test(NODE-6692): check that event emitters have error listeners (#4382)

Co-authored-by: Durran Jordan <[email protected]>

Author: nbbeeken

.eslintrc.json

@@ -119,6 +119,10 @@
       {
         "selector": "BinaryExpression[operator=/[=!]==?/] Literal[value='undefined']",
         "message": "Do not strictly check typeof undefined (NOTE: currently this rule only detects the usage of 'undefined' string literal so this could be a misfire)"
+      },
+      {
+        "selector": "CallExpression[callee.property.name='removeAllListeners'][arguments.length=0]",
+        "message": "removeAllListeners can remove error listeners leading to uncaught errors"
       }
     ],
     "@typescript-eslint/no-unused-vars": "error",

.mocharc.json

@@ -4,7 +4,7 @@
     "source-map-support/register",
     "ts-node/register",
     "test/tools/runner/chai_addons.ts",
-    "test/tools/runner/hooks/unhandled_checker.ts"
+    "test/tools/runner/ee_checker.ts"
   ],
   "extension": [
     "js",

src/change_stream.ts

@@ -951,12 +951,10 @@ export class ChangeStream<
 
   /** @internal */
   private _endStream(): void {
-    const cursorStream = this.cursorStream;
-    if (cursorStream) {
-      ['data', 'close', 'end', 'error'].forEach(event => cursorStream.removeAllListeners(event));
-      cursorStream.destroy();
-    }
-
+    this.cursorStream?.removeAllListeners('data');
+    this.cursorStream?.removeAllListeners('close');
+    this.cursorStream?.removeAllListeners('end');
+    this.cursorStream?.destroy();
     this.cursorStream = undefined;
   }
 

src/client-side-encryption/state_machine.ts

@@ -344,7 +344,6 @@ export class StateMachine {
     function destroySockets() {
       for (const sock of [socket, netSocket]) {
         if (sock) {
-          sock.removeAllListeners();
           sock.destroy();
         }
       }

src/cmap/connect.ts

@@ -427,7 +427,6 @@ export async function makeSocket(options: MakeConnectionOptions): Promise<Stream
     throw error;
   } finally {
     socket.setTimeout(0);
-    socket.removeAllListeners();
     if (cancellationHandler != null) {
       options.cancellationToken?.removeListener('cancel', cancellationHandler);
     }

src/cmap/connection.ts

@@ -46,6 +46,7 @@ import {
   HostAddress,
   maxWireVersion,
   type MongoDBNamespace,
+  noop,
   now,
   once,
   squashError,
@@ -229,6 +230,7 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
 
   constructor(stream: Stream, options: ConnectionOptions) {
     super();
+    this.on('error', noop);
 
     this.socket = stream;
     this.id = options.id;

src/cmap/connection_pool.ts

@@ -34,6 +34,7 @@ import {
   kDispose,
   List,
   makeCounter,
+  noop,
   now,
   promiseWithResolvers
 } from '../utils';
@@ -200,6 +201,7 @@ export class ConnectionPool extends TypedEventEmitter<ConnectionPoolEvents> {
 
   constructor(server: Server, options: ConnectionPoolOptions) {
     super();
+    this.on('error', noop);
 
     this.options = Object.freeze({
       connectionType: Connection,

src/cursor/abstract_cursor.ts

@@ -27,6 +27,7 @@ import {
   type Disposable,
   kDispose,
   type MongoDBNamespace,
+  noop,
   squashError
 } from '../utils';
 
@@ -267,6 +268,7 @@ export abstract class AbstractCursor<
     options: AbstractCursorOptions & Abortable = {}
   ) {
     super();
+    this.on('error', noop);
 
     if (!client.s.isMongoClient) {
       throw new MongoRuntimeError('Cursor must be constructed with MongoClient');

src/gridfs/index.ts

@@ -7,7 +7,7 @@ import { type Filter, TypedEventEmitter } from '../mongo_types';
 import type { ReadPreference } from '../read_preference';
 import type { Sort } from '../sort';
 import { CSOTTimeoutContext } from '../timeout';
-import { resolveOptions } from '../utils';
+import { noop, resolveOptions } from '../utils';
 import { WriteConcern, type WriteConcernOptions } from '../write_concern';
 import type { FindOptions } from './../operations/find';
 import {
@@ -87,6 +87,7 @@ export class GridFSBucket extends TypedEventEmitter<GridFSBucketEvents> {
 
   constructor(db: Db, options?: GridFSBucketOptions) {
     super();
+    this.on('error', noop);
     this.setMaxListeners(0);
     const privateOptions = resolveOptions(db, {
       ...DEFAULT_GRIDFS_BUCKET_OPTIONS,

src/mongo_client.ts

@@ -57,6 +57,7 @@ import {
   hostMatchesWildcards,
   isHostMatch,
   type MongoDBNamespace,
+  noop,
   ns,
   resolveOptions,
   squashError
@@ -381,6 +382,7 @@ export class MongoClient extends TypedEventEmitter<MongoClientEvents> implements
 
   constructor(url: string, options?: MongoClientOptions) {
     super();
+    this.on('error', noop);
 
     this.options = parseOptions(url, this, options);