From 791029fcac2c898c3f60463e5d59da342700c3d9 Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Tue, 3 Sep 2024 16:23:47 -0400
Subject: [PATCH 01/22] initial commit

---
 src/cmap/commands.ts                                |  2 +-
 .../read-write-concern/write_concern.test.ts        |  5 +++--
 test/unit/commands.test.ts                          | 13 +++++++++++++
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/src/cmap/commands.ts b/src/cmap/commands.ts
index 19dd8e1a657..954455bc154 100644
--- a/src/cmap/commands.ts
+++ b/src/cmap/commands.ts
@@ -450,7 +450,7 @@ export class OpMsgRequest {
 
     // flags
     this.checksumPresent = false;
-    this.moreToCome = options.moreToCome || false;
+    this.moreToCome = options.moreToCome || options.writeConcern?.w === 0 || false;
     this.exhaustAllowed =
       typeof options.exhaustAllowed === 'boolean' ? options.exhaustAllowed : false;
   }
diff --git a/test/integration/read-write-concern/write_concern.test.ts b/test/integration/read-write-concern/write_concern.test.ts
index 58901e513b5..c995a1b928a 100644
--- a/test/integration/read-write-concern/write_concern.test.ts
+++ b/test/integration/read-write-concern/write_concern.test.ts
@@ -11,7 +11,7 @@ import {
 import * as mock from '../../tools/mongodb-mock/index';
 import { filterForCommands } from '../shared';
 
-describe('Write Concern', function () {
+describe.only('Write Concern', function () {
   context('when the WriteConcern is set in the uri', function () {
     let client;
     const events: CommandStartedEvent[] = [];
@@ -29,7 +29,8 @@ describe('Write Concern', function () {
       expect(events[0]).to.containSubset({
         commandName: 'insert',
         command: {
-          writeConcern: { w: 0 }
+          writeConcern: { w: 0 },
+          moreToCome: true
         }
       });
     });
diff --git a/test/unit/commands.test.ts b/test/unit/commands.test.ts
index f6ba300b7aa..93831530955 100644
--- a/test/unit/commands.test.ts
+++ b/test/unit/commands.test.ts
@@ -6,6 +6,8 @@ import * as compression from '../../src/cmap/wire_protocol/compression';
 import {
   compress,
   Compressor,
+  Connection,
+  MongoClient,
   OP_MSG,
   OP_QUERY,
   OpCompressedRequest,
@@ -109,3 +111,14 @@ describe('class OpCompressedRequest', () => {
     }
   });
 });
+
+describe.only('fire-and-forget', () => {
+  describe('OpMsgRequest', () => {
+    context('when writeConcern.w is 0', () => {
+      it('moreToCome is set to true', async () => {
+        const request = new OpMsgRequest('db', { a: 1 }, { writeConcern: { w: 0 } });
+        expect(request.moreToCome).to.be.true;
+      });
+    });
+  });
+});

From d1a1931a460b0b17c6083b603e54bdbdf6932423 Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Tue, 3 Sep 2024 18:15:27 -0400
Subject: [PATCH 02/22] enforce no response when moreToCome is set

---
 src/cmap/connection.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/cmap/connection.ts b/src/cmap/connection.ts
index 1e4afc7f387..8a52f4e71bc 100644
--- a/src/cmap/connection.ts
+++ b/src/cmap/connection.ts
@@ -438,7 +438,7 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
         zlibCompressionLevel: this.description.zlibCompressionLevel
       });
 
-      if (options.noResponse) {
+      if (options.noResponse || ('moreToCome' in message && message?.moreToCome)) {
         yield MongoDBResponse.empty;
         return;
       }

From ebd4b44854cf8048016eff515e50d9a4aa82ea6f Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Fri, 6 Sep 2024 16:54:49 -0400
Subject: [PATCH 03/22] ready for review

lint fix

lont fix 2
---
 src/cmap/commands.ts                          |   2 +-
 src/cmap/connection.ts                        |  12 +-
 .../read-write-concern/write_concern.test.ts  | 143 +++++++++++++++++-
 test/unit/commands.test.ts                    |  10 +-
 4 files changed, 152 insertions(+), 15 deletions(-)

diff --git a/src/cmap/commands.ts b/src/cmap/commands.ts
index ff9636f1828..a7554ff8819 100644
--- a/src/cmap/commands.ts
+++ b/src/cmap/commands.ts
@@ -465,7 +465,7 @@ export class OpMsgRequest {
 
     // flags
     this.checksumPresent = false;
-    this.moreToCome = options.moreToCome || options.writeConcern?.w === 0 || false;
+    this.moreToCome = options.moreToCome || command.writeConcern?.w === 0 || false;
     this.exhaustAllowed =
       typeof options.exhaustAllowed === 'boolean' ? options.exhaustAllowed : false;
   }
diff --git a/src/cmap/connection.ts b/src/cmap/connection.ts
index f6a178f9797..be819c7a6cc 100644
--- a/src/cmap/connection.ts
+++ b/src/cmap/connection.ts
@@ -438,7 +438,7 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
         zlibCompressionLevel: this.description.zlibCompressionLevel
       });
 
-      if (options.noResponse || ('moreToCome' in message && message?.moreToCome)) {
+      if (options.noResponse) {
         yield MongoDBResponse.empty;
         return;
       }
@@ -500,9 +500,13 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
     let document: MongoDBResponse | undefined = undefined;
     /** Cached result of a toObject call */
     let object: Document | undefined = undefined;
+    const wireOptions = options;
+    if (message instanceof OpMsgRequest) {
+      wireOptions.noResponse = options.noResponse || message.moreToCome;
+    }
     try {
       this.throwIfAborted();
-      for await (document of this.sendWire(message, options, responseType)) {
+      for await (document of this.sendWire(message, wireOptions, responseType)) {
         object = undefined;
         if (options.session != null) {
           updateSessionFromResponse(options.session, document);
@@ -526,7 +530,7 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
             new CommandSucceededEvent(
               this,
               message,
-              options.noResponse ? undefined : (object ??= document.toObject(bsonOptions)),
+              wireOptions.noResponse ? { ok: 1 } : (object ??= document.toObject(bsonOptions)),
               started,
               this.description.serverConnectionId
             )
@@ -629,8 +633,8 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
           });
 
     const buffer = Buffer.concat(await finalCommand.toBin());
-
     if (this.socket.write(buffer)) return;
+
     return await once(this.socket, 'drain');
   }
 
diff --git a/test/integration/read-write-concern/write_concern.test.ts b/test/integration/read-write-concern/write_concern.test.ts
index c995a1b928a..b00e971312d 100644
--- a/test/integration/read-write-concern/write_concern.test.ts
+++ b/test/integration/read-write-concern/write_concern.test.ts
@@ -1,17 +1,21 @@
 import { expect } from 'chai';
 import { on, once } from 'events';
+import { gte } from 'semver';
+import * as sinon from 'sinon';
 
 import {
   type Collection,
   type CommandStartedEvent,
+  type CommandSucceededEvent,
   type Db,
   LEGACY_HELLO_COMMAND,
-  MongoClient
+  MongoClient,
+  OpMsgRequest
 } from '../../mongodb';
 import * as mock from '../../tools/mongodb-mock/index';
 import { filterForCommands } from '../shared';
 
-describe.only('Write Concern', function () {
+describe('Write Concern', function () {
   context('when the WriteConcern is set in the uri', function () {
     let client;
     const events: CommandStartedEvent[] = [];
@@ -29,8 +33,7 @@ describe.only('Write Concern', function () {
       expect(events[0]).to.containSubset({
         commandName: 'insert',
         command: {
-          writeConcern: { w: 0 },
-          moreToCome: true
+          writeConcern: { w: 0 }
         }
       });
     });
@@ -169,4 +172,136 @@ describe.only('Write Concern', function () {
       });
     });
   });
+
+  describe('fire-and-forget protocol', function () {
+    context('when writeConcern = 0 and OP_MSG is used', function () {
+      const writeOperations: { name: string; command: any; expectedReturnVal: any }[] = [
+        {
+          name: 'insertOne',
+          command: client => client.db('test').collection('test').insertOne({ a: 1 }),
+          expectedReturnVal: { acknowledged: false }
+        },
+        {
+          name: 'insertMany',
+          command: client =>
+            client
+              .db('test')
+              .collection('test')
+              .insertMany([{ a: 1 }, { b: 2 }]),
+          expectedReturnVal: { acknowledged: false }
+        },
+        {
+          name: 'updateOne',
+          command: client =>
+            client
+              .db('test')
+              .collection('test')
+              .updateOne({ i: 128 }, { $set: { c: 2 } }),
+          expectedReturnVal: { acknowledged: false }
+        },
+        {
+          name: 'updateMany',
+          command: client =>
+            client
+              .db('test')
+              .collection('test')
+              .updateMany({ name: 'foobar' }, { $set: { name: 'fizzbuzz' } }),
+          expectedReturnVal: { acknowledged: false }
+        },
+        {
+          name: 'deleteOne',
+          command: client => client.db('test').collection('test').deleteOne({ a: 1 }),
+          expectedReturnVal: { acknowledged: false }
+        },
+        {
+          name: 'deleteMany',
+          command: client => client.db('test').collection('test').deleteMany({ name: 'foobar' }),
+          expectedReturnVal: { acknowledged: false }
+        },
+        {
+          name: 'replaceOne',
+          command: client => client.db('test').collection('test').replaceOne({ a: 1 }, { b: 2 }),
+          expectedReturnVal: { acknowledged: false }
+        },
+        {
+          name: 'removeUser',
+          command: client => client.db('test').removeUser('albert'),
+          expectedReturnVal: true
+        },
+        {
+          name: 'findAndModify',
+          command: client =>
+            client
+              .db('test')
+              .collection('test')
+              .findOneAndUpdate({}, { $setOnInsert: { a: 1 } }, { upsert: true }),
+          expectedReturnVal: null
+        },
+        {
+          name: 'dropDatabase',
+          command: client => client.db('test').dropDatabase(),
+          expectedReturnVal: true
+        },
+        {
+          name: 'dropCollection',
+          command: client => client.db('test').dropCollection('test'),
+          expectedReturnVal: true
+        },
+        {
+          name: 'dropIndexes',
+          command: client => client.db('test').collection('test').dropIndex('a'),
+          expectedReturnVal: { ok: 1 }
+        },
+        {
+          name: 'createIndexes',
+          command: client => client.db('test').collection('test').createIndex({ a: 1 }),
+          expectedReturnVal: 'a_1'
+        },
+        {
+          name: 'createCollection',
+          command: client => client.db('test').createCollection('test'),
+          expectedReturnVal: {}
+        }
+      ];
+
+      for (const op of writeOperations) {
+        context(`when the write operation ${op.name} is run`, function () {
+          let client;
+          let spy;
+
+          beforeEach(async function () {
+            if (gte('3.6.0', this.configuration.version)) {
+              this.currentTest.skipReason = 'Test requires OP_MSG, needs to be on MongoDB 3.6+';
+              this.skip();
+            }
+            spy = sinon.spy(OpMsgRequest.prototype, 'toBin');
+            client = this.configuration.newClient({ monitorCommands: true, w: 0 });
+            await client.connect();
+          });
+
+          afterEach(function () {
+            sinon.restore();
+            client.close();
+          });
+
+          it('the request should have moreToCome bit set', async function () {
+            await op.command(client);
+            expect(spy.returnValues[spy.returnValues.length - 1][0][16]).to.equal(2);
+          });
+
+          it('the return value of the command should be nullish', async function () {
+            const result = await op.command(client);
+            expect(result).to.containSubset(op.expectedReturnVal);
+          });
+
+          it('commandSucceededEvent should have reply with only {ok: 1}', async function () {
+            const events: CommandSucceededEvent[] = [];
+            client.on('commandSucceeded', event => events.push(event));
+            await op.command(client);
+            expect(events[0]).to.containSubset({ reply: { ok: 1 } });
+          });
+        });
+      }
+    });
+  });
 });
diff --git a/test/unit/commands.test.ts b/test/unit/commands.test.ts
index 93831530955..2b2cf5f58b4 100644
--- a/test/unit/commands.test.ts
+++ b/test/unit/commands.test.ts
@@ -6,8 +6,6 @@ import * as compression from '../../src/cmap/wire_protocol/compression';
 import {
   compress,
   Compressor,
-  Connection,
-  MongoClient,
   OP_MSG,
   OP_QUERY,
   OpCompressedRequest,
@@ -112,11 +110,11 @@ describe('class OpCompressedRequest', () => {
   });
 });
 
-describe.only('fire-and-forget', () => {
-  describe('OpMsgRequest', () => {
-    context('when writeConcern.w is 0', () => {
+describe('OpMsgRequest', () => {
+  describe('fire-and-forget', () => {
+    context('when writeConcern = 0', () => {
       it('moreToCome is set to true', async () => {
-        const request = new OpMsgRequest('db', { a: 1 }, { writeConcern: { w: 0 } });
+        const request = new OpMsgRequest('db', { a: 1, writeConcern: { w: 0 } }, {});
         expect(request.moreToCome).to.be.true;
       });
     });

From 86e1a917981c0e2a485dde994e72ac014b1197d2 Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Fri, 6 Sep 2024 17:04:51 -0400
Subject: [PATCH 04/22] tsdoc updateg

---
 src/write_concern.ts | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/write_concern.ts b/src/write_concern.ts
index 456b7e8d83b..8f2b288736a 100644
--- a/src/write_concern.ts
+++ b/src/write_concern.ts
@@ -58,7 +58,10 @@ interface CommandWriteConcernOptions {
  * @see https://www.mongodb.com/docs/manual/reference/write-concern/
  */
 export class WriteConcern {
-  /** Request acknowledgment that the write operation has propagated to a specified number of mongod instances or to mongod instances with specified tags. */
+  /** 
+   * Request acknowledgment that the write operation has propagated to a specified number of mongod instances or to mongod instances with specified tags. 
+   * If w is 0 and is set on the command in the request, the server will not send a response.
+  */
   readonly w?: W;
   /** Request acknowledgment that the write operation has been written to the on-disk journal */
   readonly journal?: boolean;

From d892ccca23654b109bf09d4b9b10e1b1bd5af47f Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Fri, 6 Sep 2024 17:19:46 -0400
Subject: [PATCH 05/22] lint fix

remove extra newline

remove extra newline
---
 src/cmap/connection.ts | 2 +-
 src/write_concern.ts   | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/cmap/connection.ts b/src/cmap/connection.ts
index be819c7a6cc..3cada6392cc 100644
--- a/src/cmap/connection.ts
+++ b/src/cmap/connection.ts
@@ -633,8 +633,8 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
           });
 
     const buffer = Buffer.concat(await finalCommand.toBin());
-    if (this.socket.write(buffer)) return;
 
+    if (this.socket.write(buffer)) return;
     return await once(this.socket, 'drain');
   }
 
diff --git a/src/write_concern.ts b/src/write_concern.ts
index 8f2b288736a..390646a3be0 100644
--- a/src/write_concern.ts
+++ b/src/write_concern.ts
@@ -58,10 +58,10 @@ interface CommandWriteConcernOptions {
  * @see https://www.mongodb.com/docs/manual/reference/write-concern/
  */
 export class WriteConcern {
-  /** 
-   * Request acknowledgment that the write operation has propagated to a specified number of mongod instances or to mongod instances with specified tags. 
-   * If w is 0 and is set on the command in the request, the server will not send a response.
-  */
+  /**
+   * Request acknowledgment that the write operation has propagated to a specified number of mongod instances or to mongod instances with specified tags.
+   * If w is 0 and is set on a write operation, the server will not send a response.
+   */
   readonly w?: W;
   /** Request acknowledgment that the write operation has been written to the on-disk journal */
   readonly journal?: boolean;

From 5df9384349fce91fa27a53e1bdaa99b6749e93a9 Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Mon, 9 Sep 2024 10:22:18 -0400
Subject: [PATCH 06/22] fix failing test

---
 src/cmap/connection.ts | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/cmap/connection.ts b/src/cmap/connection.ts
index 3cada6392cc..49726fdded1 100644
--- a/src/cmap/connection.ts
+++ b/src/cmap/connection.ts
@@ -438,7 +438,7 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
         zlibCompressionLevel: this.description.zlibCompressionLevel
       });
 
-      if (options.noResponse) {
+      if (options.noResponse || ('moreToCome' in message && message.moreToCome)) {
         yield MongoDBResponse.empty;
         return;
       }
@@ -500,13 +500,9 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
     let document: MongoDBResponse | undefined = undefined;
     /** Cached result of a toObject call */
     let object: Document | undefined = undefined;
-    const wireOptions = options;
-    if (message instanceof OpMsgRequest) {
-      wireOptions.noResponse = options.noResponse || message.moreToCome;
-    }
     try {
       this.throwIfAborted();
-      for await (document of this.sendWire(message, wireOptions, responseType)) {
+      for await (document of this.sendWire(message, options, responseType)) {
         object = undefined;
         if (options.session != null) {
           updateSessionFromResponse(options.session, document);
@@ -530,7 +526,11 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
             new CommandSucceededEvent(
               this,
               message,
-              wireOptions.noResponse ? { ok: 1 } : (object ??= document.toObject(bsonOptions)),
+              options.noResponse
+                ? undefined
+                : 'moreToCome' in message && message.moreToCome
+                  ? { ok: 1 }
+                  : (object ??= document.toObject(bsonOptions)),
               started,
               this.description.serverConnectionId
             )

From 1e522639495fdb4d473ef3e3e785f1dfcd9698b3 Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Mon, 9 Sep 2024 16:25:00 -0400
Subject: [PATCH 07/22] fix failing tests

---
 test/integration/read-write-concern/write_concern.test.ts | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/test/integration/read-write-concern/write_concern.test.ts b/test/integration/read-write-concern/write_concern.test.ts
index b00e971312d..9d479a22718 100644
--- a/test/integration/read-write-concern/write_concern.test.ts
+++ b/test/integration/read-write-concern/write_concern.test.ts
@@ -13,6 +13,7 @@ import {
   OpMsgRequest
 } from '../../mongodb';
 import * as mock from '../../tools/mongodb-mock/index';
+import { sleep } from '../../tools/utils';
 import { filterForCommands } from '../shared';
 
 describe('Write Concern', function () {
@@ -98,6 +99,7 @@ describe('Write Concern', function () {
 
         afterEach(async function () {
           await db.dropDatabase();
+          await sleep(1000);
           await client.close();
         });
 
@@ -134,9 +136,10 @@ describe('Write Concern', function () {
           await col.createIndex({ b: -1 });
           await col.createIndex({ a: 1, b: -1 });
 
+          await sleep(1000);
+
           const listIndexesResult = col.listIndexes({ batchSize: 2 });
           const err = await listIndexesResult.toArray().catch(e => e);
-
           expect(err).to.not.be.instanceOf(Error);
         });
 
@@ -165,6 +168,8 @@ describe('Write Concern', function () {
               { writeConcern: { w: 'majority' } }
             );
 
+            await sleep(1000);
+
             const err = await changes.next().catch(e => e);
             expect(err).to.not.be.instanceOf(Error);
           }

From 7ca5e034a43522e07697915058b9928f8a364855 Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Thu, 12 Sep 2024 12:02:27 -0400
Subject: [PATCH 08/22] requested changes 1

---
 test/integration/read-write-concern/write_concern.test.ts | 8 +-------
 test/unit/commands.test.ts                                | 2 +-
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/test/integration/read-write-concern/write_concern.test.ts b/test/integration/read-write-concern/write_concern.test.ts
index 9d479a22718..64e656e4df4 100644
--- a/test/integration/read-write-concern/write_concern.test.ts
+++ b/test/integration/read-write-concern/write_concern.test.ts
@@ -13,7 +13,6 @@ import {
   OpMsgRequest
 } from '../../mongodb';
 import * as mock from '../../tools/mongodb-mock/index';
-import { sleep } from '../../tools/utils';
 import { filterForCommands } from '../shared';
 
 describe('Write Concern', function () {
@@ -98,8 +97,7 @@ describe('Write Concern', function () {
         });
 
         afterEach(async function () {
-          await db.dropDatabase();
-          await sleep(1000);
+          await db.dropDatabase({ writeConcern: { w: 'majority' } });
           await client.close();
         });
 
@@ -136,8 +134,6 @@ describe('Write Concern', function () {
           await col.createIndex({ b: -1 });
           await col.createIndex({ a: 1, b: -1 });
 
-          await sleep(1000);
-
           const listIndexesResult = col.listIndexes({ batchSize: 2 });
           const err = await listIndexesResult.toArray().catch(e => e);
           expect(err).to.not.be.instanceOf(Error);
@@ -168,8 +164,6 @@ describe('Write Concern', function () {
               { writeConcern: { w: 'majority' } }
             );
 
-            await sleep(1000);
-
             const err = await changes.next().catch(e => e);
             expect(err).to.not.be.instanceOf(Error);
           }
diff --git a/test/unit/commands.test.ts b/test/unit/commands.test.ts
index 2b2cf5f58b4..3f601c678c0 100644
--- a/test/unit/commands.test.ts
+++ b/test/unit/commands.test.ts
@@ -111,7 +111,7 @@ describe('class OpCompressedRequest', () => {
 });
 
 describe('OpMsgRequest', () => {
-  describe('fire-and-forget', () => {
+  describe('#constructor', () => {
     context('when writeConcern = 0', () => {
       it('moreToCome is set to true', async () => {
         const request = new OpMsgRequest('db', { a: 1, writeConcern: { w: 0 } }, {});

From 8243f9953e3a220a917790c23546087dfe9caeb2 Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Thu, 12 Sep 2024 17:31:59 -0400
Subject: [PATCH 09/22] remove moreToCome as an option on the request - only on
 the reply

---
 src/cmap/commands.ts | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/src/cmap/commands.ts b/src/cmap/commands.ts
index a7554ff8819..02f7fa0d7e9 100644
--- a/src/cmap/commands.ts
+++ b/src/cmap/commands.ts
@@ -50,7 +50,6 @@ export interface OpQueryOptions extends CommandOptions {
   secondaryOk?: boolean;
 
   requestId?: number;
-  moreToCome?: boolean;
   exhaustAllowed?: boolean;
 }
 
@@ -412,7 +411,6 @@ export interface OpMsgOptions {
   ignoreUndefined: boolean;
   checkKeys: boolean;
   maxBsonSize: number;
-  moreToCome: boolean;
   exhaustAllowed: boolean;
   readPreference: ReadPreference;
 }
@@ -465,7 +463,7 @@ export class OpMsgRequest {
 
     // flags
     this.checksumPresent = false;
-    this.moreToCome = options.moreToCome || command.writeConcern?.w === 0 || false;
+    this.moreToCome = command.writeConcern?.w === 0 || false;
     this.exhaustAllowed =
       typeof options.exhaustAllowed === 'boolean' ? options.exhaustAllowed : false;
   }

From 7c607fd8356190e222aedba6be32edd40e703059 Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Thu, 12 Sep 2024 17:46:37 -0400
Subject: [PATCH 10/22] add check to remove wordiness

---
 src/cmap/commands.ts                                      | 2 ++
 src/cmap/connection.ts                                    | 4 ++--
 test/integration/node-specific/mongo_client.test.ts       | 2 +-
 test/integration/read-write-concern/write_concern.test.ts | 1 +
 4 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/cmap/commands.ts b/src/cmap/commands.ts
index 02f7fa0d7e9..a613447a06f 100644
--- a/src/cmap/commands.ts
+++ b/src/cmap/commands.ts
@@ -73,6 +73,8 @@ export class OpQueryRequest {
   awaitData: boolean;
   exhaust: boolean;
   partial: boolean;
+  /** moreToCome is an OP_MSG only concept */
+  moreToCome = false;
 
   constructor(
     public databaseName: string,
diff --git a/src/cmap/connection.ts b/src/cmap/connection.ts
index c8b51528704..986cce46b6e 100644
--- a/src/cmap/connection.ts
+++ b/src/cmap/connection.ts
@@ -439,7 +439,7 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
         zlibCompressionLevel: this.description.zlibCompressionLevel
       });
 
-      if (options.noResponse || ('moreToCome' in message && message.moreToCome)) {
+      if (options.noResponse || message.moreToCome) {
         yield MongoDBResponse.empty;
         return;
       }
@@ -529,7 +529,7 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
               message,
               options.noResponse
                 ? undefined
-                : 'moreToCome' in message && message.moreToCome
+                : message.moreToCome
                   ? { ok: 1 }
                   : (object ??= document.toObject(bsonOptions)),
               started,
diff --git a/test/integration/node-specific/mongo_client.test.ts b/test/integration/node-specific/mongo_client.test.ts
index 634516f8f76..bf94cbab7d6 100644
--- a/test/integration/node-specific/mongo_client.test.ts
+++ b/test/integration/node-specific/mongo_client.test.ts
@@ -698,7 +698,7 @@ describe('class MongoClient', function () {
       expect(startedEvents).to.have.lengthOf(1);
       expect(startedEvents[0]).to.have.property('commandName', 'endSessions');
       expect(endEvents).to.have.lengthOf(1);
-      expect(endEvents[0]).to.have.property('reply', undefined); // noReponse: true
+      expect(endEvents[0]).to.containSubset({ reply: { ok: 1 } });
     });
 
     context('when server selection would return no servers', () => {
diff --git a/test/integration/read-write-concern/write_concern.test.ts b/test/integration/read-write-concern/write_concern.test.ts
index 64e656e4df4..9db7269b89f 100644
--- a/test/integration/read-write-concern/write_concern.test.ts
+++ b/test/integration/read-write-concern/write_concern.test.ts
@@ -136,6 +136,7 @@ describe('Write Concern', function () {
 
           const listIndexesResult = col.listIndexes({ batchSize: 2 });
           const err = await listIndexesResult.toArray().catch(e => e);
+
           expect(err).to.not.be.instanceOf(Error);
         });
 

From 8b59ecd10c96d10128003bca574952a4b0c8a200 Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Fri, 13 Sep 2024 10:44:20 -0400
Subject: [PATCH 11/22] remove extraneous change

---
 test/integration/node-specific/mongo_client.test.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/integration/node-specific/mongo_client.test.ts b/test/integration/node-specific/mongo_client.test.ts
index bf94cbab7d6..7ef0ecfc321 100644
--- a/test/integration/node-specific/mongo_client.test.ts
+++ b/test/integration/node-specific/mongo_client.test.ts
@@ -698,7 +698,7 @@ describe('class MongoClient', function () {
       expect(startedEvents).to.have.lengthOf(1);
       expect(startedEvents[0]).to.have.property('commandName', 'endSessions');
       expect(endEvents).to.have.lengthOf(1);
-      expect(endEvents[0]).to.containSubset({ reply: { ok: 1 } });
+      expect(endEvents[0]).to.property('reply', undefined);
     });
 
     context('when server selection would return no servers', () => {

From 6422402188bb3fd8573a96c19dda0027dacbcdae Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Fri, 13 Sep 2024 10:57:11 -0400
Subject: [PATCH 12/22] deprecate noResponse

---
 src/operations/command.ts     | 1 +
 src/operations/run_command.ts | 1 +
 2 files changed, 2 insertions(+)

diff --git a/src/operations/command.ts b/src/operations/command.ts
index 94ccc6ceafe..51a6f647e93 100644
--- a/src/operations/command.ts
+++ b/src/operations/command.ts
@@ -55,6 +55,7 @@ export interface CommandOperationOptions
   // Admin command overrides.
   dbName?: string;
   authdb?: string;
+  /** @deprecated Will be removed in the next major version. Set writeConcern.w to 0 instead. */
   noResponse?: boolean;
 }
 
diff --git a/src/operations/run_command.ts b/src/operations/run_command.ts
index ad7d02c044f..7c8abb76333 100644
--- a/src/operations/run_command.ts
+++ b/src/operations/run_command.ts
@@ -51,6 +51,7 @@ export class RunAdminCommandOperation<T = Document> extends AbstractOperation<T>
   constructor(
     public command: Document,
     public override options: RunCommandOptions & {
+      /** @deprecated Will be removed in the next major version, and replaced with an option to set writeConcern.w to 0 */
       noResponse?: boolean;
       bypassPinningCheck?: boolean;
     }

From ee93834b08ca7556b30125cce8399b11b35d9dd8 Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Fri, 13 Sep 2024 15:59:46 -0400
Subject: [PATCH 13/22] add moreToCome back on the request

---
 src/cmap/commands.ts | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/src/cmap/commands.ts b/src/cmap/commands.ts
index a613447a06f..1cc074b3b1c 100644
--- a/src/cmap/commands.ts
+++ b/src/cmap/commands.ts
@@ -50,6 +50,7 @@ export interface OpQueryOptions extends CommandOptions {
   secondaryOk?: boolean;
 
   requestId?: number;
+  moreToCome?: boolean;
   exhaustAllowed?: boolean;
 }
 
@@ -408,12 +409,21 @@ const OPTS_EXHAUST_ALLOWED = 1 << 16;
 
 /** @internal */
 export interface OpMsgOptions {
-  requestId: number;
-  serializeFunctions: boolean;
-  ignoreUndefined: boolean;
-  checkKeys: boolean;
-  maxBsonSize: number;
-  exhaustAllowed: boolean;
+  socketTimeoutMS?: number;
+  session?: ClientSession;
+  numberToSkip?: number;
+  numberToReturn?: number;
+  returnFieldSelector?: Document;
+  pre32Limit?: number;
+  serializeFunctions?: boolean;
+  ignoreUndefined?: boolean;
+  maxBsonSize?: number;
+  checkKeys?: boolean;
+  secondaryOk?: boolean;
+
+  requestId?: number;
+  moreToCome?: boolean;
+  exhaustAllowed?: boolean;
   readPreference: ReadPreference;
 }
 
@@ -465,7 +475,7 @@ export class OpMsgRequest {
 
     // flags
     this.checksumPresent = false;
-    this.moreToCome = command.writeConcern?.w === 0 || false;
+    this.moreToCome = options.moreToCome || command.writeConcern?.w === 0 || false;
     this.exhaustAllowed =
       typeof options.exhaustAllowed === 'boolean' ? options.exhaustAllowed : false;
   }

From 56772b7f72795e6564edd74c711014e8daea3377 Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Fri, 13 Sep 2024 16:07:26 -0400
Subject: [PATCH 14/22] update deprecation comment

---
 src/operations/command.ts     | 7 ++++++-
 src/operations/run_command.ts | 1 -
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/operations/command.ts b/src/operations/command.ts
index 51a6f647e93..8bfa111edfa 100644
--- a/src/operations/command.ts
+++ b/src/operations/command.ts
@@ -55,7 +55,12 @@ export interface CommandOperationOptions
   // Admin command overrides.
   dbName?: string;
   authdb?: string;
-  /** @deprecated Will be removed in the next major version. Set writeConcern.w to 0 instead. */
+  /**
+   * @deprecated
+   * Will be removed in the next major version. Set writeConcern.w to 0 instead.
+   *
+   * **WARNING:** When this flag is true, it may result in indeterminate driver behavior.
+   */
   noResponse?: boolean;
 }
 
diff --git a/src/operations/run_command.ts b/src/operations/run_command.ts
index 7c8abb76333..ad7d02c044f 100644
--- a/src/operations/run_command.ts
+++ b/src/operations/run_command.ts
@@ -51,7 +51,6 @@ export class RunAdminCommandOperation<T = Document> extends AbstractOperation<T>
   constructor(
     public command: Document,
     public override options: RunCommandOptions & {
-      /** @deprecated Will be removed in the next major version, and replaced with an option to set writeConcern.w to 0 */
       noResponse?: boolean;
       bypassPinningCheck?: boolean;
     }

From 6104c57e71a6fc4ad202f8185cde69655af8f5cb Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Mon, 16 Sep 2024 10:51:54 -0400
Subject: [PATCH 15/22] remove noResponse deprecation - do in node-6377

lint fix
---
 src/cmap/commands.ts                                | 2 +-
 src/operations/command.ts                           | 6 ------
 test/integration/node-specific/mongo_client.test.ts | 2 +-
 3 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/src/cmap/commands.ts b/src/cmap/commands.ts
index 1cc074b3b1c..73ef1f2e1f4 100644
--- a/src/cmap/commands.ts
+++ b/src/cmap/commands.ts
@@ -475,7 +475,7 @@ export class OpMsgRequest {
 
     // flags
     this.checksumPresent = false;
-    this.moreToCome = options.moreToCome || command.writeConcern?.w === 0 || false;
+    this.moreToCome = options.moreToCome ?? command.writeConcern?.w === 0;
     this.exhaustAllowed =
       typeof options.exhaustAllowed === 'boolean' ? options.exhaustAllowed : false;
   }
diff --git a/src/operations/command.ts b/src/operations/command.ts
index 8bfa111edfa..94ccc6ceafe 100644
--- a/src/operations/command.ts
+++ b/src/operations/command.ts
@@ -55,12 +55,6 @@ export interface CommandOperationOptions
   // Admin command overrides.
   dbName?: string;
   authdb?: string;
-  /**
-   * @deprecated
-   * Will be removed in the next major version. Set writeConcern.w to 0 instead.
-   *
-   * **WARNING:** When this flag is true, it may result in indeterminate driver behavior.
-   */
   noResponse?: boolean;
 }
 
diff --git a/test/integration/node-specific/mongo_client.test.ts b/test/integration/node-specific/mongo_client.test.ts
index 7ef0ecfc321..634516f8f76 100644
--- a/test/integration/node-specific/mongo_client.test.ts
+++ b/test/integration/node-specific/mongo_client.test.ts
@@ -698,7 +698,7 @@ describe('class MongoClient', function () {
       expect(startedEvents).to.have.lengthOf(1);
       expect(startedEvents[0]).to.have.property('commandName', 'endSessions');
       expect(endEvents).to.have.lengthOf(1);
-      expect(endEvents[0]).to.property('reply', undefined);
+      expect(endEvents[0]).to.have.property('reply', undefined); // noReponse: true
     });
 
     context('when server selection would return no servers', () => {

From 419a84843b888122cd7c8ced41f4cf7d8d057205 Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Mon, 16 Sep 2024 11:30:19 -0400
Subject: [PATCH 16/22] fix(NODE-6377): Remove noResponse option

temp

temp2
---
 src/cmap/connection.ts                        | 12 ++++------
 src/mongo_client.ts                           |  2 +-
 src/operations/command.ts                     |  1 -
 src/operations/run_command.ts                 |  7 +++---
 .../connection.test.ts                        | 15 ++++++++++++
 .../node-specific/mongo_client.test.ts        |  4 ++--
 test/unit/cmap/connection.test.ts             | 23 -------------------
 7 files changed, 27 insertions(+), 37 deletions(-)

diff --git a/src/cmap/connection.ts b/src/cmap/connection.ts
index 986cce46b6e..4bcb4850e5c 100644
--- a/src/cmap/connection.ts
+++ b/src/cmap/connection.ts
@@ -81,7 +81,6 @@ export interface CommandOptions extends BSONSerializeOptions {
   /** Session to use for the operation */
   session?: ClientSession;
   documentsReturnedIn?: string;
-  noResponse?: boolean;
   omitReadPreference?: boolean;
 
   // TODO(NODE-2802): Currently the CommandOptions take a property willRetryWrite which is a hint
@@ -94,6 +93,9 @@ export interface CommandOptions extends BSONSerializeOptions {
   writeConcern?: WriteConcern;
 
   directConnection?: boolean;
+
+  // Triggers fire-and-forget protocol for commands that don't support WriteConcern
+  moreToCome?: boolean;
 }
 
 /** @public */
@@ -439,7 +441,7 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
         zlibCompressionLevel: this.description.zlibCompressionLevel
       });
 
-      if (options.noResponse || message.moreToCome) {
+      if (message.moreToCome) {
         yield MongoDBResponse.empty;
         return;
       }
@@ -527,11 +529,7 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
             new CommandSucceededEvent(
               this,
               message,
-              options.noResponse
-                ? undefined
-                : message.moreToCome
-                  ? { ok: 1 }
-                  : (object ??= document.toObject(bsonOptions)),
+              message.moreToCome ? { ok: 1 } : (object ??= document.toObject(bsonOptions)),
               started,
               this.description.serverConnectionId
             )
diff --git a/src/mongo_client.ts b/src/mongo_client.ts
index e8aae516392..c2c42c0318b 100644
--- a/src/mongo_client.ts
+++ b/src/mongo_client.ts
@@ -628,7 +628,7 @@ export class MongoClient extends TypedEventEmitter<MongoClientEvents> implements
             this,
             new RunAdminCommandOperation(
               { endSessions },
-              { readPreference: ReadPreference.primaryPreferred, noResponse: true }
+              { readPreference: ReadPreference.primaryPreferred, moreToCome: true }
             )
           );
         } catch (error) {
diff --git a/src/operations/command.ts b/src/operations/command.ts
index 94ccc6ceafe..3786753bc6e 100644
--- a/src/operations/command.ts
+++ b/src/operations/command.ts
@@ -55,7 +55,6 @@ export interface CommandOperationOptions
   // Admin command overrides.
   dbName?: string;
   authdb?: string;
-  noResponse?: boolean;
 }
 
 /** @internal */
diff --git a/src/operations/run_command.ts b/src/operations/run_command.ts
index ad7d02c044f..ae24a9a6dfd 100644
--- a/src/operations/run_command.ts
+++ b/src/operations/run_command.ts
@@ -5,8 +5,9 @@ import { type TODO_NODE_3286 } from '../mongo_types';
 import type { ReadPreferenceLike } from '../read_preference';
 import type { Server } from '../sdam/server';
 import type { ClientSession } from '../sessions';
+import type { WriteConcern } from '../write_concern';
 import { MongoDBNamespace } from '../utils';
-import { AbstractOperation } from './operation';
+import { Aspect, defineAspects, AbstractOperation } from './operation';
 
 /** @public */
 export type RunCommandOptions = {
@@ -51,7 +52,7 @@ export class RunAdminCommandOperation<T = Document> extends AbstractOperation<T>
   constructor(
     public command: Document,
     public override options: RunCommandOptions & {
-      noResponse?: boolean;
+      moreToCome?: boolean;
       bypassPinningCheck?: boolean;
     }
   ) {
@@ -72,4 +73,4 @@ export class RunAdminCommandOperation<T = Document> extends AbstractOperation<T>
     });
     return res;
   }
-}
+}
\ No newline at end of file
diff --git a/test/integration/connection-monitoring-and-pooling/connection.test.ts b/test/integration/connection-monitoring-and-pooling/connection.test.ts
index 1192dfdbcd4..e0b21c2f54b 100644
--- a/test/integration/connection-monitoring-and-pooling/connection.test.ts
+++ b/test/integration/connection-monitoring-and-pooling/connection.test.ts
@@ -144,6 +144,21 @@ describe('Connection', function () {
         }
       }
     });
+
+    it('supports fire-and-forget messages', async function () {
+      const options: ConnectionOptions = {
+        ...commonConnectOptions,
+        connectionType: Connection,
+        ...this.configuration.options,
+        metadata: makeClientMetadata({ driverInfo: {} }),
+        extendedMetadata: addContainerMetadata(makeClientMetadata({ driverInfo: {} }))
+      };
+
+      const conn = await connect(options);
+      const readSpy = sinon.spy(conn, 'readMany');
+      await conn.command(ns('$admin.cmd'), { ping: 1 }, { moreToCome: true });
+      expect(readSpy).to.not.have.been.called;
+    });
   });
 
   describe('Connection - functional', function () {
diff --git a/test/integration/node-specific/mongo_client.test.ts b/test/integration/node-specific/mongo_client.test.ts
index 634516f8f76..7d853e21007 100644
--- a/test/integration/node-specific/mongo_client.test.ts
+++ b/test/integration/node-specific/mongo_client.test.ts
@@ -682,7 +682,7 @@ describe('class MongoClient', function () {
       expect(result2).to.have.property('ok', 1);
     });
 
-    it('sends endSessions with noResponse set', async () => {
+    it('sends endSessions with writeConcern w = 0 set', async () => {
       const session = client.startSession(); // make a session to be ended
       await client.db('test').command({ ping: 1 }, { session });
       await session.endSession();
@@ -698,7 +698,7 @@ describe('class MongoClient', function () {
       expect(startedEvents).to.have.lengthOf(1);
       expect(startedEvents[0]).to.have.property('commandName', 'endSessions');
       expect(endEvents).to.have.lengthOf(1);
-      expect(endEvents[0]).to.have.property('reply', undefined); // noReponse: true
+      expect(endEvents[0]).to.containSubset({ reply: { ok: 1 } }); // writeConcern.w = 0
     });
 
     context('when server selection would return no servers', () => {
diff --git a/test/unit/cmap/connection.test.ts b/test/unit/cmap/connection.test.ts
index 75d5c246f24..639de5a0817 100644
--- a/test/unit/cmap/connection.test.ts
+++ b/test/unit/cmap/connection.test.ts
@@ -28,29 +28,6 @@ describe('new Connection()', function () {
 
   before(() => mock.createServer().then(s => (server = s)));
 
-  it('supports fire-and-forget messages', async function () {
-    server.setMessageHandler(request => {
-      const doc = request.document;
-      if (isHello(doc)) {
-        request.reply(mock.HELLO);
-      }
-
-      // black hole all other requests
-    });
-
-    const options = {
-      ...connectionOptionsDefaults,
-      connectionType: Connection,
-      hostAddress: server.hostAddress(),
-      authProviders: new MongoClientAuthProviders()
-    };
-
-    const conn = await connect(options);
-    const readSpy = sinon.spy(conn, 'readMany');
-    await conn.command(ns('$admin.cmd'), { ping: 1 }, { noResponse: true });
-    expect(readSpy).to.not.have.been.called;
-  });
-
   it('destroys streams which time out', async function () {
     server.setMessageHandler(request => {
       const doc = request.document;

From 4a94e4e458dfc255c878b4ba74f5d0942760d808 Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Mon, 16 Sep 2024 16:21:42 -0400
Subject: [PATCH 17/22] lint fix

---
 src/operations/run_command.ts | 5 ++---
 test/unit/collection.test.ts  | 2 +-
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/operations/run_command.ts b/src/operations/run_command.ts
index ae24a9a6dfd..289bfed18dd 100644
--- a/src/operations/run_command.ts
+++ b/src/operations/run_command.ts
@@ -5,9 +5,8 @@ import { type TODO_NODE_3286 } from '../mongo_types';
 import type { ReadPreferenceLike } from '../read_preference';
 import type { Server } from '../sdam/server';
 import type { ClientSession } from '../sessions';
-import type { WriteConcern } from '../write_concern';
 import { MongoDBNamespace } from '../utils';
-import { Aspect, defineAspects, AbstractOperation } from './operation';
+import { AbstractOperation } from './operation';
 
 /** @public */
 export type RunCommandOptions = {
@@ -73,4 +72,4 @@ export class RunAdminCommandOperation<T = Document> extends AbstractOperation<T>
     });
     return res;
   }
-}
\ No newline at end of file
+}
diff --git a/test/unit/collection.test.ts b/test/unit/collection.test.ts
index b050e69dc92..a6f40e7783b 100644
--- a/test/unit/collection.test.ts
+++ b/test/unit/collection.test.ts
@@ -15,7 +15,7 @@ describe('Collection', function () {
   });
 
   context('#createIndex', () => {
-    it('should error when createIndex fails', function (done) {
+    it.only('should error when createIndex fails', function (done) {
       const ERROR_RESPONSE = {
         ok: 0,
         errmsg:

From 3787250c7624aa0ac5b33bd36c3e48e137befcee Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Thu, 19 Sep 2024 18:11:11 -0400
Subject: [PATCH 18/22] move unit to integration test to get correct
 maxWireVersion for opMsg

---
 .../collection-management/collection.test.ts  | 46 ++++++++++++++++-
 test/unit/collection.test.ts                  | 49 -------------------
 2 files changed, 44 insertions(+), 51 deletions(-)

diff --git a/test/integration/collection-management/collection.test.ts b/test/integration/collection-management/collection.test.ts
index 809b4697dea..b099a812fc5 100644
--- a/test/integration/collection-management/collection.test.ts
+++ b/test/integration/collection-management/collection.test.ts
@@ -1,6 +1,13 @@
 import { expect } from 'chai';
-
-import { Collection, type Db, type MongoClient, MongoServerError } from '../../mongodb';
+import * as sinon from 'sinon';
+
+import {
+  Collection,
+  CreateIndexesOperation,
+  type Db,
+  type MongoClient,
+  MongoServerError
+} from '../../mongodb';
 import { type FailPoint } from '../../tools/utils';
 import { setupDatabase } from '../shared';
 
@@ -422,6 +429,41 @@ describe('Collection', function () {
     });
   });
 
+  describe('#createIndex', () => {
+    let client: MongoClient;
+    let db: Db;
+    let coll: Collection<{ a: string }>;
+    const ERROR_RESPONSE = {
+      ok: 0,
+      errmsg:
+        'WiredTigerIndex::insert: key too large to index, failing  1470 { : "56f37cb8e4b089e98d52ab0e", : "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa..." }',
+      code: 17280
+    };
+
+    beforeEach(async function () {
+      client = configuration.newClient({ w: 1 });
+      db = client.db(configuration.db);
+      coll = db.collection('test_coll');
+      await client.connect();
+      sinon.stub(CreateIndexesOperation.prototype, 'execute').callsFake(() => {
+        throw ERROR_RESPONSE;
+      });
+    });
+
+    afterEach(async function () {
+      await coll.drop();
+      await client.close();
+      sinon.restore();
+    });
+
+    it('should error when createIndex fails', async function () {
+      const e = await coll.createIndex({ a: 1 }).catch(e => e);
+      expect(e).to.have.property('ok', ERROR_RESPONSE.ok);
+      expect(e).to.have.property('errmsg', ERROR_RESPONSE.errmsg);
+      expect(e).to.have.property('code', ERROR_RESPONSE.code);
+    });
+  });
+
   describe('countDocuments()', function () {
     let client: MongoClient;
     let collection: Collection<{ test: string }>;
diff --git a/test/unit/collection.test.ts b/test/unit/collection.test.ts
index a6f40e7783b..c45712abebc 100644
--- a/test/unit/collection.test.ts
+++ b/test/unit/collection.test.ts
@@ -14,55 +14,6 @@ describe('Collection', function () {
     await cleanup();
   });
 
-  context('#createIndex', () => {
-    it.only('should error when createIndex fails', function (done) {
-      const ERROR_RESPONSE = {
-        ok: 0,
-        errmsg:
-          'WiredTigerIndex::insert: key too large to index, failing  1470 { : "56f37cb8e4b089e98d52ab0e", : "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa..." }',
-        code: 17280
-      };
-
-      server.setMessageHandler(request => {
-        const doc = request.document;
-
-        if (isHello(doc)) {
-          return request.reply(Object.assign({}, HELLO));
-        }
-
-        if (doc.createIndexes) {
-          return request.reply(ERROR_RESPONSE);
-        }
-
-        if (doc.insert === 'system.indexes') {
-          return request.reply(ERROR_RESPONSE);
-        }
-      });
-
-      const client = new MongoClient(`mongodb://${server.uri()}`);
-
-      const close = e => client.close().then(() => done(e));
-
-      client
-        .connect()
-        .then(() => client.db('foo').collection('bar'))
-        .then(coll => coll.createIndex({ a: 1 }))
-        .then(
-          () => close('Expected createIndex to fail, but it succeeded'),
-          e => {
-            try {
-              expect(e).to.have.property('ok', ERROR_RESPONSE.ok);
-              expect(e).to.have.property('errmsg', ERROR_RESPONSE.errmsg);
-              expect(e).to.have.property('code', ERROR_RESPONSE.code);
-              close(null);
-            } catch (err) {
-              close(err);
-            }
-          }
-        );
-    });
-  });
-
   context('#aggregate', () => {
     // general test for aggregate function
     function testAggregate(config, done) {

From 4eb7c120213d5774553360e6e0f6d0c8e14629d0 Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Tue, 24 Sep 2024 17:08:58 -0400
Subject: [PATCH 19/22] requested changes team review

---
 src/cmap/connection.ts                              | 2 +-
 test/integration/node-specific/mongo_client.test.ts | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/cmap/connection.ts b/src/cmap/connection.ts
index 4bcb4850e5c..6b8ed3f458a 100644
--- a/src/cmap/connection.ts
+++ b/src/cmap/connection.ts
@@ -94,7 +94,7 @@ export interface CommandOptions extends BSONSerializeOptions {
 
   directConnection?: boolean;
 
-  // Triggers fire-and-forget protocol for commands that don't support WriteConcern
+  /** Triggers fire-and-forget protocol for commands that don't support WriteConcern */
   moreToCome?: boolean;
 }
 
diff --git a/test/integration/node-specific/mongo_client.test.ts b/test/integration/node-specific/mongo_client.test.ts
index 7d853e21007..7d3f901fb57 100644
--- a/test/integration/node-specific/mongo_client.test.ts
+++ b/test/integration/node-specific/mongo_client.test.ts
@@ -698,7 +698,7 @@ describe('class MongoClient', function () {
       expect(startedEvents).to.have.lengthOf(1);
       expect(startedEvents[0]).to.have.property('commandName', 'endSessions');
       expect(endEvents).to.have.lengthOf(1);
-      expect(endEvents[0]).to.containSubset({ reply: { ok: 1 } }); // writeConcern.w = 0
+      expect(endEvents[0]).to.containSubset({ reply: { ok: 1 } }); // moreToCome = true
     });
 
     context('when server selection would return no servers', () => {

From b133f86e742aa6bc495fc243fd40f14c669a2e1f Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Wed, 25 Sep 2024 16:48:40 -0400
Subject: [PATCH 20/22] fix failing tests

---
 .../collection-management/collection.test.ts  |  1 -
 .../connection.test.ts                        | 29 ++++++++++---------
 2 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/test/integration/collection-management/collection.test.ts b/test/integration/collection-management/collection.test.ts
index b099a812fc5..d73a1f229a4 100644
--- a/test/integration/collection-management/collection.test.ts
+++ b/test/integration/collection-management/collection.test.ts
@@ -451,7 +451,6 @@ describe('Collection', function () {
     });
 
     afterEach(async function () {
-      await coll.drop();
       await client.close();
       sinon.restore();
     });
diff --git a/test/integration/connection-monitoring-and-pooling/connection.test.ts b/test/integration/connection-monitoring-and-pooling/connection.test.ts
index e0b21c2f54b..6ea2ce04135 100644
--- a/test/integration/connection-monitoring-and-pooling/connection.test.ts
+++ b/test/integration/connection-monitoring-and-pooling/connection.test.ts
@@ -145,19 +145,22 @@ describe('Connection', function () {
       }
     });
 
-    it('supports fire-and-forget messages', async function () {
-      const options: ConnectionOptions = {
-        ...commonConnectOptions,
-        connectionType: Connection,
-        ...this.configuration.options,
-        metadata: makeClientMetadata({ driverInfo: {} }),
-        extendedMetadata: addContainerMetadata(makeClientMetadata({ driverInfo: {} }))
-      };
-
-      const conn = await connect(options);
-      const readSpy = sinon.spy(conn, 'readMany');
-      await conn.command(ns('$admin.cmd'), { ping: 1 }, { moreToCome: true });
-      expect(readSpy).to.not.have.been.called;
+    it('supports fire-and-forget messages', {
+      metadata: { requires: { apiVersion: false, topology: '!load-balanced' } },
+      test: async function () {
+        const options: ConnectionOptions = {
+          ...commonConnectOptions,
+          connectionType: Connection,
+          ...this.configuration.options,
+          metadata: makeClientMetadata({ driverInfo: {} }),
+          extendedMetadata: addContainerMetadata(makeClientMetadata({ driverInfo: {} }))
+        };
+
+        const conn = await connect(options);
+        const readSpy = sinon.spy(conn, 'readMany');
+        await conn.command(ns('$admin.cmd'), { ping: 1 }, { moreToCome: true });
+        expect(readSpy).to.not.have.been.called;
+      }
     });
   });
 

From 29d8330e86c29060cc98315f8a0a420df211bf97 Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Thu, 26 Sep 2024 16:19:09 -0400
Subject: [PATCH 21/22] fix test

---
 .../connection-monitoring-and-pooling/connection.test.ts         | 1 +
 1 file changed, 1 insertion(+)

diff --git a/test/integration/connection-monitoring-and-pooling/connection.test.ts b/test/integration/connection-monitoring-and-pooling/connection.test.ts
index 6ea2ce04135..02693e07804 100644
--- a/test/integration/connection-monitoring-and-pooling/connection.test.ts
+++ b/test/integration/connection-monitoring-and-pooling/connection.test.ts
@@ -160,6 +160,7 @@ describe('Connection', function () {
         const readSpy = sinon.spy(conn, 'readMany');
         await conn.command(ns('$admin.cmd'), { ping: 1 }, { moreToCome: true });
         expect(readSpy).to.not.have.been.called;
+        conn?.destroy();
       }
     });
   });

From b4b0866dc2315c2a7834bd15ba36df9dd2057ae2 Mon Sep 17 00:00:00 2001
From: Aditi Khare <aditi.khare@mongodb.com>
Date: Fri, 27 Sep 2024 05:32:04 -0400
Subject: [PATCH 22/22] fix failing noauth tests

---
 .../connection-monitoring-and-pooling/connection.test.ts        | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/integration/connection-monitoring-and-pooling/connection.test.ts b/test/integration/connection-monitoring-and-pooling/connection.test.ts
index 02693e07804..78433f0665e 100644
--- a/test/integration/connection-monitoring-and-pooling/connection.test.ts
+++ b/test/integration/connection-monitoring-and-pooling/connection.test.ts
@@ -297,8 +297,8 @@ describe('Connection', function () {
         });
 
         afterEach(async function () {
-          await client.close();
           mockServer.destroy();
+          await client.close();
           sinon.restore();
         });