fix: Fix completions disappearing when typing two keys in quick succession

crates/rust-analyzer/src/dispatch.rs

@@ -1,12 +1,12 @@
 //! See [RequestDispatcher].
 use std::{fmt, panic, thread};
 
+use ide::Cancelled;
 use lsp_server::ExtractError;
 use serde::{de::DeserializeOwned, Serialize};
 
 use crate::{
     global_state::{GlobalState, GlobalStateSnapshot},
-    lsp_utils::is_cancelled,
     main_loop::Task,
     LspError, Result,
 };
@@ -37,38 +37,41 @@ impl<'a> RequestDispatcher<'a> {
     pub(crate) fn on_sync_mut<R>(
         &mut self,
         f: fn(&mut GlobalState, R::Params) -> Result<R::Result>,
-    ) -> Result<&mut Self>
+    ) -> &mut Self
     where
         R: lsp_types::request::Request,
         R::Params: DeserializeOwned + panic::UnwindSafe + fmt::Debug,
         R::Result: Serialize,
     {
-        let (id, params, panic_context) = match self.parse::<R>() {
+        let (req, params, panic_context) = match self.parse::<R>() {
             Some(it) => it,
-            None => return Ok(self),
+            None => return self,
+        };
+        let result = {
+            let _pctx = stdx::panic_context::enter(panic_context);
+            f(self.global_state, params)
+        };
+        match result_to_response::<R>(req.id.clone(), result) {
+            Ok(response) => self.global_state.respond(response),
+            Err(_) => self.global_state.task_pool.handle.send_retry(req),
         };
-        let _pctx = stdx::panic_context::enter(panic_context);
 
-        let result = f(self.global_state, params);
-        let response = result_to_response::<R>(id, result);
-
-        self.global_state.respond(response);
-        Ok(self)
+        self
     }
 
     /// Dispatches the request onto the current thread.
     pub(crate) fn on_sync<R>(
         &mut self,
         f: fn(GlobalStateSnapshot, R::Params) -> Result<R::Result>,
-    ) -> Result<&mut Self>
+    ) -> &mut Self
     where
-        R: lsp_types::request::Request + 'static,
+        R: lsp_types::request::Request,
         R::Params: DeserializeOwned + panic::UnwindSafe + fmt::Debug,
         R::Result: Serialize,
     {
-        let (id, params, panic_context) = match self.parse::<R>() {
+        let (req, params, panic_context) = match self.parse::<R>() {
             Some(it) => it,
-            None => return Ok(self),
+            None => return self,
         };
         let global_state_snapshot = self.global_state.snapshot();
 
@@ -76,10 +79,13 @@ impl<'a> RequestDispatcher<'a> {
             let _pctx = stdx::panic_context::enter(panic_context);
             f(global_state_snapshot, params)
         });
-        let response = thread_result_to_response::<R>(id, result);
 
-        self.global_state.respond(response);
-        Ok(self)
+        match thread_result_to_response::<R>(req.id.clone(), result) {
+            Ok(response) => self.global_state.respond(response),
+            Err(_) => self.global_state.task_pool.handle.send_retry(req),
+        };
+
+        self
     }
 
     /// Dispatches the request onto thread pool
@@ -92,7 +98,7 @@ impl<'a> RequestDispatcher<'a> {
         R::Params: DeserializeOwned + panic::UnwindSafe + Send + fmt::Debug,
         R::Result: Serialize,
     {
-        let (id, params, panic_context) = match self.parse::<R>() {
+        let (req, params, panic_context) = match self.parse::<R>() {
             Some(it) => it,
             None => return self,
         };
@@ -104,8 +110,10 @@ impl<'a> RequestDispatcher<'a> {
                     let _pctx = stdx::panic_context::enter(panic_context);
                     f(world, params)
                 });
-                let response = thread_result_to_response::<R>(id, result);
-                Task::Response(response)
+                match thread_result_to_response::<R>(req.id.clone(), result) {
+                    Ok(response) => Task::Response(response),
+                    Err(_) => Task::Retry(req),
+                }
             }
         });
 
@@ -124,7 +132,7 @@ impl<'a> RequestDispatcher<'a> {
         }
     }
 
-    fn parse<R>(&mut self) -> Option<(lsp_server::RequestId, R::Params, String)>
+    fn parse<R>(&mut self) -> Option<(lsp_server::Request, R::Params, String)>
     where
         R: lsp_types::request::Request,
         R::Params: DeserializeOwned + fmt::Debug,
@@ -134,12 +142,12 @@ impl<'a> RequestDispatcher<'a> {
             _ => return None,
         };
 
-        let res = crate::from_json(R::METHOD, req.params);
+        let res = crate::from_json(R::METHOD, &req.params);
         match res {
             Ok(params) => {
                 let panic_context =
                     format!("\nversion: {}\nrequest: {} {:#?}", env!("REV"), R::METHOD, params);
-                Some((req.id, params, panic_context))
+                Some((req, params, panic_context))
             }
             Err(err) => {
                 let response = lsp_server::Response::new_err(
@@ -157,7 +165,7 @@ impl<'a> RequestDispatcher<'a> {
 fn thread_result_to_response<R>(
     id: lsp_server::RequestId,
     result: thread::Result<Result<R::Result>>,
-) -> lsp_server::Response
+) -> Result<lsp_server::Response, Cancelled>
 where
     R: lsp_types::request::Request,
     R::Params: DeserializeOwned,
@@ -166,19 +174,22 @@ where
     match result {
         Ok(result) => result_to_response::<R>(id, result),
         Err(panic) => {
-            let mut message = "request handler panicked".to_string();
-
             let panic_message = panic
                 .downcast_ref::<String>()
                 .map(String::as_str)
                 .or_else(|| panic.downcast_ref::<&str>().copied());
 
+            let mut message = "request handler panicked".to_string();
             if let Some(panic_message) = panic_message {
                 message.push_str(": ");
                 message.push_str(panic_message)
             };
 
-            lsp_server::Response::new_err(id, lsp_server::ErrorCode::InternalError as i32, message)
+            Ok(lsp_server::Response::new_err(
+                id,
+                lsp_server::ErrorCode::InternalError as i32,
+                message,
+            ))
         }
     }
 }
@@ -186,33 +197,27 @@ where
 fn result_to_response<R>(
     id: lsp_server::RequestId,
     result: Result<R::Result>,
-) -> lsp_server::Response
+) -> Result<lsp_server::Response, Cancelled>
 where
     R: lsp_types::request::Request,
     R::Params: DeserializeOwned,
     R::Result: Serialize,
 {
-    match result {
+    let res = match result {
         Ok(resp) => lsp_server::Response::new_ok(id, &resp),
         Err(e) => match e.downcast::<LspError>() {
             Ok(lsp_error) => lsp_server::Response::new_err(id, lsp_error.code, lsp_error.message),
-            Err(e) => {
-                if is_cancelled(&*e) {
-                    lsp_server::Response::new_err(
-                        id,
-                        lsp_server::ErrorCode::ContentModified as i32,
-                        "content modified".to_string(),
-                    )
-                } else {
-                    lsp_server::Response::new_err(
-                        id,
-                        lsp_server::ErrorCode::InternalError as i32,
-                        e.to_string(),
-                    )
-                }
-            }
+            Err(e) => match e.downcast::<Cancelled>() {
+                Ok(cancelled) => return Err(*cancelled),
+                Err(e) => lsp_server::Response::new_err(
+                    id,
+                    lsp_server::ErrorCode::InternalError as i32,
+                    e.to_string(),
+                ),
+            },
         },
-    }
+    };
+    Ok(res)
 }
 
 pub(crate) struct NotificationDispatcher<'a> {