From d588ada62d9fa91ca8eeb76b3a29aa68a3f2d824 Mon Sep 17 00:00:00 2001
From: Neal Beeken <neal.beeken@mongodb.com>
Date: Thu, 2 Jan 2025 10:33:08 -0500
Subject: [PATCH 01/17] refactor(NODE-6616): short circuit EJSON stringifying

---
 src/mongo_logger.ts | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/mongo_logger.ts b/src/mongo_logger.ts
index f83c16138ff..d49bbe6071a 100644
--- a/src/mongo_logger.ts
+++ b/src/mongo_logger.ts
@@ -1,4 +1,5 @@
 import { inspect, promisify } from 'util';
+import { isUint8Array } from 'util/types';
 
 import { type Document, EJSON, type EJSONOptions, type ObjectId } from './bson';
 import type { CommandStartedEvent } from './cmap/command_monitoring_events';
@@ -421,13 +422,44 @@ export function stringifyWithMaxLen(
 ): string {
   let strToTruncate = '';
 
+  let currentLength = 0;
+  const maxDocumentLengthEnsurer = function maxDocumentLengthEnsurer(key: string, value: any) {
+    if (currentLength >= maxDocumentLength) {
+      return undefined;
+    }
+
+    currentLength += key.length + 4;
+
+    if (typeof value === 'string') {
+      currentLength += value.length;
+    } else if (typeof value === 'number' || typeof value === 'bigint') {
+      currentLength += 20;
+    } else if (typeof value === 'boolean') {
+      currentLength += value ? 4 : 5;
+    } else if (value != null && typeof value === 'object' && '_bsontype' in value) {
+      if (isUint8Array(value.buffer)) {
+        currentLength += (value.buffer.byteLength + value.buffer.byteLength * 0.5) | 0;
+      } else if (value._bsontype === 'Binary') {
+        currentLength += (value.position + value.position * 0.3) | 0;
+      } else if (value._bsontype === 'Code') {
+        currentLength += value.code.length;
+      }
+    }
+
+    return value;
+  };
+
   if (typeof value === 'string') {
     strToTruncate = value;
   } else if (typeof value === 'function') {
     strToTruncate = value.name;
   } else {
     try {
-      strToTruncate = EJSON.stringify(value, options);
+      if (maxDocumentLength !== 0) {
+        strToTruncate = EJSON.stringify(value, maxDocumentLengthEnsurer, 0, options);
+      } else {
+        strToTruncate = EJSON.stringify(value, options);
+      }
     } catch (e) {
       strToTruncate = `Extended JSON serialization failed with: ${e.message}`;
     }

From a4cce5fef496eadec558d84a4d759f1defdbd556 Mon Sep 17 00:00:00 2001
From: Durran Jordan <durran@gmail.com>
Date: Fri, 17 Jan 2025 16:16:02 +0100
Subject: [PATCH 02/17] chore(NODE-6637): remove drivers tools env setting
 (#4363)

---
 .evergreen/config.yml                  | 54 --------------------------
 .evergreen/generate_evergreen_tasks.js |  2 +-
 .evergreen/install-dependencies.sh     | 14 +------
 3 files changed, 3 insertions(+), 67 deletions(-)

diff --git a/.evergreen/config.yml b/.evergreen/config.yml
index a3dbad1e7a3..828e804f6f9 100644
--- a/.evergreen/config.yml
+++ b/.evergreen/config.yml
@@ -1383,7 +1383,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: latest}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: auth}
@@ -1400,7 +1399,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: latest}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: auth}
@@ -1417,7 +1415,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: latest}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: auth}
@@ -1434,7 +1431,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: rapid}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: auth}
@@ -1451,7 +1447,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: rapid}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: auth}
@@ -1468,7 +1463,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: rapid}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: auth}
@@ -1485,7 +1479,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '8.0'}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: auth}
@@ -1502,7 +1495,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '8.0'}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: auth}
@@ -1519,7 +1511,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '8.0'}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: auth}
@@ -1536,7 +1527,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '7.0'}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: auth}
@@ -1553,7 +1543,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '7.0'}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: auth}
@@ -1570,7 +1559,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '7.0'}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: auth}
@@ -1587,7 +1575,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '6.0'}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: auth}
@@ -1604,7 +1591,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '6.0'}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: auth}
@@ -1621,7 +1607,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '6.0'}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: auth}
@@ -1638,7 +1623,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '5.0'}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: auth}
@@ -1655,7 +1639,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '5.0'}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: auth}
@@ -1672,7 +1655,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '5.0'}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: auth}
@@ -1689,7 +1671,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.4'}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: auth}
@@ -1706,7 +1687,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.4'}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: auth}
@@ -1723,7 +1703,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.4'}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: auth}
@@ -1740,7 +1719,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.2'}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: auth}
@@ -1757,7 +1735,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.2'}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: auth}
@@ -1774,7 +1751,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.2'}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: auth}
@@ -1791,7 +1767,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.0'}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: auth}
@@ -1808,7 +1783,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.0'}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: auth}
@@ -1825,7 +1799,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.0'}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: auth}
@@ -3860,7 +3833,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: latest}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: noauth}
@@ -3878,7 +3850,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: latest}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: noauth}
@@ -3896,7 +3867,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: latest}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: noauth}
@@ -3914,7 +3884,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: rapid}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: noauth}
@@ -3932,7 +3901,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: rapid}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: noauth}
@@ -3950,7 +3918,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: rapid}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: noauth}
@@ -3968,7 +3935,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '8.0'}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: noauth}
@@ -3986,7 +3952,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '8.0'}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: noauth}
@@ -4004,7 +3969,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '8.0'}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: noauth}
@@ -4022,7 +3986,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '7.0'}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: noauth}
@@ -4040,7 +4003,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '7.0'}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: noauth}
@@ -4058,7 +4020,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '7.0'}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: noauth}
@@ -4076,7 +4037,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '6.0'}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: noauth}
@@ -4094,7 +4054,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '6.0'}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: noauth}
@@ -4112,7 +4071,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '6.0'}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: noauth}
@@ -4130,7 +4088,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '5.0'}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: noauth}
@@ -4148,7 +4105,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '5.0'}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: noauth}
@@ -4166,7 +4122,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '5.0'}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: noauth}
@@ -4184,7 +4139,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.4'}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: noauth}
@@ -4202,7 +4156,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.4'}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: noauth}
@@ -4220,7 +4173,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.4'}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: noauth}
@@ -4238,7 +4190,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.2'}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: noauth}
@@ -4256,7 +4207,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.2'}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: noauth}
@@ -4274,7 +4224,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.2'}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: noauth}
@@ -4292,7 +4241,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.0'}
             - {key: TOPOLOGY, value: server}
             - {key: AUTH, value: noauth}
@@ -4310,7 +4258,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.0'}
             - {key: TOPOLOGY, value: replica_set}
             - {key: AUTH, value: noauth}
@@ -4328,7 +4275,6 @@ tasks:
         type: setup
         params:
           updates:
-            - {key: NPM_VERSION, value: '9'}
             - {key: VERSION, value: '4.0'}
             - {key: TOPOLOGY, value: sharded_cluster}
             - {key: AUTH, value: noauth}
diff --git a/.evergreen/generate_evergreen_tasks.js b/.evergreen/generate_evergreen_tasks.js
index ca11d5ff61e..516e84644a0 100644
--- a/.evergreen/generate_evergreen_tasks.js
+++ b/.evergreen/generate_evergreen_tasks.js
@@ -70,7 +70,7 @@ function makeTask({ mongoVersion, topology, tags = [], auth = 'auth' }) {
     name: `test-${mongoVersion}-${topology}${auth === 'noauth' ? '-noauth' : ''}`,
     tags: [mongoVersion, topology, ...tags],
     commands: [
-      updateExpansions({ NPM_VERSION: 9, VERSION: mongoVersion, TOPOLOGY: topology, AUTH: auth }),
+      updateExpansions({ VERSION: mongoVersion, TOPOLOGY: topology, AUTH: auth }),
       { func: 'install dependencies' },
       { func: 'bootstrap mongo-orchestration' },
       { func: 'bootstrap kms servers' },
diff --git a/.evergreen/install-dependencies.sh b/.evergreen/install-dependencies.sh
index 99b4d376d4c..33b9958b885 100644
--- a/.evergreen/install-dependencies.sh
+++ b/.evergreen/install-dependencies.sh
@@ -7,18 +7,8 @@ set -o errexit  # Exit the script with error if any of the commands fail
 ## a full nodejs version, in the format v<major>.<minor>.patch
 export NODE_LTS_VERSION=${NODE_LTS_VERSION:-16}
 # npm version can be defined in the environment for cases where we need to install
-# a version lower than latest to support EOL Node versions.
-
-# If NODE_LTS_VERSION is numeric and less than 18, default to 9, if less than 20, default to 10.
-# Do not override if it is already set.
-if [[ "$NODE_LTS_VERSION" =~ ^[0-9]+$ && "$NODE_LTS_VERSION" -lt 18 ]]; then
-    export NPM_VERSION=${NPM_VERSION:-9}
-elif [[ "$NODE_LTS_VERSION" =~ ^[0-9]+$ && "$NODE_LTS_VERSION" -lt 20 ]]; then
-    export NPM_VERSION=${NPM_VERSION:-10}
-else
-    export NPM_VERSION=${NPM_VERSION:-latest}
-fi
-
+# a version lower than latest to support EOL Node versions. When not provided will
+# be handled by this script in drivers tools.
 source $DRIVERS_TOOLS/.evergreen/install-node.sh
 
 npm install "${NPM_OPTIONS}"

From d21c4ffb1b43835d0936c1a506e8f39f61dd226c Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Fri, 17 Jan 2025 18:16:50 -0500
Subject: [PATCH 03/17] perf(NODE-6452): Optimize CommandStartedEvent and
 CommandSucceededEvent constructors (#4371)

---
 src/cmap/command_monitoring_events.ts         | 65 +++----------------
 src/utils.ts                                  | 37 -----------
 .../command_monitoring.test.ts                | 45 -------------
 3 files changed, 10 insertions(+), 137 deletions(-)

diff --git a/src/cmap/command_monitoring_events.ts b/src/cmap/command_monitoring_events.ts
index a7e1653becc..992b9dc47c9 100644
--- a/src/cmap/command_monitoring_events.ts
+++ b/src/cmap/command_monitoring_events.ts
@@ -6,7 +6,7 @@ import {
   LEGACY_HELLO_COMMAND,
   LEGACY_HELLO_COMMAND_CAMEL_CASE
 } from '../constants';
-import { calculateDurationInMs, deepCopy } from '../utils';
+import { calculateDurationInMs } from '../utils';
 import {
   DocumentSequence,
   OpMsgRequest,
@@ -125,7 +125,7 @@ export class CommandSucceededEvent {
     this.requestId = command.requestId;
     this.commandName = commandName;
     this.duration = calculateDurationInMs(started);
-    this.reply = maybeRedact(commandName, cmd, extractReply(command, reply));
+    this.reply = maybeRedact(commandName, cmd, extractReply(reply));
     this.serverConnectionId = serverConnectionId;
   }
 
@@ -214,7 +214,6 @@ const HELLO_COMMANDS = new Set(['hello', LEGACY_HELLO_COMMAND, LEGACY_HELLO_COMM
 
 // helper methods
 const extractCommandName = (commandDoc: Document) => Object.keys(commandDoc)[0];
-const namespace = (command: OpQueryRequest) => command.ns;
 const collectionName = (command: OpQueryRequest) => command.ns.split('.')[1];
 const maybeRedact = (commandName: string, commandDoc: Document, result: Error | Document) =>
   SENSITIVE_COMMANDS.has(commandName) ||
@@ -242,19 +241,10 @@ const LEGACY_FIND_OPTIONS_MAP = {
   returnFieldSelector: 'projection'
 } as const;
 
-const OP_QUERY_KEYS = [
-  'tailable',
-  'oplogReplay',
-  'noCursorTimeout',
-  'awaitData',
-  'partial',
-  'exhaust'
-] as const;
-
 /** Extract the actual command from the query, possibly up-converting if it's a legacy format */
 function extractCommand(command: WriteProtocolMessageType): Document {
   if (command instanceof OpMsgRequest) {
-    const cmd = deepCopy(command.command);
+    const cmd = { ...command.command };
     // For OP_MSG with payload type 1 we need to pull the documents
     // array out of the document sequence for monitoring.
     if (cmd.ops instanceof DocumentSequence) {
@@ -276,7 +266,7 @@ function extractCommand(command: WriteProtocolMessageType): Document {
       result = { find: collectionName(command) };
       Object.keys(LEGACY_FIND_QUERY_MAP).forEach(key => {
         if (command.query[key] != null) {
-          result[LEGACY_FIND_QUERY_MAP[key]] = deepCopy(command.query[key]);
+          result[LEGACY_FIND_QUERY_MAP[key]] = { ...command.query[key] };
         }
       });
     }
@@ -284,64 +274,29 @@ function extractCommand(command: WriteProtocolMessageType): Document {
     Object.keys(LEGACY_FIND_OPTIONS_MAP).forEach(key => {
       const legacyKey = key as keyof typeof LEGACY_FIND_OPTIONS_MAP;
       if (command[legacyKey] != null) {
-        result[LEGACY_FIND_OPTIONS_MAP[legacyKey]] = deepCopy(command[legacyKey]);
-      }
-    });
-
-    OP_QUERY_KEYS.forEach(key => {
-      if (command[key]) {
-        result[key] = command[key];
+        result[LEGACY_FIND_OPTIONS_MAP[legacyKey]] = command[legacyKey];
       }
     });
 
-    if (command.pre32Limit != null) {
-      result.limit = command.pre32Limit;
-    }
-
-    if (command.query.$explain) {
-      return { explain: result };
-    }
     return result;
   }
 
-  const clonedQuery: Record<string, unknown> = {};
-  const clonedCommand: Record<string, unknown> = {};
+  let clonedQuery: Record<string, unknown> = {};
+  const clonedCommand: Record<string, unknown> = { ...command };
   if (command.query) {
-    for (const k in command.query) {
-      clonedQuery[k] = deepCopy(command.query[k]);
-    }
+    clonedQuery = { ...command.query };
     clonedCommand.query = clonedQuery;
   }
 
-  for (const k in command) {
-    if (k === 'query') continue;
-    clonedCommand[k] = deepCopy((command as unknown as Record<string, unknown>)[k]);
-  }
   return command.query ? clonedQuery : clonedCommand;
 }
 
-function extractReply(command: WriteProtocolMessageType, reply?: Document) {
+function extractReply(reply?: Document) {
   if (!reply) {
     return reply;
   }
 
-  if (command instanceof OpMsgRequest) {
-    return deepCopy(reply.result ? reply.result : reply);
-  }
-
-  // is this a legacy find command?
-  if (command.query && command.query.$query != null) {
-    return {
-      ok: 1,
-      cursor: {
-        id: deepCopy(reply.cursorId),
-        ns: namespace(command),
-        firstBatch: deepCopy(reply.documents)
-      }
-    };
-  }
-
-  return deepCopy(reply.result ? reply.result : reply);
+  return reply.result ? reply.result : reply;
 }
 
 function extractConnectionDetails(connection: Connection) {
diff --git a/src/utils.ts b/src/utils.ts
index c23161612a8..55cf455676b 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -620,43 +620,6 @@ export function isRecord(
   return true;
 }
 
-/**
- * Make a deep copy of an object
- *
- * NOTE: This is not meant to be the perfect implementation of a deep copy,
- * but instead something that is good enough for the purposes of
- * command monitoring.
- */
-export function deepCopy<T>(value: T): T {
-  if (value == null) {
-    return value;
-  } else if (Array.isArray(value)) {
-    return value.map(item => deepCopy(item)) as unknown as T;
-  } else if (isRecord(value)) {
-    const res = {} as any;
-    for (const key in value) {
-      res[key] = deepCopy(value[key]);
-    }
-    return res;
-  }
-
-  const ctor = (value as any).constructor;
-  if (ctor) {
-    switch (ctor.name.toLowerCase()) {
-      case 'date':
-        return new ctor(Number(value));
-      case 'map':
-        return new Map(value as any) as unknown as T;
-      case 'set':
-        return new Set(value as any) as unknown as T;
-      case 'buffer':
-        return Buffer.from(value as unknown as Buffer) as unknown as T;
-    }
-  }
-
-  return value;
-}
-
 type ListNode<T> = {
   value: T;
   next: ListNode<T> | HeadNode<T>;
diff --git a/test/integration/command-logging-and-monitoring/command_monitoring.test.ts b/test/integration/command-logging-and-monitoring/command_monitoring.test.ts
index 124d5e7f9a2..eb589346a0c 100644
--- a/test/integration/command-logging-and-monitoring/command_monitoring.test.ts
+++ b/test/integration/command-logging-and-monitoring/command_monitoring.test.ts
@@ -603,49 +603,4 @@ describe('Command Monitoring', function () {
         });
     }
   });
-
-  describe('Internal state references', function () {
-    let client;
-
-    beforeEach(function () {
-      client = this.configuration.newClient(
-        { writeConcern: { w: 1 } },
-        { maxPoolSize: 1, monitorCommands: true }
-      );
-    });
-
-    afterEach(function (done) {
-      client.close(done);
-    });
-
-    // NODE-1502
-    it('should not allow mutation of internal state from commands returned by event monitoring', function () {
-      const started = [];
-      const succeeded = [];
-      client.on('commandStarted', filterForCommands('insert', started));
-      client.on('commandSucceeded', filterForCommands('insert', succeeded));
-      const documentToInsert = { a: { b: 1 } };
-      const db = client.db(this.configuration.db);
-      return db
-        .collection('apm_test')
-        .insertOne(documentToInsert)
-        .then(r => {
-          expect(r).to.have.property('insertedId').that.is.an('object');
-          expect(started).to.have.lengthOf(1);
-          // Check if contents of returned document are equal to document inserted (by value)
-          expect(documentToInsert).to.deep.equal(started[0].command.documents[0]);
-          // Check if the returned document is a clone of the original. This confirms that the
-          // reference is not the same.
-          expect(documentToInsert !== started[0].command.documents[0]).to.equal(true);
-          expect(documentToInsert.a !== started[0].command.documents[0].a).to.equal(true);
-
-          started[0].command.documents[0].a.b = 2;
-          expect(documentToInsert.a.b).to.equal(1);
-
-          expect(started[0].commandName).to.equal('insert');
-          expect(started[0].command.insert).to.equal('apm_test');
-          expect(succeeded).to.have.lengthOf(1);
-        });
-    });
-  });
 });

From 31f941e4f7da4aec0cd614512ceb26c46c3f595e Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Tue, 21 Jan 2025 15:58:14 -0500
Subject: [PATCH 04/17] finish accounting for other BSON types

---
 src/mongo_logger.ts | 125 ++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 116 insertions(+), 9 deletions(-)

diff --git a/src/mongo_logger.ts b/src/mongo_logger.ts
index d49bbe6071a..d880484be4a 100644
--- a/src/mongo_logger.ts
+++ b/src/mongo_logger.ts
@@ -1,7 +1,24 @@
 import { inspect, promisify } from 'util';
 import { isUint8Array } from 'util/types';
 
-import { type Document, EJSON, type EJSONOptions, type ObjectId } from './bson';
+import {
+  type Binary,
+  type BSONRegExp,
+  type BSONSymbol,
+  type Code,
+  type DBRef,
+  type Decimal128,
+  type Document,
+  type Double,
+  EJSON,
+  type EJSONOptions,
+  type Int32,
+  type Long,
+  type MaxKey,
+  type MinKey,
+  type ObjectId,
+  type Timestamp
+} from './bson';
 import type { CommandStartedEvent } from './cmap/command_monitoring_events';
 import type {
   ConnectionCheckedInEvent,
@@ -414,6 +431,20 @@ export interface LogConvertible extends Record<string, any> {
   toLog(): Record<string, any>;
 }
 
+type BSONObject =
+  | BSONRegExp
+  | BSONSymbol
+  | Code
+  | DBRef
+  | Decimal128
+  | Double
+  | Int32
+  | Long
+  | MaxKey
+  | MinKey
+  | ObjectId
+  | Timestamp
+  | Binary;
 /** @internal */
 export function stringifyWithMaxLen(
   value: any,
@@ -427,22 +458,98 @@ export function stringifyWithMaxLen(
     if (currentLength >= maxDocumentLength) {
       return undefined;
     }
+    // Account for root document
+    if (key === '') {
+      // Account for starting brace
+      currentLength += 1;
+      return value;
+    }
 
+    // +4 accounts for 2 quotation marks, colon and comma after value
     currentLength += key.length + 4;
 
     if (typeof value === 'string') {
-      currentLength += value.length;
+      // +2 accounts for quotes
+      currentLength += value.length + 2;
     } else if (typeof value === 'number' || typeof value === 'bigint') {
-      currentLength += 20;
+      currentLength += String(value).length;
     } else if (typeof value === 'boolean') {
       currentLength += value ? 4 : 5;
+    } else if ('buffer' in value && isUint8Array(value.buffer)) {
+      // Handle binData
+      currentLength += (value.buffer.byteLength + value.buffer.byteLength * 0.5) | 0;
     } else if (value != null && typeof value === 'object' && '_bsontype' in value) {
-      if (isUint8Array(value.buffer)) {
-        currentLength += (value.buffer.byteLength + value.buffer.byteLength * 0.5) | 0;
-      } else if (value._bsontype === 'Binary') {
-        currentLength += (value.position + value.position * 0.3) | 0;
-      } else if (value._bsontype === 'Code') {
-        currentLength += value.code.length;
+      const v = value as BSONObject;
+      if (v._bsontype === 'Binary') {
+        // This is an estimate based on the fact that the base64 is approximately 1.3x the length of
+        // the actual binary sequence
+        // Also accounting for stringified fields before the binary sequence and the fields after
+        // the binary sequence
+        currentLength += (value.position + value.position * 0.3 + 22 + 17) | 0;
+      } else if (v._bsontype === 'Code') {
+        // '{"$code":"<code>"}' or '{"$code":"<code>","$scope":<scope>}'
+        // TODO: Account for scope?
+        if (v.scope == null) {
+          currentLength += v.code.length + 10 + 2;
+        } else {
+          // Ignoring actual scope object
+          currentLength += v.code.length + 10 + 11;
+        }
+      } else if (v._bsontype === 'Decimal128') {
+        // TODO: Is this worth doing here?
+        currentLength += value.toExtendedJSON().length;
+      } else if (v._bsontype === 'Double') {
+        // Doesn't account for representing integers as <value>.0
+        if ('value' in v && typeof v.value === 'number') currentLength += String(v.value).length;
+      } else if (v._bsontype === 'Int32') {
+        if ('value' in v && typeof v.value === 'number') currentLength += String(v.value).length;
+      } else if (v._bsontype === 'Long') {
+        if ('toString' in v && typeof v.toString === 'function') {
+          currentLength += v.toString().length;
+        }
+      } else if (v._bsontype === 'MaxKey' || v._bsontype === 'MinKey') {
+        // '{"$maxKey":1}' or '{"$minKey":1}'
+        currentLength += 13;
+      } else if (v._bsontype === 'ObjectId') {
+        // '{"$oid":"XXXXXXXXXXXXXXXXXXXXXXXX"}'
+        currentLength += 35;
+      } else if (
+        v._bsontype === 'BSONRegExp' &&
+        'pattern' in v &&
+        typeof v.pattern === 'string' &&
+        'options' in v &&
+        typeof v.options === 'string'
+      ) {
+        // '{"$regularExpression":{"pattern":"<pattern>","options":"<options>"}}'
+        currentLength += 34 + v.pattern.length + 13 + v.options.length + 3;
+      } else if (v._bsontype === 'BSONSymbol' && 'value' in v && v.value === 'string') {
+        // '{"$symbol": "<value>"}'
+        currentLength += 12 + v.value.length + 2;
+      } else if (
+        v._bsontype === 'Timestamp' &&
+        't' in v &&
+        typeof v.t === 'string' &&
+        'i' in v &&
+        typeof v.i === 'string'
+      ) {
+        currentLength += 19 + String(v.t).length + 5 + String(v.i).length + 2;
+      } else if (v._bsontype === 'DBRef') {
+        // '{"$ref":"<collection>","$id":<stringified oid>}' or '{"$ref":"<collection>","$id":<stringified oid>,"$db":"test"}'
+        currentLength += 9;
+        // account for collection
+        if ('collection' in v) {
+          currentLength += v.collection.length + 1;
+        }
+
+        // account for db if present
+        if ('db' in v && typeof v.db === 'string') {
+          currentLength += 8 + v.db.length + 2;
+        }
+
+        // account for oid if present
+        if ('oid' in v) {
+          currentLength += 35;
+        }
       }
     }
 

From befdc475e3e947cd9431f50d7534924a316eedb1 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Wed, 22 Jan 2025 16:07:33 -0500
Subject: [PATCH 05/17] update comments

---
 src/mongo_logger.ts | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/src/mongo_logger.ts b/src/mongo_logger.ts
index d880484be4a..a9349366832 100644
--- a/src/mongo_logger.ts
+++ b/src/mongo_logger.ts
@@ -481,14 +481,12 @@ export function stringifyWithMaxLen(
     } else if (value != null && typeof value === 'object' && '_bsontype' in value) {
       const v = value as BSONObject;
       if (v._bsontype === 'Binary') {
-        // This is an estimate based on the fact that the base64 is approximately 1.3x the length of
-        // the actual binary sequence
-        // Also accounting for stringified fields before the binary sequence and the fields after
-        // the binary sequence
-        currentLength += (value.position + value.position * 0.3 + 22 + 17) | 0;
+        // '{"$binary":{"base64":"<base64 string>","subType":"XX"}}'
+        // This is an estimate based on the fact that the base64 is approximately 1.33x the length of
+        // the actual binary sequence https://en.wikipedia.org/wiki/Base64
+        currentLength += (22 + value.position + value.position * 0.33 + 18) | 0;
       } else if (v._bsontype === 'Code') {
         // '{"$code":"<code>"}' or '{"$code":"<code>","$scope":<scope>}'
-        // TODO: Account for scope?
         if (v.scope == null) {
           currentLength += v.code.length + 10 + 2;
         } else {
@@ -496,7 +494,6 @@ export function stringifyWithMaxLen(
           currentLength += v.code.length + 10 + 11;
         }
       } else if (v._bsontype === 'Decimal128') {
-        // TODO: Is this worth doing here?
         currentLength += value.toExtendedJSON().length;
       } else if (v._bsontype === 'Double') {
         // Doesn't account for representing integers as <value>.0

From 2c255257873ff5942379e35a8e44e8f439433db3 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Wed, 22 Jan 2025 17:36:34 -0500
Subject: [PATCH 06/17] update condition to check binary

---
 src/mongo_logger.ts | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/mongo_logger.ts b/src/mongo_logger.ts
index a9349366832..36b28ec080c 100644
--- a/src/mongo_logger.ts
+++ b/src/mongo_logger.ts
@@ -475,7 +475,12 @@ export function stringifyWithMaxLen(
       currentLength += String(value).length;
     } else if (typeof value === 'boolean') {
       currentLength += value ? 4 : 5;
-    } else if ('buffer' in value && isUint8Array(value.buffer)) {
+    } else if (
+      value != null &&
+      typeof value === 'object' &&
+      'buffer' in value &&
+      isUint8Array(value.buffer)
+    ) {
       // Handle binData
       currentLength += (value.buffer.byteLength + value.buffer.byteLength * 0.5) | 0;
     } else if (value != null && typeof value === 'object' && '_bsontype' in value) {
@@ -490,7 +495,7 @@ export function stringifyWithMaxLen(
         if (v.scope == null) {
           currentLength += v.code.length + 10 + 2;
         } else {
-          // Ignoring actual scope object
+          // Ignoring actual scope object, so this undercounts
           currentLength += v.code.length + 10 + 11;
         }
       } else if (v._bsontype === 'Decimal128') {
@@ -531,6 +536,7 @@ export function stringifyWithMaxLen(
       ) {
         currentLength += 19 + String(v.t).length + 5 + String(v.i).length + 2;
       } else if (v._bsontype === 'DBRef') {
+        // TODO: Handle fields property; currently undercounts
         // '{"$ref":"<collection>","$id":<stringified oid>}' or '{"$ref":"<collection>","$id":<stringified oid>,"$db":"test"}'
         currentLength += 9;
         // account for collection
@@ -547,6 +553,8 @@ export function stringifyWithMaxLen(
         if ('oid' in v) {
           currentLength += 35;
         }
+      } else {
+        // Unknown BSON type, handle same as plain objects
       }
     }
 

From 0e08c227f8b9dcab1cd795ab7901dc806cc49958 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Wed, 22 Jan 2025 17:37:08 -0500
Subject: [PATCH 07/17] add wip tests

---
 test/unit/mongo_logger.test.ts | 196 ++++++++++++++++++++++++++++++++-
 1 file changed, 195 insertions(+), 1 deletion(-)

diff --git a/test/unit/mongo_logger.test.ts b/test/unit/mongo_logger.test.ts
index fff75bf9a21..f25fc90c22b 100644
--- a/test/unit/mongo_logger.test.ts
+++ b/test/unit/mongo_logger.test.ts
@@ -1,4 +1,16 @@
-import { EJSON, ObjectId } from 'bson';
+import {
+  BSONRegExp,
+  BSONSymbol,
+  Code,
+  DBRef,
+  Double,
+  EJSON,
+  Int32,
+  Long,
+  MaxKey,
+  MinKey,
+  ObjectId
+} from 'bson';
 import { expect } from 'chai';
 import * as sinon from 'sinon';
 import { Readable, Writable } from 'stream';
@@ -1612,3 +1624,185 @@ describe('class MongoLogger', function () {
     }
   });
 });
+
+describe('stringifyWithMaxLen', function () {
+  let returnVal: string;
+
+  describe('when stringifying a string field', function () {
+    it('does not prematurely redact the next key', function () {
+      const doc = {
+        a: 'aaa',
+        b: 'bbb'
+      };
+
+      returnVal = stringifyWithMaxLen(doc, 13);
+      expect(returnVal).to.contain('"b...');
+    });
+  });
+
+  describe('when stringifying a number field', function () {
+    it('does not prematurely redact the next key', function () {
+      const doc = {
+        a: 1000,
+        b: 'bbb'
+      };
+      returnVal = stringifyWithMaxLen(doc, 12);
+
+      expect(returnVal).to.contain('"b...');
+    });
+  });
+
+  describe('when stringifying a bigint field', function () {
+    it('does not prematurely redact the next key', function () {
+      const doc = {
+        a: 1000n,
+        b: 'bbb'
+      };
+      returnVal = stringifyWithMaxLen(doc, 12);
+
+      expect(returnVal).to.contain('"b...');
+    });
+  });
+
+  describe('when stringifying a BSON Code field', function () {
+    it('does not prematurely redact the next key', function () {
+      const doc = {
+        c: new Code('console.log();'),
+        b: 'bbb'
+      };
+      returnVal = stringifyWithMaxLen(doc, 34);
+
+      expect(returnVal).to.contain('"b...');
+    });
+  });
+
+  describe('when stringifying a BSON Decimal128 field', function () {});
+
+  describe('when stringifying a BSON Double field', function () {
+    it('does not prematurely redact the next key', function () {
+      const doc = {
+        c: new Double(123.1),
+        b: 'bbb'
+      };
+      returnVal = stringifyWithMaxLen(doc, 13);
+
+      expect(returnVal).to.contain('"b...');
+    });
+  });
+
+  describe('when stringifying a BSON Int32 field', function () {
+    it('does not prematurely redact the next key', function () {
+      const doc = {
+        c: new Int32(123),
+        b: 'bbb'
+      };
+      returnVal = stringifyWithMaxLen(doc, 11);
+
+      expect(returnVal).to.contain('"b...');
+    });
+  });
+
+  describe('when stringifying a BSON Long field', function () {
+    it('does not prematurely redact the next key', function () {
+      const doc = {
+        c: new Long(123),
+        b: 'bbb'
+      };
+      returnVal = stringifyWithMaxLen(doc, 11);
+
+      expect(returnVal).to.contain('"b...');
+    });
+  });
+
+  describe('when stringifying a BSON MaxKey field', function () {
+    it('does not prematurely redact the next key', function () {
+      const doc = {
+        c: new MaxKey(),
+        b: 'bbb'
+      };
+      returnVal = stringifyWithMaxLen(doc, 21);
+
+      expect(returnVal).to.contain('"b...');
+    });
+  });
+
+  describe('when stringifying a BSON MinKey field', function () {
+    it('does not prematurely redact the next key', function () {
+      const doc = {
+        c: new MinKey(),
+        b: 'bbb'
+      };
+      returnVal = stringifyWithMaxLen(doc, 21);
+
+      expect(returnVal).to.contain('"b...');
+    });
+  });
+
+  describe('when stringifying a BSON ObjectId field', function () {
+    it('does not prematurely redact the next key', function () {
+      const doc = {
+        c: new ObjectId(),
+        b: 'bbb'
+      };
+      returnVal = stringifyWithMaxLen(doc, 43);
+
+      expect(returnVal).to.contain('"b...');
+    });
+  });
+
+  describe('when stringifying a BSON BSONRegExp field', function () {
+    it('does not prematurely redact the next key', function () {
+      const doc = {
+        c: new BSONRegExp('testRegex', 'is'),
+        b: 'bbb'
+      };
+      returnVal = stringifyWithMaxLen(doc, 69);
+
+      expect(returnVal).to.contain('"b...');
+    });
+  });
+
+  describe('when stringifying a BSON BSONSymbol field', function () {
+    it('does not prematurely redact the next key', function () {
+      const doc = {
+        c: new BSONSymbol('testSymbol'),
+        b: 'bbb'
+      };
+      returnVal = stringifyWithMaxLen(doc, 32);
+
+      expect(returnVal).to.contain('"b...');
+    });
+  });
+
+  describe('when stringifying a BSON DBRef field', function () {
+    describe('when db, collection, oid and fields are defined', function () {
+      // TODO
+    });
+
+    describe('when db, collection and oid are defined', function () {
+      it('does not prematurely redact the next key', function () {
+        const oid = new ObjectId();
+        const doc = {
+          c: new DBRef('coll', oid, 'db'),
+          b: 'bbb'
+        };
+        returnVal = stringifyWithMaxLen(doc, 76);
+
+        expect(returnVal).to.contain('"b...');
+      });
+    });
+
+    describe('when collection and oid are defined', function () {
+      it('does not prematurely redact the next key', function () {
+        const oid = new ObjectId();
+        const doc = {
+          c: new DBRef('coll', oid),
+          b: 'bbb'
+        };
+        returnVal = stringifyWithMaxLen(doc, 65);
+
+        expect(returnVal).to.contain('"b...');
+      });
+    });
+  });
+});

From 891cee34fbbbf35298bd8f71955389fb1dd55037 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Wed, 22 Jan 2025 18:26:55 -0500
Subject: [PATCH 08/17] refactor to use switch

---
 src/mongo_logger.ts | 151 ++++++++++++++++++--------------------------
 1 file changed, 63 insertions(+), 88 deletions(-)

diff --git a/src/mongo_logger.ts b/src/mongo_logger.ts
index 36b28ec080c..6b10ce4cb2f 100644
--- a/src/mongo_logger.ts
+++ b/src/mongo_logger.ts
@@ -468,96 +468,71 @@ export function stringifyWithMaxLen(
     // +4 accounts for 2 quotation marks, colon and comma after value
     currentLength += key.length + 4;
 
-    if (typeof value === 'string') {
-      // +2 accounts for quotes
-      currentLength += value.length + 2;
-    } else if (typeof value === 'number' || typeof value === 'bigint') {
-      currentLength += String(value).length;
-    } else if (typeof value === 'boolean') {
-      currentLength += value ? 4 : 5;
-    } else if (
-      value != null &&
-      typeof value === 'object' &&
-      'buffer' in value &&
-      isUint8Array(value.buffer)
-    ) {
-      // Handle binData
-      currentLength += (value.buffer.byteLength + value.buffer.byteLength * 0.5) | 0;
-    } else if (value != null && typeof value === 'object' && '_bsontype' in value) {
-      const v = value as BSONObject;
-      if (v._bsontype === 'Binary') {
-        // '{"$binary":{"base64":"<base64 string>","subType":"XX"}}'
-        // This is an estimate based on the fact that the base64 is approximately 1.33x the length of
-        // the actual binary sequence https://en.wikipedia.org/wiki/Base64
-        currentLength += (22 + value.position + value.position * 0.33 + 18) | 0;
-      } else if (v._bsontype === 'Code') {
-        // '{"$code":"<code>"}' or '{"$code":"<code>","$scope":<scope>}'
-        if (v.scope == null) {
-          currentLength += v.code.length + 10 + 2;
-        } else {
-          // Ignoring actual scope object, so this undercounts
-          currentLength += v.code.length + 10 + 11;
-        }
-      } else if (v._bsontype === 'Decimal128') {
-        currentLength += value.toExtendedJSON().length;
-      } else if (v._bsontype === 'Double') {
-        // Doesn't account for representing integers as <value>.0
-        if ('value' in v && typeof v.value === 'number') currentLength += String(v.value).length;
-      } else if (v._bsontype === 'Int32') {
-        if ('value' in v && typeof v.value === 'number') currentLength += String(v.value).length;
-      } else if (v._bsontype === 'Long') {
-        if ('toString' in v && typeof v.toString === 'function') {
-          currentLength += v.toString().length;
-        }
-      } else if (v._bsontype === 'MaxKey' || v._bsontype === 'MinKey') {
-        // '{"$maxKey":1}' or '{"$minKey":1}'
-        currentLength += 13;
-      } else if (v._bsontype === 'ObjectId') {
-        // '{"$oid":"XXXXXXXXXXXXXXXXXXXXXXXX"}'
-        currentLength += 35;
-      } else if (
-        v._bsontype === 'BSONRegExp' &&
-        'pattern' in v &&
-        typeof v.pattern === 'string' &&
-        'options' in v &&
-        typeof v.options === 'string'
-      ) {
-        // '{"$regularExpression":{"pattern":"<pattern>","options":"<options>"}}'
-        currentLength += 34 + v.pattern.length + 13 + v.options.length + 3;
-      } else if (v._bsontype === 'BSONSymbol' && 'value' in v && v.value === 'string') {
-        // '{"$symbol": "<value>"}'
-        currentLength += 12 + v.value.length + 2;
-      } else if (
-        v._bsontype === 'Timestamp' &&
-        't' in v &&
-        typeof v.t === 'string' &&
-        'i' in v &&
-        typeof v.i === 'string'
-      ) {
-        currentLength += 19 + String(v.t).length + 5 + String(v.i).length + 2;
-      } else if (v._bsontype === 'DBRef') {
-        // TODO: Handle fields property; currently undercounts
-        // '{"$ref":"<collection>","$id":<stringified oid>}' or '{"$ref":"<collection>","$id":<stringified oid>,"$db":"test"}'
-        currentLength += 9;
-        // account for collection
-        if ('collection' in v) {
-          currentLength += v.collection.length + 1;
-        }
-
-        // account for db if present
-        if ('db' in v && typeof v.db === 'string') {
-          currentLength += 8 + v.db.length + 2;
-        }
-
-        // account for oid if present
-        if ('oid' in v) {
-          currentLength += 35;
+    if (value == null) return value;
+
+    switch (typeof value) {
+      case 'string':
+        // +2 accounts for quotes
+        currentLength += value.length + 2;
+        break;
+      case 'number':
+      case 'bigint':
+        currentLength += String(value).length;
+        break;
+      case 'boolean':
+        currentLength += value ? 4 : 5;
+        break;
+      case 'object':
+        if ('buffer' in value && isUint8Array(value.buffer)) {
+          // Handle binData
+          currentLength += (value.buffer.byteLength + value.buffer.byteLength * 0.5) | 0;
+        } else if ('_bsontype' in value) {
+          const v = value as BSONObject;
+          switch (v._bsontype) {
+            case 'Int32':
+              currentLength += String(v.value).length;
+              break;
+            case 'Double':
+              // Doesn't account for representing integers as <value>.0
+              currentLength += String(v.value).length;
+              break;
+            case 'Long':
+              currentLength += v.toString().length;
+              break;
+            case 'ObjectId':
+              // '{"$oid":"XXXXXXXXXXXXXXXXXXXXXXXX"}'
+              currentLength += 35;
+              break;
+            case 'MaxKey':
+            case 'MinKey':
+              // '{"$maxKey":1}' or '{"$minKey":1}'
+              currentLength += 13;
+              break;
+            case 'Binary':
+              // '{"$binary":{"base64":"<base64 string>","subType":"XX"}}'
+              // This is an estimate based on the fact that the base64 is approximately 1.33x the length of
+              // the actual binary sequence https://en.wikipedia.org/wiki/Base64
+              currentLength += (22 + value.position + value.position * 0.33 + 18) | 0;
+              break;
+            case 'Timestamp':
+              currentLength += 19 + String(v.t).length + 5 + String(v.i).length + 2;
+              break;
+            case 'Code':
+              // '{"$code":"<code>"}' or '{"$code":"<code>","$scope":<scope>}'
+              if (v.scope == null) {
+                currentLength += v.code.length + 10 + 2;
+              } else {
+                // Ignoring actual scope object, so this undercounts by a significant amount
+                currentLength += v.code.length + 10 + 11;
+              }
+              break;
+            case 'BSONRegExp':
+              // '{"$regularExpression":{"pattern":"<pattern>","options":"<options>"}}'
+              currentLength += 34 + v.pattern.length + 13 + v.options.length + 3;
+              break;
+          }
         }
-      } else {
-        // Unknown BSON type, handle same as plain objects
-      }
     }
-
     return value;
   };
 

From b2fddf18639429908307203fa3b41b24dd0c9802 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Thu, 23 Jan 2025 11:41:15 -0500
Subject: [PATCH 09/17] remove unneeded tests

---
 test/unit/mongo_logger.test.ts | 58 ----------------------------------
 1 file changed, 58 deletions(-)

diff --git a/test/unit/mongo_logger.test.ts b/test/unit/mongo_logger.test.ts
index f25fc90c22b..b537ab73094 100644
--- a/test/unit/mongo_logger.test.ts
+++ b/test/unit/mongo_logger.test.ts
@@ -1676,8 +1676,6 @@ describe('stringifyWithMaxLen', function () {
     });
   });
 
-  describe('when stringifying a BSON Decimal128 field', function () {});
-
   describe('when stringifying a BSON Double field', function () {
     it('does not prematurely redact the next key', function () {
       const doc = {
@@ -1702,18 +1700,6 @@ describe('stringifyWithMaxLen', function () {
     });
   });
 
-  describe('when stringifying a BSON Long field', function () {
-    it('does not prematurely redact the next key', function () {
-      const doc = {
-        c: new Long(123),
-        b: 'bbb'
-      };
-      returnVal = stringifyWithMaxLen(doc, 11);
-
-      expect(returnVal).to.contain('"b...');
-    });
-  });
-
   describe('when stringifying a BSON MaxKey field', function () {
     it('does not prematurely redact the next key', function () {
       const doc = {
@@ -1761,48 +1747,4 @@ describe('stringifyWithMaxLen', function () {
       expect(returnVal).to.contain('"b...');
     });
   });
-
-  describe('when stringifying a BSON BSONSymbol field', function () {
-    it('does not prematurely redact the next key', function () {
-      const doc = {
-        c: new BSONSymbol('testSymbol'),
-        b: 'bbb'
-      };
-      returnVal = stringifyWithMaxLen(doc, 32);
-
-      expect(returnVal).to.contain('"b...');
-    });
-  });
-
-  describe('when stringifying a BSON DBRef field', function () {
-    describe('when db, collection, oid and fields are defined', function () {
-      // TODO
-    });
-
-    describe('when db, collection and oid are defined', function () {
-      it('does not prematurely redact the next key', function () {
-        const oid = new ObjectId();
-        const doc = {
-          c: new DBRef('coll', oid, 'db'),
-          b: 'bbb'
-        };
-        returnVal = stringifyWithMaxLen(doc, 76);
-
-        expect(returnVal).to.contain('"b...');
-      });
-    });
-
-    describe('when collection and oid are defined', function () {
-      it('does not prematurely redact the next key', function () {
-        const oid = new ObjectId();
-        const doc = {
-          c: new DBRef('coll', oid),
-          b: 'bbb'
-        };
-        returnVal = stringifyWithMaxLen(doc, 65);
-
-        expect(returnVal).to.contain('"b...');
-      });
-    });
-  });
 });

From 2876bdb5fc3b0bad93a9cbf39fb36b9fe83d9146 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Thu, 23 Jan 2025 17:54:02 -0500
Subject: [PATCH 10/17] Update test/unit/mongo_logger.test.ts

Co-authored-by: Neal Beeken <neal.beeken@mongodb.com>
---
 test/unit/mongo_logger.test.ts | 1 -
 1 file changed, 1 deletion(-)

diff --git a/test/unit/mongo_logger.test.ts b/test/unit/mongo_logger.test.ts
index b537ab73094..846309c0703 100644
--- a/test/unit/mongo_logger.test.ts
+++ b/test/unit/mongo_logger.test.ts
@@ -1,6 +1,5 @@
 import {
   BSONRegExp,
-  BSONSymbol,
   Code,
   DBRef,
   Double,

From 4b9cae0692eeb263af5e6569ae61416e46e9672a Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Thu, 23 Jan 2025 17:54:13 -0500
Subject: [PATCH 11/17] Update test/unit/mongo_logger.test.ts

Co-authored-by: Neal Beeken <neal.beeken@mongodb.com>
---
 test/unit/mongo_logger.test.ts | 1 -
 1 file changed, 1 deletion(-)

diff --git a/test/unit/mongo_logger.test.ts b/test/unit/mongo_logger.test.ts
index 846309c0703..b11c3100265 100644
--- a/test/unit/mongo_logger.test.ts
+++ b/test/unit/mongo_logger.test.ts
@@ -1,7 +1,6 @@
 import {
   BSONRegExp,
   Code,
-  DBRef,
   Double,
   EJSON,
   Int32,

From 52f2a4a94442f3eff2ef19a18b8011b43f0286da Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Thu, 23 Jan 2025 17:54:25 -0500
Subject: [PATCH 12/17] Update test/unit/mongo_logger.test.ts

Co-authored-by: Neal Beeken <neal.beeken@mongodb.com>
---
 test/unit/mongo_logger.test.ts | 1 -
 1 file changed, 1 deletion(-)

diff --git a/test/unit/mongo_logger.test.ts b/test/unit/mongo_logger.test.ts
index b11c3100265..fd54c3fc4a5 100644
--- a/test/unit/mongo_logger.test.ts
+++ b/test/unit/mongo_logger.test.ts
@@ -4,7 +4,6 @@ import {
   Double,
   EJSON,
   Int32,
-  Long,
   MaxKey,
   MinKey,
   ObjectId

From d99e3b7b1fc92c58d3ffb81db3591df8bfda867e Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Thu, 23 Jan 2025 18:14:47 -0500
Subject: [PATCH 13/17] address review comments

---
 src/mongo_logger.ts            |  6 ++++--
 test/unit/mongo_logger.test.ts | 22 ++++++++++------------
 2 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/src/mongo_logger.ts b/src/mongo_logger.ts
index 6b10ce4cb2f..db38d1a2ad5 100644
--- a/src/mongo_logger.ts
+++ b/src/mongo_logger.ts
@@ -493,8 +493,9 @@ export function stringifyWithMaxLen(
               currentLength += String(v.value).length;
               break;
             case 'Double':
-              // Doesn't account for representing integers as <value>.0
-              currentLength += String(v.value).length;
+              // Account for representing integers as <value>.0
+              currentLength +=
+                (v.value | 0) === v.value ? String(v.value).length + 2 : String(v.value).length;
               break;
             case 'Long':
               currentLength += v.toString().length;
@@ -515,6 +516,7 @@ export function stringifyWithMaxLen(
               currentLength += (22 + value.position + value.position * 0.33 + 18) | 0;
               break;
             case 'Timestamp':
+              // '{"$timestamp":{"t":<t>,"i":<i>}}'
               currentLength += 19 + String(v.t).length + 5 + String(v.i).length + 2;
               break;
             case 'Code':
diff --git a/test/unit/mongo_logger.test.ts b/test/unit/mongo_logger.test.ts
index fd54c3fc4a5..27b783f3492 100644
--- a/test/unit/mongo_logger.test.ts
+++ b/test/unit/mongo_logger.test.ts
@@ -1623,8 +1623,6 @@ describe('class MongoLogger', function () {
 });
 
 describe('stringifyWithMaxLen', function () {
-  let returnVal: string;
-
   describe('when stringifying a string field', function () {
     it('does not prematurely redact the next key', function () {
       const doc = {
@@ -1632,7 +1630,7 @@ describe('stringifyWithMaxLen', function () {
         b: 'bbb'
       };
 
-      returnVal = stringifyWithMaxLen(doc, 13);
+      const returnVal = stringifyWithMaxLen(doc, 13);
       expect(returnVal).to.contain('"b...');
     });
   });
@@ -1643,7 +1641,7 @@ describe('stringifyWithMaxLen', function () {
         a: 1000,
         b: 'bbb'
       };
-      returnVal = stringifyWithMaxLen(doc, 12);
+      const returnVal = stringifyWithMaxLen(doc, 12);
 
       expect(returnVal).to.contain('"b...');
     });
@@ -1655,7 +1653,7 @@ describe('stringifyWithMaxLen', function () {
         a: 1000n,
         b: 'bbb'
       };
-      returnVal = stringifyWithMaxLen(doc, 12);
+      const returnVal = stringifyWithMaxLen(doc, 12);
 
       expect(returnVal).to.contain('"b...');
     });
@@ -1667,7 +1665,7 @@ describe('stringifyWithMaxLen', function () {
         c: new Code('console.log();'),
         b: 'bbb'
       };
-      returnVal = stringifyWithMaxLen(doc, 34);
+      const returnVal = stringifyWithMaxLen(doc, 34);
 
       expect(returnVal).to.contain('"b...');
     });
@@ -1679,7 +1677,7 @@ describe('stringifyWithMaxLen', function () {
         c: new Double(123.1),
         b: 'bbb'
       };
-      returnVal = stringifyWithMaxLen(doc, 13);
+      const returnVal = stringifyWithMaxLen(doc, 13);
 
       expect(returnVal).to.contain('"b...');
     });
@@ -1691,7 +1689,7 @@ describe('stringifyWithMaxLen', function () {
         c: new Int32(123),
         b: 'bbb'
       };
-      returnVal = stringifyWithMaxLen(doc, 11);
+      const returnVal = stringifyWithMaxLen(doc, 11);
 
       expect(returnVal).to.contain('"b...');
     });
@@ -1703,7 +1701,7 @@ describe('stringifyWithMaxLen', function () {
         c: new MaxKey(),
         b: 'bbb'
       };
-      returnVal = stringifyWithMaxLen(doc, 21);
+      const returnVal = stringifyWithMaxLen(doc, 21);
 
       expect(returnVal).to.contain('"b...');
     });
@@ -1715,7 +1713,7 @@ describe('stringifyWithMaxLen', function () {
         c: new MinKey(),
         b: 'bbb'
       };
-      returnVal = stringifyWithMaxLen(doc, 21);
+      const returnVal = stringifyWithMaxLen(doc, 21);
 
       expect(returnVal).to.contain('"b...');
     });
@@ -1727,7 +1725,7 @@ describe('stringifyWithMaxLen', function () {
         c: new ObjectId(),
         b: 'bbb'
       };
-      returnVal = stringifyWithMaxLen(doc, 43);
+      const returnVal = stringifyWithMaxLen(doc, 43);
 
       expect(returnVal).to.contain('"b...');
     });
@@ -1739,7 +1737,7 @@ describe('stringifyWithMaxLen', function () {
         c: new BSONRegExp('testRegex', 'is'),
         b: 'bbb'
       };
-      returnVal = stringifyWithMaxLen(doc, 69);
+      const returnVal = stringifyWithMaxLen(doc, 69);
 
       expect(returnVal).to.contain('"b...');
     });

From 35fc08879d275134f440f25bcdfa989811421db6 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Fri, 24 Jan 2025 13:51:06 -0500
Subject: [PATCH 14/17] address review

---
 src/mongo_logger.ts | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/mongo_logger.ts b/src/mongo_logger.ts
index db38d1a2ad5..588542da697 100644
--- a/src/mongo_logger.ts
+++ b/src/mongo_logger.ts
@@ -466,6 +466,8 @@ export function stringifyWithMaxLen(
     }
 
     // +4 accounts for 2 quotation marks, colon and comma after value
+    // Note that this potentially undercounts since it does not account for escape sequences which
+    // will have an additional backslash added to them once passed through JSON.stringify.
     currentLength += key.length + 4;
 
     if (value == null) return value;
@@ -473,6 +475,7 @@ export function stringifyWithMaxLen(
     switch (typeof value) {
       case 'string':
         // +2 accounts for quotes
+        // Note that this potentially undercounts similarly to the key length calculation
         currentLength += value.length + 2;
         break;
       case 'number':
@@ -483,9 +486,9 @@ export function stringifyWithMaxLen(
         currentLength += value ? 4 : 5;
         break;
       case 'object':
-        if ('buffer' in value && isUint8Array(value.buffer)) {
+        if (isUint8Array(value)) {
           // Handle binData
-          currentLength += (value.buffer.byteLength + value.buffer.byteLength * 0.5) | 0;
+          currentLength += (value.byteLength + value.byteLength * 0.5) | 0;
         } else if ('_bsontype' in value) {
           const v = value as BSONObject;
           switch (v._bsontype) {

From 52c6f16e897d16f024d7c675a30ccbbc961562b9 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Fri, 24 Jan 2025 13:52:04 -0500
Subject: [PATCH 15/17] test lint

---
 test/unit/mongo_logger.test.ts | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/test/unit/mongo_logger.test.ts b/test/unit/mongo_logger.test.ts
index 27b783f3492..da47bd8399c 100644
--- a/test/unit/mongo_logger.test.ts
+++ b/test/unit/mongo_logger.test.ts
@@ -1,13 +1,4 @@
-import {
-  BSONRegExp,
-  Code,
-  Double,
-  EJSON,
-  Int32,
-  MaxKey,
-  MinKey,
-  ObjectId
-} from 'bson';
+import { BSONRegExp, Code, Double, EJSON, Int32, MaxKey, MinKey, ObjectId } from 'bson';
 import { expect } from 'chai';
 import * as sinon from 'sinon';
 import { Readable, Writable } from 'stream';

From 1019f5ecdcd1ac5813da4b609ae401c3dada4ca7 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Fri, 24 Jan 2025 13:52:34 -0500
Subject: [PATCH 16/17] remove hybrid uint8array/binary case

---
 src/mongo_logger.ts | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/mongo_logger.ts b/src/mongo_logger.ts
index 588542da697..2cac06f1b26 100644
--- a/src/mongo_logger.ts
+++ b/src/mongo_logger.ts
@@ -486,10 +486,7 @@ export function stringifyWithMaxLen(
         currentLength += value ? 4 : 5;
         break;
       case 'object':
-        if (isUint8Array(value)) {
-          // Handle binData
-          currentLength += (value.byteLength + value.byteLength * 0.5) | 0;
-        } else if ('_bsontype' in value) {
+        if ('_bsontype' in value) {
           const v = value as BSONObject;
           switch (v._bsontype) {
             case 'Int32':

From 7e70174d0ca7eb9294e3c874e92b63cf20cb0b66 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Fri, 24 Jan 2025 14:18:47 -0500
Subject: [PATCH 17/17] handle Uint8Array case

---
 src/mongo_logger.ts | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/mongo_logger.ts b/src/mongo_logger.ts
index 2cac06f1b26..c6e581c59e8 100644
--- a/src/mongo_logger.ts
+++ b/src/mongo_logger.ts
@@ -486,7 +486,12 @@ export function stringifyWithMaxLen(
         currentLength += value ? 4 : 5;
         break;
       case 'object':
-        if ('_bsontype' in value) {
+        if (isUint8Array(value)) {
+          // '{"$binary":{"base64":"<base64 string>","subType":"XX"}}'
+          // This is an estimate based on the fact that the base64 is approximately 1.33x the length of
+          // the actual binary sequence https://en.wikipedia.org/wiki/Base64
+          currentLength += (22 + value.byteLength + value.byteLength * 0.33 + 18) | 0;
+        } else if ('_bsontype' in value) {
           const v = value as BSONObject;
           switch (v._bsontype) {
             case 'Int32':