onTeamsMembersAddedEvent handler doesn't run

Versions

What package version of the SDK are you using: ^4.9.0

What nodejs version are you using: v13.6.0

What browser version are you using: Chrome 81.0.4044.138

What os are you using: MacOS 10.14.6

Describe the bug

TeamsActivityHandler.onTeamsMembersAddedEvent handler doesn’t fire.

To Reproduce

1. Inside Teams, Upload custom app -> select .zip -> Add
2. Observe that app home screen is now open in web app
3. Observe POST request to bot endpoint (using ngrok)

// POST /api/messages

{
    "membersAdded": [
        {
            "id": "29:1hjD7KSnkCFRm5xasdfd4Jt0Kw9Ehhk56B_T0KB6b1428DEgDa0s7bOAV71kcBtXa_w",
            "aadObjectId": "32adf3ba-8b97-44c7-a06c-e2d4f7sdsda38cbc"
        },
        {
            "id": "28:85a028da-48d7-4237-b1ac-4231c4544fe8"
        }
    ],
    "type": "conversationUpdate",
    "timestamp": "2020-05-13T09:38:52.6203787Z",
    "id": "f:e9e5ac1a-dbf0-38b0-1d1f-dd6b5c5b34fe",
    "channelId": "msteams",
    "serviceUrl": "https://smba.trafficmanager.net/amer/",
    "from": {
        "id": "29:1hjD7KSnkCmRm5x3iCCDMB6Ivlq4AYc1aID9JnJB4Jt0Kw9Ehhk56B_T0KB6b1428DEgDa0s7bOAV71kcBtXa_w",
        "aadObjectId": "12alf9ba-8b97-44c7-a06c-e2d4f7a38cbc"
    },
    "conversation": {
        "conversationType": "personal",
        "tenantId": "a2aee900-2e61-4451-97f0-f45baa3db628",
        "id": "a:14mtI5vt1TkHonyxiEu3mNptiDttg80gtLHGBUWkdzmvmOrDlYSsx7ELKGMegDBxuvpPFQd0bKL2CUrRVfHrAdOXGlfn64mej1UOCAQlal-j4N-OOo9YUnXe9q5L-yDsc"
    },
    "recipient": {
        "id": "28:85b828da-48f7-4237-b0ac-4231c4545fe8",
        "name": "MyBot"
    },
    "channelData": {
        "tenant": {
            "id": "a2aee900-2e61-4451-97f0-f45baa3db628"
        }
    }
}

// server.js
const bot = new MyBot()
app.post('/api/messages', async (req, res) => {
  adapter.processActivity(req, res, async (context) => {
    if (context.activity.type !== ActivityTypes.Invoke) {
      await bot.run(context)
    }
  })
})

// bot.js
module.exports.MyBot = class MyBot extends TeamsActivityHandler {
  constructor() {
      super()
      this.onTeamsMembersAddedEvent(async (membersAdded, teamInfo, turnContext, next) => {
        console.log('onTeamsMembersAddedEvent')
        await next()
      })
  }
}

Expected behavior

‘onTeamsMembersAddedEvent’ string output to console

Screenshots

If applicable, add screenshots to help explain your problem.

Additional context

this.onConversationUpdate works (by work, I mean I can see that the handler code is executed)

So does this.onMembersAdded.

Interestingly, using both this.onMembersAdded and this.onTeamsMembersAddedEvent at the same time, neither of them fire. When I remove, this.onTeamsMembersAddedEvent, this.onMembersAdded fires. this.onConversationUpdate always fires no matter what other handlers are registered.

[bug]

[mdrichardson]

Confirmed that I can repro this on v4.9.0, but not prior. Digging into this now.

[EricDahlvang]

Hi @oliviert

Thank you for reporting this!

We have a fix https://github.com/microsoft/botbuilder-js/pull/2237 which should be released in the next few days as v4.9.1