let channel_has_threads = |database_dir: &std::path::Path, channel: ReleaseChannel| {
+        let db_path = db::db_path(database_dir, channel);
+        if !db_path.exists() {
+            return false;
+        }
+        let connection = sqlez::connection::Connection::open_file(&db_path.to_string_lossy());
+        connection
+            .select_row::<bool>("SELECT 1 FROM sidebar_threads LIMIT 1")
+            .ok()
+            .and_then(|mut query| query().ok().flatten())
+            .unwrap_or(false)
+    };
+
+    cx.background_spawn(async move {
+        ReleaseChannel::ALL
+            .iter()
+            .copied()
+            .filter(|channel| {
+                *channel != current_channel
+                    && *channel != ReleaseChannel::Dev
+                    && channel_has_threads(database_dir, *channel)
+            })
+            .map(|channel| SharedString::new_static(channel.display_name()))
+            .collect()
+    })
 }
 
 #[derive(Clone)]
@@ -658,19 +671,6 @@ fn import_threads_from_other_channels_in(
     .detach();
 }
 
-fn channel_has_threads(database_dir: &std::path::Path, channel: ReleaseChannel) -> bool {
-    let db_path = db::db_path(database_dir, channel);
-    if !db_path.exists() {
-        return false;
-    }
-    let connection = sqlez::connection::Connection::open_file(&db_path.to_string_lossy());
-    connection
-        .select_row::<bool>("SELECT 1 FROM sidebar_threads LIMIT 1")
-        .ok()
-        .and_then(|mut query| query().ok().flatten())
-        .unwrap_or(false)
-}
-
 fn read_threads_from_channel(
     database_dir: &std::path::Path,
     channel: ReleaseChannel,

crates/sidebar/src/sidebar.rs

@@ -780,6 +780,9 @@ pub struct Sidebar {
     /// buttons. This field tracks whether we were using verbose labels so they
     /// can stay stable after dismissing one of the banners.
     import_banners_use_verbose_labels: Option<bool>,
+    /// Display names of other release channels that have threads available to
+    /// import.
+    cross_channel_import_channels: Vec<SharedString>,
 }
 
 impl Sidebar {
@@ -858,6 +861,17 @@ impl Sidebar {
         )
         .detach();
 
+        let channels_with_threads = channels_with_threads(cx);
+        cx.spawn(async move |this, cx| {
+            let channels = channels_with_threads.await;
+            this.update(cx, |this, cx| {
+                this.cross_channel_import_channels = channels;
+                cx.notify();
+            })
+            .ok();
+        })
+        .detach();
+
         let deferred_multi_workspace = multi_workspace.downgrade();
         cx.defer_in(window, move |this, window, cx| {
             if let Some(multi_workspace) = deferred_multi_workspace.upgrade() {
@@ -898,6 +912,7 @@ impl Sidebar {
             _subscriptions: Vec::new(),
             _draft_editor_observations: Vec::new(),
             import_banners_use_verbose_labels: None,
+            cross_channel_import_channels: Vec::new(),
         }
     }
 
@@ -7199,19 +7214,19 @@ impl Sidebar {
     }
 
     fn should_render_cross_channel_import_onboarding(&self, cx: &App) -> bool {
-        !CrossChannelImportOnboarding::dismissed(cx) && !channels_with_threads(cx).is_empty()
+        !CrossChannelImportOnboarding::dismissed(cx)
+            && !self.cross_channel_import_channels.is_empty()
     }
 
     fn render_cross_channel_import_onboarding(
         &mut self,
         verbose_labels: bool,
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
-        let channels = channels_with_threads(cx);
-        let channel_names = channels
+        let channel_names = self
+            .cross_channel_import_channels
             .iter()
-            .map(|channel| channel.display_name())
-            .collect::<Vec<_>>()
+            .map(SharedString::as_str)
             .join(" and ");
 
         let description = format!(

crates/zed/src/zed/open_listener.rs

@@ -2198,6 +2198,7 @@ mod tests {
             .await;
 
         assert!(!errored);
+        cx.run_until_parked();
 
         let multi_workspace = cx.update(|cx| cx.windows()[0].downcast::<MultiWorkspace>().unwrap());
         multi_workspace