debugger: Show errors loading stack (#32658)

- **TEMP**
- **Show errors loading stack frames**
- **Stop cloning every DAP response unnecessarily**

Closes #ISSUE

Release Notes:

- debugger: Show errors loading stack frames.

<img width="1840" alt="Screenshot 2025-06-12 at 23 53 42"
src="https://github.com/user-attachments/assets/310d3046-f34c-4964-acef-f9742441c9db"
/>

crates/debugger_ui/src/session/running/stack_frame_list.rs

@@ -36,6 +36,7 @@ pub struct StackFrameList {
     opened_stack_frame_id: Option<StackFrameId>,
     scrollbar_state: ScrollbarState,
     list_state: ListState,
+    error: Option<SharedString>,
     _refresh_task: Task<()>,
 }
 
@@ -82,6 +83,7 @@ impl StackFrameList {
             state,
             _subscription,
             entries: Default::default(),
+            error: None,
             selected_ix: None,
             opened_stack_frame_id: None,
             list_state,
@@ -113,21 +115,19 @@ impl StackFrameList {
             .collect::<Vec<_>>()
     }
 
-    fn stack_frames(&self, cx: &mut App) -> Vec<StackFrame> {
+    fn stack_frames(&self, cx: &mut App) -> Result<Vec<StackFrame>> {
-        self.state
+        if let Ok(Some(thread_id)) = self.state.read_with(cx, |state, _| state.thread_id) {
-            .read_with(cx, |state, _| state.thread_id)
-            .ok()
-            .flatten()
-            .map(|thread_id| {
             self.session
                 .update(cx, |this, cx| this.stack_frames(thread_id, cx))
-            })
+        } else {
-            .unwrap_or_default()
+            Ok(Vec::default())
+        }
     }
 
     #[cfg(test)]
     pub(crate) fn dap_stack_frames(&self, cx: &mut App) -> Vec<dap::StackFrame> {
         self.stack_frames(cx)
+            .unwrap_or_default()
             .into_iter()
             .map(|stack_frame| stack_frame.dap.clone())
             .collect()
@@ -149,7 +149,7 @@ impl StackFrameList {
             let debounce = this
                 .update(cx, |this, cx| {
                     let new_stack_frames = this.stack_frames(cx);
-                    new_stack_frames.is_empty() && !this.entries.is_empty()
+                    new_stack_frames.unwrap_or_default().is_empty() && !this.entries.is_empty()
                 })
                 .ok()
                 .unwrap_or_default();
@@ -185,7 +185,18 @@ impl StackFrameList {
         let mut first_stack_frame = None;
         let mut first_not_subtle_frame = None;
 
-        let stack_frames = self.stack_frames(cx);
+        let stack_frames = match self.stack_frames(cx) {
+            Ok(stack_frames) => stack_frames,
+            Err(e) => {
+                self.error = Some(format!("{}", e).into());
+                self.entries.clear();
+                self.selected_ix = None;
+                self.list_state.reset(0);
+                cx.emit(StackFrameListEvent::BuiltEntries);
+                cx.notify();
+                return;
+            }
+        };
         for stack_frame in &stack_frames {
             match stack_frame.dap.presentation_hint {
                 Some(dap::StackFramePresentationHint::Deemphasize) => {
@@ -212,8 +223,7 @@ impl StackFrameList {
         if !collapsed_entries.is_empty() {
             entries.push(StackFrameEntry::Collapsed(collapsed_entries.clone()));
         }
-
+        self.entries = entries;
-        std::mem::swap(&mut self.entries, &mut entries);
 
         if let Some(ix) = first_not_subtle_frame
             .or(first_stack_frame)
@@ -657,7 +667,7 @@ impl StackFrameList {
     }
 
     fn render_list(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
-        list(self.list_state.clone()).size_full()
+        div().p_1().child(list(self.list_state.clone()).size_full())
     }
 }
 
@@ -666,12 +676,27 @@ impl Render for StackFrameList {
         div()
             .track_focus(&self.focus_handle)
             .size_full()
-            .p_1()
             .on_action(cx.listener(Self::select_next))
             .on_action(cx.listener(Self::select_previous))
             .on_action(cx.listener(Self::select_first))
             .on_action(cx.listener(Self::select_last))
             .on_action(cx.listener(Self::confirm))
+            .when_some(self.error.clone(), |el, error| {
+                el.child(
+                    h_flex()
+                        .bg(cx.theme().status().warning_background)
+                        .border_b_1()
+                        .border_color(cx.theme().status().warning_border)
+                        .pl_1()
+                        .child(Icon::new(IconName::Warning).color(Color::Warning))
+                        .gap_2()
+                        .child(
+                            Label::new(error)
+                                .size(LabelSize::Small)
+                                .color(Color::Warning),
+                        ),
+                )
+            })
             .child(self.render_list(window, cx))
             .child(self.render_vertical_scrollbar(cx))
     }

crates/project/src/debugger/session.rs

@@ -36,6 +36,7 @@ use gpui::{
     Task, WeakEntity,
 };
 
+use rpc::ErrorExt;
 use serde_json::Value;
 use smol::stream::StreamExt;
 use std::any::TypeId;
@@ -108,6 +109,7 @@ impl ThreadStatus {
 pub struct Thread {
     dap: dap::Thread,
     stack_frames: Vec<StackFrame>,
+    stack_frames_error: Option<anyhow::Error>,
     _has_stopped: bool,
 }
 
@@ -116,6 +118,7 @@ impl From<dap::Thread> for Thread {
         Self {
             dap,
             stack_frames: Default::default(),
+            stack_frames_error: None,
             _has_stopped: false,
         }
     }
@@ -1388,12 +1391,7 @@ impl Session {
     fn fetch<T: DapCommand + PartialEq + Eq + Hash>(
         &mut self,
         request: T,
-        process_result: impl FnOnce(
+        process_result: impl FnOnce(&mut Self, Result<T::Response>, &mut Context<Self>) + 'static,
-            &mut Self,
-            Result<T::Response>,
-            &mut Context<Self>,
-        ) -> Option<T::Response>
-        + 'static,
         cx: &mut Context<Self>,
     ) {
         const {
@@ -1422,7 +1420,10 @@ impl Session {
                 &self.capabilities,
                 &self.mode,
                 command,
-                process_result,
+                |this, result, cx| {
+                    process_result(this, result, cx);
+                    None
+                },
                 cx,
             );
             let task = cx
@@ -1438,17 +1439,6 @@ impl Session {
         }
     }
 
-    pub async fn request2<T: DapCommand + PartialEq + Eq + Hash>(
-        &self,
-        request: T,
-    ) -> Result<T::Response> {
-        if !T::is_supported(&self.capabilities) {
-            anyhow::bail!("DAP request {:?} is not supported", request);
-        }
-
-        self.mode.request_dap(request).await
-    }
-
     fn request_inner<T: DapCommand + PartialEq + Eq + Hash>(
         capabilities: &Capabilities,
         mode: &Mode,
@@ -1535,18 +1525,18 @@ impl Session {
         self.fetch(
             dap_command::ThreadsCommand,
             |this, result, cx| {
-                let result = result.log_err()?;
+                let Some(result) = result.log_err() else {
+                    return;
+                };
 
                 this.threads = result
-                    .iter()
+                    .into_iter()
                     .map(|thread| (ThreadId(thread.id), Thread::from(thread.clone())))
                     .collect();
 
                 this.invalidate_command_type::<StackTraceCommand>();
                 cx.emit(SessionEvent::Threads);
                 cx.notify();
-
-                Some(result)
             },
             cx,
         );
@@ -1566,13 +1556,13 @@ impl Session {
         self.fetch(
             dap_command::ModulesCommand,
             |this, result, cx| {
-                let result = result.log_err()?;
+                let Some(result) = result.log_err() else {
+                    return;
+                };
 
-                this.modules = result.iter().cloned().collect();
+                this.modules = result;
                 cx.emit(SessionEvent::Modules);
                 cx.notify();
-
-                Some(result)
             },
             cx,
         );
@@ -1651,11 +1641,12 @@ impl Session {
         self.fetch(
             dap_command::LoadedSourcesCommand,
             |this, result, cx| {
-                let result = result.log_err()?;
+                let Some(result) = result.log_err() else {
-                this.loaded_sources = result.iter().cloned().collect();
+                    return;
+                };
+                this.loaded_sources = result;
                 cx.emit(SessionEvent::LoadedSources);
                 cx.notify();
-                Some(result)
             },
             cx,
         );
@@ -1961,7 +1952,11 @@ impl Session {
         .detach();
     }
 
-    pub fn stack_frames(&mut self, thread_id: ThreadId, cx: &mut Context<Self>) -> Vec<StackFrame> {
+    pub fn stack_frames(
+        &mut self,
+        thread_id: ThreadId,
+        cx: &mut Context<Self>,
+    ) -> Result<Vec<StackFrame>> {
         if self.thread_states.thread_status(thread_id) == ThreadStatus::Stopped
             && self.requests.contains_key(&ThreadsCommand.type_id())
             && self.threads.contains_key(&thread_id)
@@ -1977,20 +1972,31 @@ impl Session {
                     levels: None,
                 },
                 move |this, stack_frames, cx| {
-                    let stack_frames = stack_frames.log_err()?;
+                    let entry =
-
+                        this.threads
-                    let entry = this.threads.entry(thread_id).and_modify(|thread| {
+                            .entry(thread_id)
-                        thread.stack_frames =
+                            .and_modify(|thread| match &stack_frames {
-                            stack_frames.iter().cloned().map(StackFrame::from).collect();
+                                Ok(stack_frames) => {
+                                    thread.stack_frames = stack_frames
+                                        .iter()
+                                        .cloned()
+                                        .map(StackFrame::from)
+                                        .collect();
+                                    thread.stack_frames_error = None;
+                                }
+                                Err(error) => {
+                                    thread.stack_frames.clear();
+                                    thread.stack_frames_error = Some(error.cloned());
+                                }
                             });
                     debug_assert!(
                         matches!(entry, indexmap::map::Entry::Occupied(_)),
                         "Sent request for thread_id that doesn't exist"
                     );
-
+                    if let Ok(stack_frames) = stack_frames {
                         this.stack_frames.extend(
                             stack_frames
-                            .iter()
+                                .into_iter()
                                 .filter(|frame| {
                                     // Workaround for JavaScript debug adapter sending out "fake" stack frames for delineating await points. This is fine,
                                     // except that they always use an id of 0 for it, which collides with other (valid) stack frames.
@@ -2000,25 +2006,29 @@ impl Session {
                                         && frame.presentation_hint
                                             == Some(StackFramePresentationHint::Label))
                                 })
-                            .cloned()
                                 .map(|frame| (frame.id, StackFrame::from(frame))),
                         );
+                    }
 
                     this.invalidate_command_type::<ScopesCommand>();
                     this.invalidate_command_type::<VariablesCommand>();
 
                     cx.emit(SessionEvent::StackTrace);
-                    cx.notify();
-                    Some(stack_frames)
                 },
                 cx,
             );
         }
 
-        self.threads
+        match self.threads.get(&thread_id) {
-            .get(&thread_id)
+            Some(thread) => {
-            .map(|thread| thread.stack_frames.clone())
+                if let Some(error) = &thread.stack_frames_error {
-            .unwrap_or_default()
+                    Err(error.cloned())
+                } else {
+                    Ok(thread.stack_frames.clone())
+                }
+            }
+            None => Ok(Vec::new()),
+        }
     }
 
     pub fn scopes(&mut self, stack_frame_id: u64, cx: &mut Context<Self>) -> &[dap::Scope] {
@@ -2030,9 +2040,11 @@ impl Session {
             self.fetch(
                 ScopesCommand { stack_frame_id },
                 move |this, scopes, cx| {
-                    let scopes = scopes.log_err()?;
+                    let Some(scopes) = scopes.log_err() else {
+                        return
+                    };
 
-                    for scope in scopes .iter(){
+                    for scope in scopes.iter() {
                         this.variables(scope.variables_reference, cx);
                     }
 
@@ -2040,7 +2052,7 @@ impl Session {
                         .stack_frames
                         .entry(stack_frame_id)
                         .and_modify(|stack_frame| {
-                            stack_frame.scopes = scopes.clone();
+                            stack_frame.scopes = scopes;
                         });
 
                     cx.emit(SessionEvent::Variables);
@@ -2049,8 +2061,6 @@ impl Session {
                         matches!(entry, indexmap::map::Entry::Occupied(_)),
                         "Sent scopes request for stack_frame_id that doesn't exist or hasn't been fetched"
                     );
-
-                    Some(scopes)
                 },
                 cx,
             );
@@ -2092,13 +2102,14 @@ impl Session {
         self.fetch(
             command,
             move |this, variables, cx| {
-                let variables = variables.log_err()?;
+                let Some(variables) = variables.log_err() else {
-                this.variables
+                    return;
-                    .insert(variables_reference, variables.clone());
+                };
+
+                this.variables.insert(variables_reference, variables);
 
                 cx.emit(SessionEvent::Variables);
                 cx.emit(SessionEvent::InvalidateInlineValue);
-                Some(variables)
             },
             cx,
         );
@@ -2209,9 +2220,10 @@ impl Session {
         self.fetch(
             LocationsCommand { reference },
             move |this, response, _| {
-                let response = response.log_err()?;
+                let Some(response) = response.log_err() else {
-                this.locations.insert(reference, response.clone());
+                    return;
-                Some(response)
+                };
+                this.locations.insert(reference, response);
             },
             cx,
         );