sidebar: Fix double borrow on startup (#52834)

Bennet Bo Fenner created

```
thread 'main' (35618165) panicked at crates/gpui/src/app/entity_map.rs:164:32:
cannot read workspace::multi_workspace::MultiWorkspace while it is already being updated
stack backtrace:
   0: __rustc::rust_begin_unwind
             at /rustc/e408947bfd200af42db322daf0fadfe7e26d3bd1/library/std/src/panicking.rs:689:5
   1: core::panicking::panic_fmt
             at /rustc/e408947bfd200af42db322daf0fadfe7e26d3bd1/library/core/src/panicking.rs:80:14
   2: gpui::app::entity_map::double_lease_panic::<workspace::multi_workspace::MultiWorkspace>
             at ./crates/gpui/src/app/entity_map.rs:208:5
   3: <gpui::app::entity_map::EntityMap>::read::<workspace::multi_workspace::MultiWorkspace>::{closure#1}
             at ./crates/gpui/src/app/entity_map.rs:164:32
   4: <core::option::Option<&workspace::multi_workspace::MultiWorkspace>>::unwrap_or_else::<<gpui::app::entity_map::EntityMap>::read<workspace::multi_workspace::MultiWorkspace>::{closure#1}>
             at /Users/bebo/.rustup/toolchains/1.94.1-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/option.rs:1067:21
   5: <gpui::app::entity_map::EntityMap>::read::<workspace::multi_workspace::MultiWorkspace>
             at ./crates/gpui/src/app/entity_map.rs:164:14
   6: <gpui::app::entity_map::Entity<workspace::multi_workspace::MultiWorkspace>>::read
             at ./crates/gpui/src/app/entity_map.rs:465:21
   7: <sidebar::Sidebar>::show_archive::{closure#0}
             at ./crates/sidebar/src/sidebar.rs:3462:15
   8: <core::option::Option<gpui::app::entity_map::Entity<workspace::multi_workspace::MultiWorkspace>>>::and_then::<gpui::app::entity_map::Entity<workspace::Workspace>, <sidebar::Sidebar>::show_archive::{closure#0}>
             at /Users/bebo/.rustup/toolchains/1.94.1-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/option.rs:1546:24
   9: <sidebar::Sidebar>::show_archive
             at ./crates/sidebar/src/sidebar.rs:3461:69
  10: <sidebar::Sidebar as workspace::multi_workspace::Sidebar>::restore_serialized_state
             at ./crates/sidebar/src/sidebar.rs:3606:22
  11: <gpui::app::entity_map::Entity<sidebar::Sidebar> as workspace::multi_workspace::SidebarHandle>::restore_serialized_state::{closure#0}
             at ./crates/workspace/src/multi_workspace.rs:216:18
  12: <gpui::app::App as gpui::AppContext>::update_entity::<sidebar::Sidebar, (), <gpui::app::entity_map::Entity<sidebar::Sidebar> as workspace::multi_workspace::SidebarHandle>::restore_serialized_state::{closure#0}>::{closure#0}
             at ./crates/gpui/src/app.rs:2397:26
  13: <gpui::app::App>::update::<(), <gpui::app::App as gpui::AppContext>::update_entity<sidebar::Sidebar, (), <gpui::app::entity_map::Entity<sidebar::Sidebar> as workspace::multi_workspace::SidebarHandle>::restore_serialized_state::{closure#0}>::{closure#0}>
             at ./crates/gpui/src/app.rs:886:22
  14: <gpui::app::App as gpui::AppContext>::update_entity::<sidebar::Sidebar, (), <gpui::app::entity_map::Entity<sidebar::Sidebar> as workspace::multi_workspace::SidebarHandle>::restore_serialized_state::{closure#0}>
             at ./crates/gpui/src/app.rs:2395:14
  15: <gpui::app::entity_map::Entity<sidebar::Sidebar>>::update::<(), gpui::app::App, <gpui::app::entity_map::Entity<sidebar::Sidebar> as workspace::multi_workspace::SidebarHandle>::restore_serialized_state::{closure#0}>
             at ./crates/gpui/src/app/entity_map.rs:481:12
  16: <gpui::app::entity_map::Entity<sidebar::Sidebar> as workspace::multi_workspace::SidebarHandle>::restore_serialized_state
             at ./crates/workspace/src/multi_workspace.rs:215:14
  17: workspace::restore_multiworkspace::{closure#0}::{closure#7}
             at ./crates/workspace/src/workspace.rs:8712:29
  18: <gpui::window::WindowHandle<workspace::multi_workspace::MultiWorkspace>>::update::<gpui::app::async_context::AsyncApp, (), workspace::restore_multiworkspace::{closure#0}::{closure#7}>::{closure#0}::{closure#1}
             at ./crates/gpui/src/window.rs:5318:43
  19: <gpui::app::App as gpui::AppContext>::update_entity::<workspace::multi_workspace::MultiWorkspace, (), <gpui::window::WindowHandle<workspace::multi_workspace::MultiWorkspace>>::update<gpui::app::async_context::AsyncApp, (), workspace::restore_multiworkspace::{closure#0}::{closure#7}>::{closure#0}::{closure#1}>::{closure#0}
             at ./crates/gpui/src/app.rs:2397:26
  20: <gpui::app::App>::update::<(), <gpui::app::App as gpui::AppContext>::update_entity<workspace::multi_workspace::MultiWorkspace, (), <gpui::window::WindowHandle<workspace::multi_workspace::MultiWorkspace>>::update<gpui::app::async_context::AsyncApp, (), workspace::restore_multiworkspace::{closure#0}::{closure#7}>::{closure#0}::{closure#1}>::{closure#0}>
             at ./crates/gpui/src/app.rs:886:22
  21: <gpui::app::App as gpui::AppContext>::update_entity::<workspace::multi_workspace::MultiWorkspace, (), <gpui::window::WindowHandle<workspace::multi_workspace::MultiWorkspace>>::update<gpui::app::async_context::AsyncApp, (), workspace::restore_multiworkspace::{closure#0}::{closure#7}>::{closure#0}::{closure#1}>
             at ./crates/gpui/src/app.rs:2395:14
  22: <gpui::app::entity_map::Entity<workspace::multi_workspace::MultiWorkspace>>::update::<(), gpui::app::App, <gpui::window::WindowHandle<workspace::multi_workspace::MultiWorkspace>>::update<gpui::app::async_context::AsyncApp, (), workspace::restore_multiworkspace::{closure#0}::{closure#7}>::{closure#0}::{closure#1}>
             at ./crates/gpui/src/app/entity_map.rs:481:12
  23: <gpui::window::WindowHandle<workspace::multi_workspace::MultiWorkspace>>::update::<gpui::app::async_context::AsyncApp, (), workspace::restore_multiworkspace::{closure#0}::{closure#7}>::{closure#0}
             at ./crates/gpui/src/window.rs:5318:21
  24: <gpui::app::App>::update_window_id::<core::result::Result<(), anyhow::Error>, <gpui::window::WindowHandle<workspace::multi_workspace::MultiWorkspace>>::update<gpui::app::async_context::AsyncApp, (), workspace::restore_multiworkspace::{closure#0}::{closure#7}>::{closure#0}>::{closure#0}
             at ./crates/gpui/src/app.rs:1561:26
  25: <gpui::app::App>::update::<core::option::Option<core::result::Result<(), anyhow::Error>>, <gpui::app::App>::update_window_id<core::result::Result<(), anyhow::Error>, <gpui::window::WindowHandle<workspace::multi_workspace::MultiWorkspace>>::update<gpui::app::async_context::AsyncApp, (), workspace::restore_multiworkspace::{closure#0}::{closure#7}>::{closure#0}>::{closure#0}>
             at ./crates/gpui/src/app.rs:886:22
  26: <gpui::app::App>::update_window_id::<core::result::Result<(), anyhow::Error>, <gpui::window::WindowHandle<workspace::multi_workspace::MultiWorkspace>>::update<gpui::app::async_context::AsyncApp, (), workspace::restore_multiworkspace::{closure#0}::{closure#7}>::{closure#0}>
             at ./crates/gpui/src/app.rs:1555:14
  27: <gpui::app::App as gpui::AppContext>::update_window::<core::result::Result<(), anyhow::Error>, <gpui::window::WindowHandle<workspace::multi_workspace::MultiWorkspace>>::update<gpui::app::async_context::AsyncApp, (), workspace::restore_multiworkspace::{closure#0}::{closure#7}>::{closure#0}>
             at ./crates/gpui/src/app.rs:2425:14
  28: <gpui::app::async_context::AsyncApp as gpui::AppContext>::update_window::<core::result::Result<(), anyhow::Error>, <gpui::window::WindowHandle<workspace::multi_workspace::MultiWorkspace>>::update<gpui::app::async_context::AsyncApp, (), workspace::restore_multiworkspace::{closure#0}::{closure#7}>::{closure#0}>
             at ./crates/gpui/src/app/async_context.rs:94:14
  29: <gpui::window::WindowHandle<workspace::multi_workspace::MultiWorkspace>>::update::<gpui::app::async_context::AsyncApp, (), workspace::restore_multiworkspace::{closure#0}::{closure#7}>
             at ./crates/gpui/src/window.rs:5313:12
  30: workspace::restore_multiworkspace::{closure#0}
             at ./crates/workspace/src/workspace.rs:8710:14
  31: zed::restore_or_create_workspace::{closure#0}
             at ./crates/zed/src/main.rs:1358:82
  32: zed::main::{closure#10}::{closure#16}::{closure#0}::<i32>
             at ./crates/zed/src/main.rs:877:84
  33: <gpui::app::App>::spawn::<zed::main::{closure#10}::{closure#16}, ()>::{closure#0}
             at ./crates/gpui/src/app.rs:1633:44
  34: <core::pin::Pin<alloc::boxed::Box<dyn core::future::future::Future<Output = ()>>> as core::future::future::Future>::poll
             at /Users/bebo/.rustup/toolchains/1.94.1-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/future/future.rs:133:9
  35: <core::pin::Pin<alloc::boxed::Box<dyn core::future::future::Future<Output = ()>>> as core::future::future::Future>::poll
             at /Users/bebo/.rustup/toolchains/1.94.1-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/future/future.rs:133:9
  36: <scheduler::executor::spawn_local_with_source_location::Checked<core::pin::Pin<alloc::boxed::Box<dyn core::future::future::Future<Output = ()>>>> as core::future::future::Future>::poll
             at ./crates/scheduler/src/executor.rs:361:64
  37: <async_task::raw::RawTask<scheduler::executor::spawn_local_with_source_location::Checked<core::pin::Pin<alloc::boxed::Box<dyn core::future::future::Future<Output = ()>>>>, (), <scheduler::executor::ForegroundExecutor>::spawn<core::pin::Pin<alloc::boxed::Box<dyn core::future::future::Future<Output = ()>>>>::{closure#0}, scheduler::RunnableMeta>>::run
             at /Users/bebo/.cargo/git/checkouts/async-task-e468f817236eac43/b4486cd/src/raw.rs:296:17
  38: <async_task::runnable::Runnable<scheduler::RunnableMeta>>::run
             at /Users/bebo/.cargo/git/checkouts/async-task-e468f817236eac43/b4486cd/src/runnable.rs:788:18
  39: gpui_macos::dispatcher::trampoline
             at ./crates/gpui_macos/src/dispatcher.rs:197:14
  40: <unknown>
  41: <unknown>
  42: <unknown>
  43: <unknown>
  44: <unknown>
  45: <unknown>
  46: <unknown>
  47: <unknown>
  48: <unknown>
  49: <unknown>
  50: <unknown>
  51: <unknown>
  52: <unknown>
  53: <() as objc::message::MessageArguments>::invoke::<()>
             at /Users/bebo/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/objc-0.2.7/src/message/mod.rs:128:17
  54: objc::message::platform::send_unverified::<objc::runtime::Object, (), ()>
             at /Users/bebo/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/objc-0.2.7/src/message/apple/mod.rs:27:9
  55: objc::message::send_message::<objc::runtime::Object, (), ()>
             at /Users/bebo/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/objc-0.2.7/src/message/mod.rs:178:5
  56: <*mut objc::runtime::Object as cocoa::appkit::NSApplication>::run
             at /Users/bebo/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/cocoa-0.26.0/src/appkit.rs:628:9
  57: <gpui_macos::platform::MacPlatform as gpui::platform::Platform>::run
             at ./crates/gpui_macos/src/platform.rs:488:17
  58: <gpui::app::Application>::run::<zed::main::{closure#10}>
             at ./crates/gpui/src/app.rs:187:18
  59: zed::main
             at ./crates/zed/src/main.rs:456:9
  60: <fn() as core::ops::function::FnOnce<()>>::call_once
             at /Users/bebo/.rustup/toolchains/1.94.1-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/function.rs:250:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace
```

Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Release Notes:

- N/A

Change summary

crates/sidebar/src/sidebar.rs       |  4 ++
crates/sidebar/src/sidebar_tests.rs | 35 ++++++++++++++++++++++++++++++
2 files changed, 38 insertions(+), 1 deletion(-)

Detailed changes

crates/sidebar/src/sidebar.rs 🔗

@@ -3601,7 +3601,9 @@ impl WorkspaceSidebar for Sidebar {
                 .map(|(s, count)| (PathList::deserialize(&s), count))
                 .collect();
             if serialized.active_view == SerializedSidebarView::Archive {
-                self.show_archive(window, cx);
+                cx.defer_in(window, |this, window, cx| {
+                    this.show_archive(window, cx);
+                });
             }
         }
         cx.notify();

crates/sidebar/src/sidebar_tests.rs 🔗

@@ -322,6 +322,41 @@ async fn test_serialization_round_trip(cx: &mut TestAppContext) {
     assert_eq!(expanded1.get(&path_list), Some(&2));
 }
 
+#[gpui::test]
+async fn test_restore_serialized_archive_view_does_not_panic(cx: &mut TestAppContext) {
+    // A regression test to ensure that restoring a serialized archive view does not panic.
+    let project = init_test_project_with_agent_panel("/my-project", cx).await;
+    let (multi_workspace, cx) =
+        cx.add_window_view(|window, cx| MultiWorkspace::test_new(project.clone(), window, cx));
+    let (sidebar, _panel) = setup_sidebar_with_agent_panel(&multi_workspace, cx);
+    cx.update(|_window, cx| {
+        AgentRegistryStore::init_test_global(cx, vec![]);
+    });
+
+    let serialized = serde_json::to_string(&SerializedSidebar {
+        width: Some(400.0),
+        collapsed_groups: Vec::new(),
+        expanded_groups: Vec::new(),
+        active_view: SerializedSidebarView::Archive,
+    })
+    .expect("serialization should succeed");
+
+    multi_workspace.update_in(cx, |multi_workspace, window, cx| {
+        if let Some(sidebar) = multi_workspace.sidebar() {
+            sidebar.restore_serialized_state(&serialized, window, cx);
+        }
+    });
+    cx.run_until_parked();
+
+    // After the deferred `show_archive` runs, the view should be Archive.
+    sidebar.read_with(cx, |sidebar, _cx| {
+        assert!(
+            matches!(sidebar.view, SidebarView::Archive(_)),
+            "expected sidebar view to be Archive after restore, got ThreadList"
+        );
+    });
+}
+
 #[test]
 fn test_clean_mention_links() {
     // Simple mention link