DeprecationWarning: Listening to events on the Db class has been deprecated and will be removed in the next major version

[Systerr]

Do you want to request a feature or report a bug?
bug (deprecation warning)

What is the current behavior?
On start we have deprecation warning into console

If the current behavior is a bug, please provide the steps to reproduce.

(node:9455) DeprecationWarning: Listening to events on the Db class has been deprecated and will be removed in the next major version.
    at _setClient (node_modules/mongoose/lib/connection.js:943:6)
    at node_modules/mongoose/lib/connection.js:839:7
    at node_modules/mongodb/lib/utils.js:693:5
    at node_modules/mongodb/lib/mongo_client.js:227:7
    at connectCallback (node_modules/mongodb/lib/operations/connect.js:366:5)
    at node_modules/mongodb/lib/operations/connect.js:602:5
    at Object.connectHandler [as callback] (/node_modules/mongodb/lib/core/sdam/topology.js:297:43)
    at processWaitQueue (node_modules/mongodb/lib/core/sdam/topology.js:1048:21)
    at NativeTopology.serverUpdateHandler (node_modules/mongodb/lib/core/sdam/topology.js:567:7)
    at Server.emit (events.js:315:20)

What is the expected behavior?
No deprecation warning
What are the versions of Node.js, Mongoose and MongoDB you are using? Note that "latest" is not a version.
Latest 5.11.16

I digged in into warning and found why this happens:

1. This introduced into mongo driver on version v3.6.4 refactor: deprecate Db.on and Db.once mongodb/node-mongodb-native#2610 as part on preparation of driver v4 release
2. Latest mongoose 5.11.16 introduced mongo drive update Upgrade mongodb driver to 3.6.4 #9893
3. Original change happens because of refactor(db)!: suppress Db events mongodb/node-mongodb-native#2251

[Systerr]

https://github.com/Automattic/mongoose/blob/5.11.16/lib/connection.js#L943

[pnutmath]

https://jira.mongodb.org/browse/NODE-1709?focusedCommentId=2962047&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-2962047

Only MongoClient will receive events not DB class in future

[purpshell]

how does this get fixed?

[lantw44]

The warning still exists in mongoose 5.11.18:

(node:90089) DeprecationWarning: Listening to events on the Db class has been deprecated and will be removed in the next major version.
    at _setClient (node_modules/mongoose/lib/connection.js:932:10)
    at node_modules/mongoose/lib/connection.js:838:7
    at node_modules/mongodb/lib/utils.js:693:5
    at node_modules/mongodb/lib/mongo_client.js:227:7
    at connectCallback (node_modules/mongodb/lib/operations/connect.js:366:5)
    at node_modules/mongodb/lib/operations/connect.js:602:5
    at connectHandler (node_modules/mongodb/lib/core/sdam/topology.js:297:43)
    at cb (node_modules/mongodb/lib/core/sdam/topology.js:681:26)
    at node_modules/mongodb/lib/cmap/connection_pool.js:350:13
    at handleOperationResult (node_modules/mongodb/lib/core/sdam/server.js:558:5)
    at MessageStream.messageHandler (node_modules/mongodb/lib/cmap/connection.js:277:5)
    at MessageStream.emit (events.js:315:20)
    at MessageStream.EventEmitter.emit (domain.js:529:15)
    at processIncomingData (node_modules/mongodb/lib/cmap/message_stream.js:144:12)
    at MessageStream._write (node_modules/mongodb/lib/cmap/message_stream.js:42:5)
    at writeOrBuffer (internal/streams/writable.js:358:12)

[troykelly]

@vkarpov15 can this please be reopened until it's confirmed resolved?

[vkarpov15]

@lantw44 @troykelly do you have useUnifiedTopology: true set?

[lantw44]

@lantw44 @troykelly do you have useUnifiedTopology: true set?

Yes, useUnifiedTopology: true is set when calling mongoose.createConnection.