fix(NODE-5106): prevent multiple mongo client connect()s from leaking topology

[clemclx]

fix(NODE-5106): Add MongoClient connect lock mechanism to avoid topology leak

Description

Related to the ticket opened here : https://jira.mongodb.org/browse/NODE-5106
As mentionned in the issue, not test provided because atm a test cannot be performed according to the beforeHooks awaiting the MongoClient connect.

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• Ran npm run check:lint script
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[addaleax]

This generally seems like the right thing to do, but I think you'll need to add a test for this. Somebody from the team can probably confirm.

You probably don't need all the complexity of the resource_clean_up.test.ts file, I think you could just ensure that e.g. when you call client.connect() twice in the same tick, you'll stil only get one open event on the MongoClient.

[clemclx]

Yes I clarified in the ticket why I did not add a test.
Maybe it is not necessary to add it to the resource_clean_up.test.ts yes, I let someone of the team with a much better knowledge of the code base decide where it belongs.

I remain available ☺️

[nbbeeken]

Thanks so much @clemclx really appreciate your help with this! I've got some ideas to improve the testing a bit here:

[clemclx]

Hey @nbbeeken,
I updated the PR according to your review, thanks !
Let me know if I can be useful for something else.