Fix attach modal showing local processes in SSH sessions (#37608)

Closes #37520

This change makes the attach modal load processes from the remote server
when connecting via SSH, rather than showing local processes from the
client machine.

This works by using the new GetProcessesRequest RPC message to allow
downstream clients to get the correct processes to display. It also only
works with downstream ssh clients because the message handler is only
registered on headless projects.

Release Notes:

- debugger: Fix bug where SSH attach modal showed local processes
instead of processes from the server

crates/debugger_ui/src/attach_modal.rs

@@ -1,8 +1,10 @@
 use dap::{DapRegistry, DebugRequest};
 use fuzzy::{StringMatch, StringMatchCandidate};
-use gpui::{AppContext, DismissEvent, Entity, EventEmitter, Focusable, Render};
+use gpui::{AppContext, DismissEvent, Entity, EventEmitter, Focusable, Render, Task};
 use gpui::{Subscription, WeakEntity};
 use picker::{Picker, PickerDelegate};
+use project::Project;
+use rpc::proto;
 use task::ZedDebugConfig;
 use util::debug_panic;
 
@@ -56,29 +58,28 @@ impl AttachModal {
     pub fn new(
         definition: ZedDebugConfig,
         workspace: WeakEntity<Workspace>,
+        project: Entity<Project>,
         modal: bool,
         window: &mut Window,
         cx: &mut Context<Self>,
     ) -> Self {
-        let mut processes: Box<[_]> = System::new_all()
-            .processes()
-            .values()
-            .map(|process| {
-                let name = process.name().to_string_lossy().into_owned();
-                Candidate {
-                    name: name.into(),
-                    pid: process.pid().as_u32(),
-                    command: process
-                        .cmd()
-                        .iter()
-                        .map(|s| s.to_string_lossy().to_string())
-                        .collect::<Vec<_>>(),
-                }
-            })
-            .collect();
-        processes.sort_by_key(|k| k.name.clone());
-        let processes = processes.into_iter().collect();
-        Self::with_processes(workspace, definition, processes, modal, window, cx)
+        let processes_task = get_processes_for_project(&project, cx);
+
+        let modal = Self::with_processes(workspace, definition, Arc::new([]), modal, window, cx);
+
+        cx.spawn_in(window, async move |this, cx| {
+            let processes = processes_task.await;
+            this.update_in(cx, |modal, window, cx| {
+                modal.picker.update(cx, |picker, cx| {
+                    picker.delegate.candidates = processes;
+                    picker.refresh(window, cx);
+                });
+            })?;
+            anyhow::Ok(())
+        })
+        .detach_and_log_err(cx);
+
+        modal
     }
 
     pub(super) fn with_processes(
@@ -332,6 +333,57 @@ impl PickerDelegate for AttachModalDelegate {
     }
 }
 
+fn get_processes_for_project(project: &Entity<Project>, cx: &mut App) -> Task<Arc<[Candidate]>> {
+    let project = project.read(cx);
+
+    if let Some(remote_client) = project.remote_client() {
+        let proto_client = remote_client.read(cx).proto_client();
+        cx.spawn(async move |_cx| {
+            let response = proto_client
+                .request(proto::GetProcesses {
+                    project_id: proto::REMOTE_SERVER_PROJECT_ID,
+                })
+                .await
+                .unwrap_or_else(|_| proto::GetProcessesResponse {
+                    processes: Vec::new(),
+                });
+
+            let mut processes: Vec<Candidate> = response
+                .processes
+                .into_iter()
+                .map(|p| Candidate {
+                    pid: p.pid,
+                    name: p.name.into(),
+                    command: p.command,
+                })
+                .collect();
+
+            processes.sort_by_key(|k| k.name.clone());
+            Arc::from(processes.into_boxed_slice())
+        })
+    } else {
+        let mut processes: Box<[_]> = System::new_all()
+            .processes()
+            .values()
+            .map(|process| {
+                let name = process.name().to_string_lossy().into_owned();
+                Candidate {
+                    name: name.into(),
+                    pid: process.pid().as_u32(),
+                    command: process
+                        .cmd()
+                        .iter()
+                        .map(|s| s.to_string_lossy().to_string())
+                        .collect::<Vec<_>>(),
+                }
+            })
+            .collect();
+        processes.sort_by_key(|k| k.name.clone());
+        let processes = processes.into_iter().collect();
+        Task::ready(processes)
+    }
+}
+
 #[cfg(any(test, feature = "test-support"))]
 pub(crate) fn _process_names(modal: &AttachModal, cx: &mut Context<AttachModal>) -> Vec<String> {
     modal.picker.read_with(cx, |picker, _| {