remote: Fix toolchain RPC messages not being handled because of the entity getting dropped (#36665)

Release Notes:

- N/A

crates/project/src/toolchain_store.rs

@@ -34,7 +34,10 @@ enum ToolchainStoreInner {
         Entity<LocalToolchainStore>,
         #[allow(dead_code)] Subscription,
     ),
-    Remote(Entity<RemoteToolchainStore>),
+    Remote(
+        Entity<RemoteToolchainStore>,
+        #[allow(dead_code)] Subscription,
+    ),
 }
 
 impl EventEmitter<ToolchainStoreEvent> for ToolchainStore {}
@@ -65,10 +68,12 @@ impl ToolchainStore {
         Self(ToolchainStoreInner::Local(entity, subscription))
     }
 
-    pub(super) fn remote(project_id: u64, client: AnyProtoClient, cx: &mut App) -> Self {
+    pub(super) fn remote(project_id: u64, client: AnyProtoClient, cx: &mut Context<Self>) -> Self {
-        Self(ToolchainStoreInner::Remote(
+        let entity = cx.new(|_| RemoteToolchainStore { client, project_id });
-            cx.new(|_| RemoteToolchainStore { client, project_id }),
+        let _subscription = cx.subscribe(&entity, |_, _, e: &ToolchainStoreEvent, cx| {
-        ))
+            cx.emit(e.clone())
+        });
+        Self(ToolchainStoreInner::Remote(entity, _subscription))
     }
     pub(crate) fn activate_toolchain(
         &self,
@@ -80,8 +85,8 @@ impl ToolchainStore {
             ToolchainStoreInner::Local(local, _) => {
                 local.update(cx, |this, cx| this.activate_toolchain(path, toolchain, cx))
             }
-            ToolchainStoreInner::Remote(remote) => {
+            ToolchainStoreInner::Remote(remote, _) => {
-                remote.read(cx).activate_toolchain(path, toolchain, cx)
+                remote.update(cx, |this, cx| this.activate_toolchain(path, toolchain, cx))
             }
         }
     }
@@ -95,7 +100,7 @@ impl ToolchainStore {
             ToolchainStoreInner::Local(local, _) => {
                 local.update(cx, |this, cx| this.list_toolchains(path, language_name, cx))
             }
-            ToolchainStoreInner::Remote(remote) => {
+            ToolchainStoreInner::Remote(remote, _) => {
                 remote.read(cx).list_toolchains(path, language_name, cx)
             }
         }
@@ -112,7 +117,7 @@ impl ToolchainStore {
                 &path.path,
                 language_name,
             )),
-            ToolchainStoreInner::Remote(remote) => {
+            ToolchainStoreInner::Remote(remote, _) => {
                 remote.read(cx).active_toolchain(path, language_name, cx)
             }
         }
@@ -234,13 +239,13 @@ impl ToolchainStore {
     pub fn as_language_toolchain_store(&self) -> Arc<dyn LanguageToolchainStore> {
         match &self.0 {
             ToolchainStoreInner::Local(local, _) => Arc::new(LocalStore(local.downgrade())),
-            ToolchainStoreInner::Remote(remote) => Arc::new(RemoteStore(remote.downgrade())),
+            ToolchainStoreInner::Remote(remote, _) => Arc::new(RemoteStore(remote.downgrade())),
         }
     }
     pub fn as_local_store(&self) -> Option<&Entity<LocalToolchainStore>> {
         match &self.0 {
             ToolchainStoreInner::Local(local, _) => Some(local),
-            ToolchainStoreInner::Remote(_) => None,
+            ToolchainStoreInner::Remote(_, _) => None,
         }
     }
 }
@@ -415,6 +420,8 @@ impl LocalToolchainStore {
             .cloned()
     }
 }
+
+impl EventEmitter<ToolchainStoreEvent> for RemoteToolchainStore {}
 struct RemoteToolchainStore {
     client: AnyProtoClient,
     project_id: u64,
@@ -425,11 +432,13 @@ impl RemoteToolchainStore {
         &self,
         project_path: ProjectPath,
         toolchain: Toolchain,
-        cx: &App,
+        cx: &mut Context<Self>,
     ) -> Task<Option<()>> {
         let project_id = self.project_id;
         let client = self.client.clone();
-        cx.background_spawn(async move {
+        cx.spawn(async move |this, cx| {
+            let did_activate = cx
+                .background_spawn(async move {
                     let path = PathBuf::from(toolchain.path.to_string());
                     let _ = client
                         .request(proto::ActivateToolchain {
@@ -447,6 +456,14 @@ impl RemoteToolchainStore {
                         .log_err()?;
                     Some(())
                 })
+                .await;
+            did_activate.and_then(|_| {
+                this.update(cx, |_, cx| {
+                    cx.emit(ToolchainStoreEvent::ToolchainActivated);
+                })
+                .ok()
+            })
+        })
     }
 
     pub(crate) fn list_toolchains(

crates/remote_server/src/headless_project.rs

@@ -46,6 +46,9 @@ pub struct HeadlessProject {
     pub languages: Arc<LanguageRegistry>,
     pub extensions: Entity<HeadlessExtensionStore>,
     pub git_store: Entity<GitStore>,
+    // Used mostly to keep alive the toolchain store for RPC handlers.
+    // Local variant is used within LSP store, but that's a separate entity.
+    pub _toolchain_store: Entity<ToolchainStore>,
 }
 
 pub struct HeadlessAppState {
@@ -269,6 +272,7 @@ impl HeadlessProject {
             languages,
             extensions,
             git_store,
+            _toolchain_store: toolchain_store,
         }
     }
 

crates/toolchain_selector/src/active_toolchain.rs

@@ -38,7 +38,6 @@ impl ActiveToolchain {
                         .ok()
                         .flatten();
                     if let Some(editor) = editor {
-                        this.active_toolchain.take();
                         this.update_lister(editor, window, cx);
                     }
                 },
@@ -124,16 +123,6 @@ impl ActiveToolchain {
         if let Some((_, buffer, _)) = editor.active_excerpt(cx)
             && let Some(worktree_id) = buffer.read(cx).file().map(|file| file.worktree_id(cx))
         {
-            if self
-                .active_buffer
-                .as_ref()
-                .is_some_and(|(old_worktree_id, old_buffer, _)| {
-                    (old_worktree_id, old_buffer.entity_id()) == (&worktree_id, buffer.entity_id())
-                })
-            {
-                return;
-            }
-
             let subscription = cx.subscribe_in(
                 &buffer,
                 window,