Fix progress token is already registered crash

After we started reporting progress when running cargo check during
loading, it is possible to crash the client with two identical progress
tokens.

This points to a deeper issue: we might be running several cargo checks
concurrently, which doesn't make sense.

This commit linearizes all workspace fetches, making sure no updates are
lost.

As an additional touch, it also normalizes progress & result reporting,
to make sure they stand in sync.

1 files changed, 18 insertions, 6 deletions

diff --git a/crates/rust-analyzer/src/reload.rs b/crates/rust-analyzer/src/reload.rs
index f4e084741..accf2ef8c 100644
--- a/crates/rust-analyzer/src/reload.rs
+++ b/crates/rust-analyzer/src/reload.rs
@@ -19,7 +19,7 @@ use lsp_ext::StatusParams;
 pub(crate) enum ProjectWorkspaceProgress {
     Begin,
     Report(String),
-    End,
+    End(Vec<anyhow::Result<ProjectWorkspace>>),
 }
 
 impl GlobalState {
@@ -30,7 +30,7 @@ impl GlobalState {
             self.analysis_host.update_lru_capacity(self.config.lru_capacity());
         }
         if self.config.linked_projects() != old_config.linked_projects() {
-            self.fetch_workspaces()
+            self.fetch_workspaces_request()
         } else if self.config.flycheck() != old_config.flycheck() {
             self.reload_flycheck();
         }
@@ -44,7 +44,7 @@ impl GlobalState {
             Status::Ready | Status::Invalid => (),
         }
         if self.config.cargo_autoreload() {
-            self.fetch_workspaces();
+            self.fetch_workspaces_request();
         } else {
             self.transition(Status::NeedsReload);
         }
@@ -98,8 +98,15 @@ impl GlobalState {
             });
         }
     }
-    pub(crate) fn fetch_workspaces(&mut self) {
+
+    pub(crate) fn fetch_workspaces_request(&mut self) {
+        self.fetch_workspaces_queue.request_op()
+    }
+    pub(crate) fn fetch_workspaces_if_needed(&mut self) {
         log::info!("will fetch workspaces");
+        if !self.fetch_workspaces_queue.should_start_op() {
+            return;
+        }
 
         self.task_pool.handle.spawn_with_sender({
             let linked_projects = self.config.linked_projects();
@@ -133,12 +140,17 @@ impl GlobalState {
                     })
                     .collect::<Vec<_>>();
 
-                sender.send(Task::FetchWorkspace(ProjectWorkspaceProgress::End)).unwrap();
                 log::info!("did fetch workspaces {:?}", workspaces);
-                sender.send(Task::Workspaces(workspaces)).unwrap()
+                sender
+                    .send(Task::FetchWorkspace(ProjectWorkspaceProgress::End(workspaces)))
+                    .unwrap();
             }
         });
     }
+    pub(crate) fn fetch_workspaces_completed(&mut self) {
+        self.fetch_workspaces_queue.op_completed()
+    }
+
     pub(crate) fn switch_workspaces(&mut self, workspaces: Vec<anyhow::Result<ProjectWorkspace>>) {
         let _p = profile::span("GlobalState::switch_workspaces");
         log::info!("will switch workspaces: {:?}", workspaces);