Auto merge of #15846 - jprochazk:disable-error-notification, r=Veykril

editor/code: add option to suppress error notifications

Fixes https://github.com/rust-lang/rust-analyzer/issues/14193

- Added the `rust-analyzer.showRequestFailedErrorNotification` configuration option, which defaults to `true`
- If `rust-analyzer.showRequestFailedErrorNotification` is set to `true`, the current behavior is preserved.
- If `rust-analyzer.showRequestFailedErrorNotification` is set to `false`, no error toasts will be displayed for any of the failed requests caused by panics in r-a. This _only_ applies to events that are triggered "implicitly", such as `textDocument/hover`.

To test this, you can manually introduce a panic in one of the language server LSP handlers for non-command events. I added an explicit `panic!()` in the `textDocument/hover` event handler:

#### `rust-analyzer.showRequestFailedErrorNotification` set to `true` (default)

[2023-11-07 17-17-48.webm](https://github.com/rust-lang/rust-analyzer/assets/1665677/d0408ab8-79d1-42cf-a4e7-94e99d9783ec)

#### `rust-analyzer.showRequestFailedErrorNotification` set to `false`

[2023-11-07 17-16-49.webm](https://github.com/rust-lang/rust-analyzer/assets/1665677/0496d8d0-fb53-4bc6-a279-1a47f412dbdb)

3 files changed, 33 insertions, 1 deletions

diff --git a/editors/code/package.json b/editors/code/package.json
index 265c63f3e2d..c43f2b964fd 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json
@@ -498,6 +498,11 @@
                     "default": true,
                     "type": "boolean"
                 },
+                "rust-analyzer.showRequestFailedErrorNotification": {
+                    "markdownDescription": "Whether to show error notifications for failing requests.",
+                    "default": true,
+                    "type": "boolean"
+                },
                 "rust-analyzer.showDependenciesExplorer": {
                     "markdownDescription": "Whether to show the dependencies view.",
                     "default": true,
diff --git a/editors/code/src/client.ts b/editors/code/src/client.ts
index 96e888402ba..c27a446b380 100644
--- a/editors/code/src/client.ts
+++ b/editors/code/src/client.ts
@@ -10,6 +10,7 @@ import { type Config, prepareVSCodeConfig } from "./config";
 import { randomUUID } from "crypto";
 import { sep as pathSeparator } from "path";
 import { unwrapUndefinable } from "./undefinable";
+import { RaLanguageClient } from "./lang_client";
 
 export interface Env {
     [name: string]: string;
@@ -363,7 +364,7 @@ export async function createClient(
         },
     };
 
-    const client = new lc.LanguageClient(
+    const client = new RaLanguageClient(
         "rust-analyzer",
         "Rust Analyzer Language Server",
         serverOptions,
diff --git a/editors/code/src/lang_client.ts b/editors/code/src/lang_client.ts
new file mode 100644
index 00000000000..09d64efc048
--- /dev/null
+++ b/editors/code/src/lang_client.ts
@@ -0,0 +1,26 @@
+import * as lc from "vscode-languageclient/node";
+import * as vscode from "vscode";
+
+export class RaLanguageClient extends lc.LanguageClient {
+    override handleFailedRequest<T>(
+        type: lc.MessageSignature,
+        token: vscode.CancellationToken | undefined,
+        error: any,
+        defaultValue: T,
+        showNotification?: boolean | undefined,
+    ): T {
+        const showError = vscode.workspace
+            .getConfiguration("rust-analyzer")
+            .get("showRequestFailedErrorNotification");
+        if (
+            !showError &&
+            error instanceof lc.ResponseError &&
+            error.code === lc.ErrorCodes.InternalError
+        ) {
+            // Don't show notification for internal errors, these are emitted by r-a when a request fails.
+            showNotification = false;
+        }
+
+        return super.handleFailedRequest(type, token, error, defaultValue, showNotification);
+    }
+}