From 6453b29cb571d5c54bac427842ba8a9dd6874861 Mon Sep 17 00:00:00 2001
From: "Jeremy A. Kolb" <jkolb@ara.com>
Date: Mon, 22 Oct 2018 13:49:27 -0400
Subject: Add LspError to explicity return errors from LSP handlers

Fixes #145
---
 crates/ra_lsp_server/src/main_loop/handlers.rs |  5 +++--
 crates/ra_lsp_server/src/main_loop/mod.rs      | 18 +++++++++++++++++-
 2 files changed, 20 insertions(+), 3 deletions(-)

(limited to 'crates/ra_lsp_server/src/main_loop')

diff --git a/crates/ra_lsp_server/src/main_loop/handlers.rs b/crates/ra_lsp_server/src/main_loop/handlers.rs
index f5dff4c80..baf82f3fc 100644
--- a/crates/ra_lsp_server/src/main_loop/handlers.rs
+++ b/crates/ra_lsp_server/src/main_loop/handlers.rs
@@ -7,6 +7,7 @@ use languageserver_types::{
     InsertTextFormat, Location, Position, SymbolInformation, TextDocumentIdentifier, TextEdit,
     RenameParams, WorkspaceEdit, PrepareRenameResponse
 };
+use gen_lsp_server::ErrorCode;
 use ra_analysis::{FileId, FoldKind, Query, RunnableKind};
 use ra_syntax::text_utils::contains_offset_nonstrict;
 use serde_json::to_value;
@@ -16,7 +17,7 @@ use crate::{
     project_model::TargetKind,
     req::{self, Decoration},
     server_world::ServerWorld,
-    Result,
+    Result, LspError
 };
 
 pub fn handle_syntax_tree(
@@ -476,7 +477,7 @@ pub fn handle_rename(
     let offset = params.position.conv_with(&line_index);
 
     if params.new_name.is_empty() {
-        return Ok(None);
+        return Err(LspError::new(ErrorCode::InvalidParams as i32, "New Name cannot be empty".into()).into());
     }
 
     let refs = world.analysis().find_all_refs(file_id, offset)?;
diff --git a/crates/ra_lsp_server/src/main_loop/mod.rs b/crates/ra_lsp_server/src/main_loop/mod.rs
index b35ebd38b..aa3cf1dbd 100644
--- a/crates/ra_lsp_server/src/main_loop/mod.rs
+++ b/crates/ra_lsp_server/src/main_loop/mod.rs
@@ -23,6 +23,19 @@ use crate::{
     Result,
 };
 
+#[derive(Debug, Fail)]
+#[fail(display = "Language Server request failed with {}. ({})", code, message)]
+pub struct LspError {
+    pub code: i32,
+    pub message: String,
+}
+
+impl LspError {
+    pub fn new(code: i32, message: String) -> LspError {
+        LspError {code, message}
+    }
+}
+
 #[derive(Debug)]
 enum Task {
     Respond(RawResponse),
@@ -361,7 +374,10 @@ impl<'a> PoolDispatcher<'a> {
                     let resp = match f(world, params) {
                         Ok(resp) => RawResponse::ok::<R>(id, &resp),
                         Err(e) => {
-                            RawResponse::err(id, ErrorCode::InternalError as i32, e.to_string())
+                            match e.downcast::<LspError>() {
+                                Ok(lsp_error) => RawResponse::err(id, lsp_error.code, lsp_error.message),
+                                Err(e) => RawResponse::err(id, ErrorCode::InternalError as i32, e.to_string())
+                            }
                         }
                     };
                     let task = Task::Respond(resp);
-- 
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