Mongoose does not automatically recreate index after reconnecting to different instance (calling .connection.close() then .connect())

[junzhengca]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Mongoose version

6.1.4

Node.js version

16.14.2

MongoDB server version

5.3

Description

I have a test suite for my personal project where I use mongoose to connect to a new instance of MongoDB for each test case. The actual setup is complex, but following is the idea:

describe('suite', () => {
     beforeEach(() => {
        const uri = getNewMongoUri();
        mongoose.connect(uri);
     });

     afterEach(() => {
        mongoose.connection.close();
     });


     it('case1'); //...
     it('case2'); //...
});

For one of the suites, I need to have text indexes built. However it seems like mongoose only automatically builds the text index when .connect is first called. It doesn't rebuild indexes for subsequent calls even if I am trying to connect to a completely different server.

I suggest adding this caveat to autoIndex option documentation. Or make index automatically rebuild for each .connect call prehaps?

There is a solution to this, which is to simply call ensureIndexes manually. But this behaviour just seemed weird and thought it could be a bug.

Steps to Reproduce

You just have to build a test suite or a script that does something similar to this (and make sure you use the index in case1 and case2:

describe('suite', () => {
     beforeEach(() => {
        const uri = getNewMongoUri();
        mongoose.connect(uri);
     });

     afterEach(() => {
        mongoose.connection.close();
     });


     it('case1'); //...
     it('case2'); //...
});

I used mongodb-memory-server, but also reproduceable using multiple installs directly on the OS.

Expected Behavior

Mongoose should automatically rebuild indexes after each .connect call if using different servers.