fix(NODE-1502): command monitoring objects hold internal state refere…

…nces (#2832)

src/cmap/command_monitoring_events.ts

@@ -181,7 +181,7 @@ const OP_QUERY_KEYS = [
 function extractCommand(command: WriteProtocolMessageType): Document {
   if (command instanceof GetMore) {
     return {
-      getMore: command.cursorId,
+      getMore: deepCopy(command.cursorId),
       collection: collectionName(command),
       batchSize: command.numberToReturn
     };
@@ -190,15 +190,15 @@ function extractCommand(command: WriteProtocolMessageType): Document {
   if (command instanceof KillCursor) {
     return {
       killCursors: collectionName(command),
-      cursors: command.cursorIds
+      cursors: deepCopy(command.cursorIds)
     };
   }
 
   if (command instanceof Msg) {
-    return command.command;
+    return deepCopy(command.command);
   }
 
-  if (command.query && command.query.$query) {
+  if (command.query?.$query) {
     let result: Document;
     if (command.ns === 'admin.$cmd') {
       // up-convert legacy command
@@ -208,15 +208,15 @@ function extractCommand(command: WriteProtocolMessageType): Document {
       result = { find: collectionName(command) };
       Object.keys(LEGACY_FIND_QUERY_MAP).forEach(key => {
         if (typeof command.query[key] !== 'undefined') {
-          result[LEGACY_FIND_QUERY_MAP[key]] = command.query[key];
+          result[LEGACY_FIND_QUERY_MAP[key]] = deepCopy(command.query[key]);
         }
       });
     }
 
     Object.keys(LEGACY_FIND_OPTIONS_MAP).forEach(key => {
       const legacyKey = key as keyof typeof LEGACY_FIND_OPTIONS_MAP;
       if (typeof command[legacyKey] !== 'undefined') {
-        result[LEGACY_FIND_OPTIONS_MAP[legacyKey]] = command[legacyKey];
+        result[LEGACY_FIND_OPTIONS_MAP[legacyKey]] = deepCopy(command[legacyKey]);
       }
     });
 
@@ -234,11 +234,23 @@ function extractCommand(command: WriteProtocolMessageType): Document {
     if (command.query.$explain) {
       return { explain: result };
     }
-
     return result;
   }
 
-  return command.query ? command.query : command;
+  const clonedQuery: Record<string, unknown> = {};
+  const clonedCommand: Record<string, unknown> = {};
+  if (command.query) {
+    for (const k in command.query) {
+      clonedQuery[k] = deepCopy(command.query[k]);
+    }
+    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) {

test/functional/apm.test.js

@@ -658,6 +658,43 @@ describe('APM', function () {
     }
   });
 
+  // NODE-1502
+  it('should not allow mutation of internal state from commands returned by event monitoring', function () {
+    const started = [];
+    const succeeded = [];
+    const client = this.configuration.newClient(
+      { writeConcern: { w: 1 } },
+      { maxPoolSize: 1, monitorCommands: true }
+    );
+    client.on('commandStarted', filterForCommands('insert', started));
+    client.on('commandSucceeded', filterForCommands('insert', succeeded));
+    let documentToInsert = { a: { b: 1 } };
+    return client
+      .connect()
+      .then(client => {
+        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);
+        return client.close();
+      });
+  });
+
   describe('spec tests', function () {
     before(function () {
       return setupDatabase(this.configuration);

test/functional/multiple_db.test.js

@@ -85,7 +85,9 @@ describe('Multiple Databases', function () {
             { returnDocument: ReturnDocument.AFTER },
             function (err) {
               expect(err).to.not.exist;
-              client.close(done);
+              collection.drop(() => {
+                client.close(done);
+              });
             }
           );
         });

test/unit/cmap/command_monitoring_events.test.js

@@ -0,0 +1,64 @@
+'use strict';
+
+const { Msg, Query, GetMore, KillCursor } = require('../../../src/cmap/commands');
+const { CommandStartedEvent } = require('../../../src/cmap/command_monitoring_events');
+const { expect } = require('chai');
+const { Long } = require('bson');
+
+describe('Command Monitoring Events - unit/cmap', function () {
+  const commands = [
+    new Query('admin.$cmd', { a: { b: 10 }, $query: { b: 10 } }, {}),
+    new Query('hello', { a: { b: 10 }, $query: { b: 10 } }, {}),
+    new Msg('admin.$cmd', { b: { c: 20 } }, {}),
+    new Msg('hello', { b: { c: 20 } }, {}),
+    new GetMore('admin.$cmd', Long.fromNumber(10)),
+    new GetMore('hello', Long.fromNumber(10)),
+    new KillCursor('admin.$cmd', [Long.fromNumber(100), Long.fromNumber(200)]),
+    new KillCursor('hello', [Long.fromNumber(100), Long.fromNumber(200)]),
+    { ns: 'admin.$cmd', query: { $query: { a: 16 } } },
+    { ns: 'hello there', f1: { h: { a: 52, b: { c: 10, d: [1, 2, 3, 5] } } } }
+  ];
+
+  for (const command of commands) {
+    it(`should make a deep copy of object of type: ${command.constructor.name}`, () => {
+      const ev = new CommandStartedEvent({ id: 'someId', address: 'someHost' }, command);
+      if (command instanceof Query) {
+        if (command.ns === 'admin.$cmd') {
+          expect(ev.command !== command.query.$query).to.equal(true);
+          for (const k in command.query.$query) {
+            expect(ev.command[k]).to.deep.equal(command.query.$query[k]);
+          }
+        } else {
+          expect(ev.command.filter !== command.query.$query).to.equal(true);
+          for (const k in command.query.$query) {
+            expect(ev.command.filter[k]).to.deep.equal(command.query.$query[k]);
+          }
+        }
+      } else if (command instanceof Msg) {
+        expect(ev.command !== command.command).to.equal(true);
+        expect(ev.command).to.deep.equal(command.command);
+      } else if (command instanceof GetMore) {
+        // NOTE: BSON Longs pass strict equality when their internal values are equal
+        // i.e.
+        // let l1 = Long(10);
+        // let l2 = Long(10);
+        // l1 === l2 // returns true
+        // expect(ev.command.getMore !== command.cursorId).to.equal(true);
+        expect(ev.command.getMore).to.deep.equal(command.cursorId);
+
+        ev.command.getMore = Long.fromNumber(50128);
+        expect(command.cursorId).to.not.deep.equal(ev.command.getMore);
+      } else if (command instanceof KillCursor) {
+        expect(ev.command.cursors !== command.cursorIds).to.equal(true);
+        expect(ev.command.cursors).to.deep.equal(command.cursorIds);
+      } else if (typeof command === 'object') {
+        if (command.ns === 'admin.$cmd') {
+          expect(ev.command !== command.query.$query).to.equal(true);
+          for (const k in command.query.$query) {
+            expect(ev.command[k]).to.deep.equal(command.query.$query[k]);
+          }
+        }
+      }
+    });
+  }
+});