Migrations only seem to work for the 'admin' database

[dwhelan]

I am new to mongo and mongodb-migrations so I'm not sure I am doing something wrong but I noted the following:

Using the following migration file:

# 1-test.js

'use strict';

module.exports.id = "test";

module.exports.up = function (done) {
  this.log("up 1");
  done();
};

module.exports.down = function (done) {
  this.log("down 1");
  done();
};

and

# mm-config.json

{
  "url": "mongodb://localhost:27017/test",
  "directory": "migrations"
}

When I run the migration everything looks ok on the command line:

$ ./node_modules/.bin/mm migrate
   up 1
     Migration 'test': ok

But when I query the _migrations collection from mongo command line I get:

> db._migrations.find
2017-03-02T23:40:28.320-0500 E QUERY    [thread1] TypeError: db._migrations is undefined :
@(shell):1:1
>

The screenshot below also shows something odd from MongoDB Compass where the _migrations collection is not shown under the test db on the left panel yet shows up as a collection in the right panel. If I click on the _migrations collection in the right panel I get the error notification you see in the top right corner.

It seems like the collection is not created properly in the test db.

[droidpl]

I manage to make it work by using the following mm-config:

{
  "url": "mongodb://admin:adminPass@yourHost:yourPort/yourDb",
  "options": {
    "authSource": "admin"
  }
}

[nicolasmure]

In a mongo shell :

> db.getCollection("_migrations").find({})

is working, whereas

> db._migrations.find({})

is not.
Looks like it's a mongo bug : https://stackoverflow.com/questions/24309685/mongo-client-cant-access-collections-prefixed-with-an-underscore