fix: withSession

Author: nbbeeken

src/mongo_client.ts

@@ -642,16 +642,14 @@ export class MongoClient extends TypedEventEmitter<MongoClientEvents> {
     }
 
     const session = this.startSession(options);
-    const PromiseConstructor = PromiseProvider.get() ?? Promise;
-
-    return PromiseConstructor.resolve()
-      .then(() => withSessionCallback(session))
-      .then(() => {
-        // Do not return the result of callback
-      })
-      .finally(() => {
+
+    return maybeCallback(async () => {
+      try {
+        await withSessionCallback(session);
+      } finally {
         session.endSession().catch(() => null);
-      });
+      }
+    }, null);
   }
 
   /**

src/utils.ts

@@ -438,9 +438,14 @@ export function* makeCounter(seed = 0): Generator<number> {
 /**
  * Helper for handling legacy callback support.
  */
+export function maybeCallback<T>(promiseFn: () => Promise<T>, callback: null): Promise<T>;
 export function maybeCallback<T>(
   promiseFn: () => Promise<T>,
   callback?: Callback<T>
+): Promise<T> | void;
+export function maybeCallback<T>(
+  promiseFn: () => Promise<T>,
+  callback?: Callback<T> | null
 ): Promise<T> | void {
   const PromiseConstructor = PromiseProvider.get();