Data cache leaking?

[bramus]

Consider these models:

var Movie = db.define('movies', {
    id: Number,
    title: String,
    year: Number,
    rating: Number
});

var Genre = db.define('genres', {
    id: Number,
    title: String
});

Movie.hasMany('genres', Genre); // link genres, no autofetch

When calling this piece of code (I'll name it snippet A, as I'll refer back to it later on) ...

Movie.find({}, 100, function(err, movies) {
    // ...
}

... and then outputting movies on screen in the callback you get this dataset for example:

[
    {
        "id": 1,
        "title": "Futurama: Bender's Big Score",
        "year": 2007,
        "rating": 7.6
    },
    {
        "id": 2,
        "title": "Futurama: The Beast with a Billion Backs",
        "year": 2008,
        "rating": 7.2,
    }
]

When then calling a different URL on the app to fetch one single movie with genres ...

Movie.get(id, function(err, movie) {
    movie.getGenres(function(err, genres) {
        movie.genres = genres;
        // ...
    }
});

... we get back this when outputting movie from within the second callback

{
    "id": 1,
    "title": "Futurama: Bender's Big Score",
    "year": 2007,
    "rating": 7.6,
    "genres": [
        {"id": 1, "title: "Animation"},
        {"id": 2, "title: "Action"},
        {"id": 3, "title: "Comedy"}
    ]
}

Now comes the kicker: when now visiting the URL that executes snippet A again, you get back this dataset:

[
    {
        "id": 1,
        "title": "Futurama: Bender's Big Score",
        "year": 2007,
        "rating": 7.6,
        "genres": [
            {"id": 1, "title: "Animation"},
            {"id": 2, "title: "Action"},
            {"id": 3, "title: "Comedy"}
        ]
    },
    {
        "id": 2,
        "title": "Futurama: The Beast with a Billion Backs",
        "year": 2008,
        "rating": 7.2,
    }
]

As you can see the genres mysteriously appear here now, which shouldn't be the case.

[dresende]

Hmmm... interesting.. I never thought about that. I try to use singletons when fetching data to avoid having 2 instances in memory and changing one and the other getting outdated.. the only way of avoiding this is having an option to disable singletons.

[dresende]

You can now do this for the entire Model or for a specific Model.get() or Model.find().

Examples:

var Person = db.define('person', {
    // ...
}, {
    cache: false // disable globally
});

Person.find({ ... }, { cache: false }, cb); // disable locally

I still have to check the associations but I think that's simple now.

[dresende]

Associations for now are affected by the global parameter.

[bramus]

Tested and verified, thanks!