From 960bc9f13446e1fbcc36f1a3be3541ec1b9ec5bd Mon Sep 17 00:00:00 2001
From: Egor Karavaev <batonius.kirov@gmail.com>
Date: Mon, 7 Jun 2021 21:50:20 +0300
Subject: [PATCH] Don't panic on LSP not starting

---
 helix-lsp/src/client.rs  |  2 +-
 helix-lsp/src/lib.rs     | 43 ++++++++++++++++++++--------------------
 helix-view/src/editor.rs |  4 ++--
 3 files changed, 25 insertions(+), 24 deletions(-)

diff --git a/helix-lsp/src/client.rs b/helix-lsp/src/client.rs
index a1c1134ad..41c38fd94 100644
--- a/helix-lsp/src/client.rs
+++ b/helix-lsp/src/client.rs
@@ -153,7 +153,7 @@ impl Client {
             timeout(Duration::from_secs(2), rx.recv())
                 .await
                 .map_err(|_| Error::Timeout)? // return Timeout
-                .unwrap() // TODO: None if channel closed
+                .ok_or(Error::StreamClosed)?
         }
     }
 
diff --git a/helix-lsp/src/lib.rs b/helix-lsp/src/lib.rs
index eeb2cdbbf..af8c90058 100644
--- a/helix-lsp/src/lib.rs
+++ b/helix-lsp/src/lib.rs
@@ -13,7 +13,10 @@ use helix_core::syntax::LanguageConfiguration;
 
 use thiserror::Error;
 
-use std::{collections::HashMap, sync::Arc};
+use std::{
+    collections::{hash_map::Entry, HashMap},
+    sync::Arc,
+};
 
 use serde::{Deserialize, Serialize};
 
@@ -29,6 +32,10 @@ pub enum Error {
     Parse(#[from] serde_json::Error),
     #[error("request timed out")]
     Timeout,
+    #[error("server closed the stream")]
+    StreamClosed,
+    #[error("LSP not defined")]
+    LspNotDefined,
     #[error(transparent)]
     Other(#[from] anyhow::Error),
 }
@@ -173,7 +180,7 @@ type LanguageId = String;
 use futures_util::stream::select_all::SelectAll;
 
 pub struct Registry {
-    inner: HashMap<LanguageId, Option<Arc<Client>>>,
+    inner: HashMap<LanguageId, Arc<Client>>,
 
     pub incoming: SelectAll<UnboundedReceiverStream<Call>>,
 }
@@ -192,35 +199,29 @@ impl Registry {
         }
     }
 
-    pub fn get(&mut self, language_config: &LanguageConfiguration) -> Option<Arc<Client>> {
-        // TODO: propagate the error
+    pub fn get(&mut self, language_config: &LanguageConfiguration) -> Result<Arc<Client>> {
         if let Some(config) = &language_config.language_server {
             // avoid borrow issues
             let inner = &mut self.inner;
             let s_incoming = &mut self.incoming;
 
-            let language_server = inner
-                .entry(language_config.scope.clone()) // can't use entry with Borrow keys: https://github.com/rust-lang/rfcs/pull/1769
-                .or_insert_with(|| {
-                    // TODO: lookup defaults for id (name, args)
-
+            match inner.entry(language_config.scope.clone()) {
+                Entry::Occupied(language_server) => Ok(language_server.get().clone()),
+                Entry::Vacant(entry) => {
                     // initialize a new client
-                    let (mut client, incoming) =
-                        Client::start(&config.command, &config.args).ok()?;
-
+                    let (mut client, incoming) = Client::start(&config.command, &config.args)?;
                     // TODO: run this async without blocking
-                    futures_executor::block_on(client.initialize()).unwrap();
-
+                    futures_executor::block_on(client.initialize())?;
                     s_incoming.push(UnboundedReceiverStream::new(incoming));
+                    let client = Arc::new(client);
 
-                    Some(Arc::new(client))
-                })
-                .clone();
-
-            return language_server;
+                    entry.insert(client.clone());
+                    Ok(client)
+                }
+            }
+        } else {
+            Err(Error::LspNotDefined)
         }
-
-        None
     }
 }
 
diff --git a/helix-view/src/editor.rs b/helix-view/src/editor.rs
index b69ae22f5..7af19a9b8 100644
--- a/helix-view/src/editor.rs
+++ b/helix-view/src/editor.rs
@@ -155,7 +155,7 @@ impl Editor {
             let language_server = doc
                 .language
                 .as_ref()
-                .and_then(|language| self.language_servers.get(language));
+                .and_then(|language| self.language_servers.get(language).ok());
 
             if let Some(language_server) = language_server {
                 doc.set_language_server(Some(language_server.clone()));
@@ -196,7 +196,7 @@ impl Editor {
             let language_server = doc
                 .language
                 .as_ref()
-                .and_then(|language| language_servers.get(language));
+                .and_then(|language| language_servers.get(language).ok());
             if let Some(language_server) = language_server {
                 tokio::spawn(language_server.text_document_did_close(doc.identifier()));
             }