there are no spans for queries w/out exec() for mongoose 5.6.3

Describe the bug The library does not automatically creates span if there is no explicit exec() function call on query object.

Mongoose uses native Promise.

mongoose.Promise = global.Promise;

Following code snippet is instrumented perfectly and span is created

async function test() {
    const result = await Model.find().exec();
    console.log(result);
}

This code snippet cannot be automatically instrumented (span cannot be created)

async function test() {
    const result = await Model.find();
    console.log(result);
}

Mongoose automatically calls exec when then is called https://github.com/Automattic/mongoose/blob/5.6.3/lib/query.js#L4297-L4299

To Reproduce

Run code snippets below in your app. If you run with explicit exec call then span is created otherwise it won’t.

Expected behavior

Span should be created w/ and w/out explicit exec function call.

Environment (please complete the following information)

• OS: Mac OS 10.15.1
• Node.js version: 12.13.0
• APM Server version: 7.4.0
• Agent version: 3.1.0

How are you starting the agent? (please tick one of the boxes)

• Calling agent.start() directly (e.g. require('elastic-apm-node').start(...))
• Requiring elastic-apm-node/start from within the source code
• Starting node with -r elastic-apm-node/start

[evgeni-k]

Thank you for your reply. Probably it makes sense to update docs to explicitly highlight that fact about custom thenable.

Feel free to close the ticket.

[Qard]

Yep, I fixed the issue in V8 a few months ago. It’s in Node.js 14.x. Still waiting on the backport to land in 12.x.