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Code Issues

don't overload LS with completion resolve requests 

While moving completion resolve to the event system in #9668 we introduced what
is essentially a "DOS attack" on slow LSPs. Completion resolve requests were
made in the render loop and debounced with a timeout. Once the timeout expired
the resolve request was made. The problem is the next frame would immediately
request a new completion resolve request (and mark the old one as obsolete but
because LSP has no notion of cancelation the server would still process it). So
we were in essence sending one completion request to the server every 150ms and
only stopped if the server managed to respond before we rendered a new frame.
This caused overload on slower machines/with slower LS.

In this PR I revamped the resolve handler so that a request is only ever
resolved once. Both by checking if a request is already in-flight and by marking
failed resolve requests as resolved.
This commit is contained in:
Pascal Kuthe 2024-04-21 16:14:39 +02:00 committed by Blaž Hrastnik
parent b834806dbc
commit 38ee845b05
6 changed files with 194 additions and 120 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
helix-lsp/src/client.rs
View File

@ -397,6 +397,16 @@ fn call<R: lsp::request::Request>(
&self,
params: R::Params,
) -> impl Future<Output = Result<Value>>
where
R::Params: serde::Serialize,
{
self.call_with_ref::<R>(&params)
}
fn call_with_ref<R: lsp::request::Request>(
&self,
params: &R::Params,
) -> impl Future<Output = Result<Value>>
where
R::Params: serde::Serialize,
{
@ -405,7 +415,7 @@ fn call<R: lsp::request::Request>(
fn call_with_timeout<R: lsp::request::Request>(
&self,
params: R::Params,
params: &R::Params,
timeout_secs: u64,
) -> impl Future<Output = Result<Value>>
where
@ -414,17 +424,16 @@ fn call_with_timeout<R: lsp::request::Request>(
let server_tx = self.server_tx.clone();
let id = self.next_request_id();
let params = serde_json::to_value(params);
async move {
use std::time::Duration;
use tokio::time::timeout;
let params = serde_json::to_value(params)?;
let request = jsonrpc::MethodCall {
jsonrpc: Some(jsonrpc::Version::V2),
id: id.clone(),
method: R::METHOD.to_string(),
params: Self::value_into_params(params),
params: Self::value_into_params(params?),
};
let (tx, mut rx) = channel::<Result<Value>>(1);
@ -741,7 +750,7 @@ pub fn will_rename(
new_uri: url_from_path(new_path)?,
}];
let request = self.call_with_timeout::<lsp::request::WillRenameFiles>(
lsp::RenameFilesParams { files },
&lsp::RenameFilesParams { files },
5,
);
@ -1026,21 +1035,10 @@ pub fn completion(
pub fn resolve_completion_item(
&self,
completion_item: lsp::CompletionItem,
) -> Option<impl Future<Output = Result<lsp::CompletionItem>>> {
let capabilities = self.capabilities.get().unwrap();
// Return early if the server does not support resolving completion items.
match capabilities.completion_provider {
Some(lsp::CompletionOptions {
resolve_provider: Some(true),
..
}) => (),
_ => return None,
}
let res = self.call::<lsp::request::ResolveCompletionItem>(completion_item);
Some(async move { Ok(serde_json::from_value(res.await?)?) })
completion_item: &lsp::CompletionItem,
) -> impl Future<Output = Result<lsp::CompletionItem>> {
let res = self.call_with_ref::<lsp::request::ResolveCompletionItem>(completion_item);
async move { Ok(serde_json::from_value(res.await?)?) }
}
pub fn resolve_code_action(

2
helix-term/src/handlers.rs
View File

@ -11,7 +11,7 @@
pub use completion::trigger_auto_completion;
pub use helix_view::handlers::Handlers;
mod completion;
pub mod completion;
mod signature_help;
pub fn setup(config: Arc<ArcSwap<Config>>) -> Handlers {

2
helix-term/src/handlers/completion.rs
View File

@ -30,6 +30,8 @@
use crate::ui::{self, CompletionItem, Popup};
use super::Handlers;
pub use resolve::ResolveHandler;
mod resolve;
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
enum TriggerKind {

153
helix-term/src/handlers/completion/resolve.rs Normal file
View File

@ -0,0 +1,153 @@
use std::sync::Arc;
use helix_lsp::lsp;
use tokio::sync::mpsc::Sender;
use tokio::time::{Duration, Instant};
use helix_event::{send_blocking, AsyncHook, CancelRx};
use helix_view::Editor;
use crate::handlers::completion::CompletionItem;
use crate::job;
/// A hook for resolving incomplete completion items.
///
/// From the [LSP spec](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_completion):
///
/// > If computing full completion items is expensive, servers can additionally provide a
/// > handler for the completion item resolve request. ...
/// > A typical use case is for example: the `textDocument/completion` request doesn't fill
/// > in the `documentation` property for returned completion items since it is expensive
/// > to compute. When the item is selected in the user interface then a
/// > 'completionItem/resolve' request is sent with the selected completion item as a parameter.
/// > The returned completion item should have the documentation property filled in.
pub struct ResolveHandler {
last_request: Option<Arc<CompletionItem>>,
resolver: Sender<ResolveRequest>,
}
impl ResolveHandler {
pub fn new() -> ResolveHandler {
ResolveHandler {
last_request: None,
resolver: ResolveTimeout {
next_request: None,
in_flight: None,
}
.spawn(),
}
}
pub fn ensure_item_resolved(&mut self, editor: &mut Editor, item: &mut CompletionItem) {
if item.resolved {
return;
}
let needs_resolve = item.item.documentation.is_none()
|| item.item.detail.is_none()
|| item.item.additional_text_edits.is_none();
if !needs_resolve {
item.resolved = true;
return;
}
if self.last_request.as_deref().is_some_and(|it| it == item) {
return;
}
let Some(ls) = editor.language_servers.get_by_id(item.provider).cloned() else {
item.resolved = true;
return;
};
if matches!(
ls.capabilities().completion_provider,
Some(lsp::CompletionOptions {
resolve_provider: Some(true),
..
})
) {
let item = Arc::new(item.clone());
self.last_request = Some(item.clone());
send_blocking(&self.resolver, ResolveRequest { item, ls })
} else {
item.resolved = true;
}
}
}
struct ResolveRequest {
item: Arc<CompletionItem>,
ls: Arc<helix_lsp::Client>,
}
#[derive(Default)]
struct ResolveTimeout {
next_request: Option<ResolveRequest>,
in_flight: Option<(helix_event::CancelTx, Arc<CompletionItem>)>,
}
impl AsyncHook for ResolveTimeout {
type Event = ResolveRequest;
fn handle_event(
&mut self,
request: Self::Event,
timeout: Option<tokio::time::Instant>,
) -> Option<tokio::time::Instant> {
if self
.next_request
.as_ref()
.is_some_and(|old_request| old_request.item == request.item)
{
timeout
} else if self
.in_flight
.as_ref()
.is_some_and(|(_, old_request)| old_request.item == request.item.item)
{
self.next_request = None;
None
} else {
self.next_request = Some(request);
Some(Instant::now() + Duration::from_millis(150))
}
}
fn finish_debounce(&mut self) {
let Some(request) = self.next_request.take() else { return };
let (tx, rx) = helix_event::cancelation();
self.in_flight = Some((tx, request.item.clone()));
tokio::spawn(request.execute(rx));
}
}
impl ResolveRequest {
async fn execute(self, cancel: CancelRx) {
let future = self.ls.resolve_completion_item(&self.item.item);
let Some(resolved_item) = helix_event::cancelable_future(future, cancel).await else {
return;
};
job::dispatch(move |_, compositor| {
if let Some(completion) = &mut compositor
.find::<crate::ui::EditorView>()
.unwrap()
.completion
{
let resolved_item = match resolved_item {
Ok(item) => CompletionItem {
item,
resolved: true,
..*self.item
},
Err(err) => {
log::error!("completion resolve request failed: {err}");
// set item to resolved so we don't request it again
// we could also remove it but that oculd be odd ui
let mut item = (*self.item).clone();
item.resolved = true;
item
}
};
completion.replace_item(&self.item, resolved_item);
};
})
.await
}
}

115
helix-term/src/ui/completion.rs
View File

@ -1,9 +1,7 @@
use crate::{
compositor::{Component, Context, Event, EventResult},
handlers::trigger_auto_completion,
job,
handlers::{completion::ResolveHandler, trigger_auto_completion},
};
use helix_event::AsyncHook;
use helix_view::{
document::SavePoint,
editor::CompleteAction,
@ -12,17 +10,16 @@
theme::{Modifier, Style},
ViewId,
};
use tokio::time::Instant;
use tui::{buffer::Buffer as Surface, text::Span};
use std::{borrow::Cow, sync::Arc, time::Duration};
use std::{borrow::Cow, sync::Arc};
use helix_core::{chars, Change, Transaction};
use helix_view::{graphics::Rect, Document, Editor};
use crate::ui::{menu, Markdown, Menu, Popup, PromptEvent};
use helix_lsp::{lsp, util, OffsetEncoding};
use helix_lsp::{lsp, util, LanguageServerId, OffsetEncoding};
impl menu::Item for CompletionItem {
type Data = ();
@ -104,7 +101,7 @@ pub struct Completion {
#[allow(dead_code)]
trigger_offset: usize,
filter: String,
resolve_handler: tokio::sync::mpsc::Sender<CompletionItem>,
resolve_handler: ResolveHandler,
}
impl Completion {
@ -365,7 +362,7 @@ macro_rules! language_server {
// TODO: expand nucleo api to allow moving straight to a Utf32String here
// and avoid allocation during matching
filter: String::from(fragment),
resolve_handler: ResolveHandler::default().spawn(),
resolve_handler: ResolveHandler::new(),
};
// need to recompute immediately in case start_offset != trigger_offset
@ -383,7 +380,16 @@ fn resolve_completion_item(
language_server: &helix_lsp::Client,
completion_item: lsp::CompletionItem,
) -> Option<lsp::CompletionItem> {
let future = language_server.resolve_completion_item(completion_item)?;
if !matches!(
language_server.capabilities().completion_provider,
Some(lsp::CompletionOptions {
resolve_provider: Some(true),
..
})
) {
return None;
}
let future = language_server.resolve_completion_item(&completion_item);
let response = helix_lsp::block_on(future);
match response {
Ok(item) => Some(item),
@ -416,7 +422,7 @@ pub fn is_empty(&self) -> bool {
self.popup.contents().is_empty()
}
fn replace_item(&mut self, old_item: CompletionItem, new_item: CompletionItem) {
pub fn replace_item(&mut self, old_item: &CompletionItem, new_item: CompletionItem) {
self.popup.contents_mut().replace_option(old_item, new_item);
}
@ -438,12 +444,12 @@ fn render(&mut self, area: Rect, surface: &mut Surface, cx: &mut Context) {
self.popup.render(area, surface, cx);
// if we have a selection, render a markdown popup on top/below with info
let option = match self.popup.contents().selection() {
let option = match self.popup.contents_mut().selection_mut() {
Some(option) => option,
None => return,
};
if !option.resolved {
helix_event::send_blocking(&self.resolve_handler, option.clone());
self.resolve_handler.ensure_item_resolved(cx.editor, option);
}
// need to render:
// option.detail
@ -541,88 +547,3 @@ fn render(&mut self, area: Rect, surface: &mut Surface, cx: &mut Context) {
markdown_doc.render(doc_area, surface, cx);
}
}
/// A hook for resolving incomplete completion items.
///
/// From the [LSP spec](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_completion):
///
/// > If computing full completion items is expensive, servers can additionally provide a
/// > handler for the completion item resolve request. ...
/// > A typical use case is for example: the `textDocument/completion` request doesn't fill
/// > in the `documentation` property for returned completion items since it is expensive
/// > to compute. When the item is selected in the user interface then a
/// > 'completionItem/resolve' request is sent with the selected completion item as a parameter.
/// > The returned completion item should have the documentation property filled in.
#[derive(Debug, Default)]
struct ResolveHandler {
trigger: Option<CompletionItem>,
request: Option<helix_event::CancelTx>,
}
impl AsyncHook for ResolveHandler {
type Event = CompletionItem;
fn handle_event(
&mut self,
item: Self::Event,
timeout: Option<tokio::time::Instant>,
) -> Option<tokio::time::Instant> {
if self
.trigger
.as_ref()
.is_some_and(|trigger| trigger == &item)
{
timeout
} else {
self.trigger = Some(item);
self.request = None;
Some(Instant::now() + Duration::from_millis(150))
}
}
fn finish_debounce(&mut self) {
let Some(item) = self.trigger.take() else { return };
let (tx, rx) = helix_event::cancelation();
self.request = Some(tx);
job::dispatch_blocking(move |editor, _| resolve_completion_item(editor, item, rx))
}
}
fn resolve_completion_item(
editor: &mut Editor,
item: CompletionItem,
cancel: helix_event::CancelRx,
) {
let Some(language_server) = editor.language_server_by_id(item.language_server_id) else {
return;
};
let Some(future) = language_server.resolve_completion_item(item.item.clone()) else {
return;
};
tokio::spawn(async move {
match helix_event::cancelable_future(future, cancel).await {
Some(Ok(resolved_item)) => {
job::dispatch(move |_, compositor| {
if let Some(completion) = &mut compositor
.find::<crate::ui::EditorView>()
.unwrap()
.completion
{
let resolved_item = CompletionItem {
item: resolved_item,
language_server_id: item.language_server_id,
resolved: true,
};
completion.replace_item(item, resolved_item);
};
})
.await
}
Some(Err(err)) => log::error!("completion resolve request failed: {err}"),
None => (),
}
});
}

4
helix-term/src/ui/menu.rs
View File

@ -241,9 +241,9 @@ pub fn len(&self) -> usize {
}
impl<T: Item + PartialEq> Menu<T> {
pub fn replace_option(&mut self, old_option: T, new_option: T) {
pub fn replace_option(&mut self, old_option: &T, new_option: T) {
for option in &mut self.options {
if old_option == *option {
if old_option == option {
*option = new_option;
break;
}