close cursor on error from transform

Author: baileympearson

src/cursor/abstract_cursor.ts

@@ -705,7 +705,12 @@ async function next<T>(
     const doc = cursor[kDocuments].shift();
 
     if (doc != null && transform && cursor[kTransform]) {
-      return cursor[kTransform](doc);
+      try {
+        return cursor[kTransform](doc);
+      } catch (error) {
+        await cleanupCursorAsync(cursor, { error, needsToEmitClosed: true });
+        throw error;
+      }
     }
 
     return doc;

test/integration/node-specific/abstract_cursor.test.ts

@@ -5,7 +5,7 @@ import { inspect } from 'util';
 
 import { type Collection, type FindCursor, MongoAPIError, type MongoClient } from '../../mongodb';
 
-describe('class AbstractCursor', function () {
+describe.only('class AbstractCursor', function () {
   describe('regression tests NODE-5372', function () {
     let client: MongoClient;
     let collection: Collection;
@@ -38,7 +38,7 @@ describe('class AbstractCursor', function () {
     });
   });
 
-  describe('cursor iteration APIs', function () {
+  describe.only('cursor iteration APIs', function () {
     let client: MongoClient;
     let collection: Collection;
     const transformSpy = sinon.spy(doc => ({ ...doc, name: doc.name.toUpperCase() }));
@@ -96,7 +96,6 @@ describe('class AbstractCursor', function () {
           expect(doc.name).to.equal('JOHN DOE');
         });
 
-        // skipped because these tests fail after throwing uncaught exceptions
         it(`when the transform throws, ${method}() propagates the error to the user`, async () => {
           const cursor = collection.find().map(() => {
             throw new Error('error thrown in transform');
@@ -106,6 +105,7 @@ describe('class AbstractCursor', function () {
           expect(error)
             .to.be.instanceOf(Error)
             .to.match(/error thrown in transform/);
+          expect(cursor.closed).to.be.true;
         });
       }
 
@@ -130,6 +130,7 @@ describe('class AbstractCursor', function () {
         expect(error)
           .to.be.instanceOf(Error)
           .to.match(/error thrown in transform/);
+        expect(cursor._cursor).to.have.property('closed', true);
       });
     });