Defaults corruption

[cha0s]

Any defaults that contain a reference will be corrupted when a value is set into the corresponding attribute. Here's a short example:

{Schema} = require 'jugglingdb'

schema = new Schema require('jugglingdb/lib/adapters/memory'), {}

Test = schema.define 'Test',

    attribute:
        type: Schema.JSON
        default: {}

test = new Test()

test.attribute['foo'] = 'bar'

test2 = new Test()

throw new Error "Corrupted default" if test2.attribute['foo'] is 'bar'

...and in JS in case you hate Coffee:

(function() {
  var Schema, Test, schema, test, test2;

  Schema = require('jugglingdb').Schema;

  schema = new Schema(require('jugglingdb/lib/adapters/memory'), {});

  Test = schema.define('Test', {
    attribute: {
      type: Schema.JSON,
      "default": {}
    }
  });

  test = new Test();

  test.attribute['foo'] = 'bar';

  test2 = new Test();

  if (test2.attribute['foo'] === 'bar') {
    throw new Error("Corrupted default");
  }

}).call(this);

You can see in model.js that the getDefault function simply returns the default, which in the case of Schema.JSON (and possibly others) is a reference to the default object. This means that when a key is set in a property of a specific model instance, the change will propagate up to (and corrupt) the default object.

I'm not sure what the correct fix is. I am working around this in my own code by using the function version of default, and returning an empty object from a simple closure.

[anatoliychakkaev]

Make it function that returns object.

On 5 April 2014 08:30, Ruben Rodriguez [email protected] wrote:

Any defaults that contain a reference will be corrupted when a value is
set into the corresponding attribute. Here's a short example:

{Schema} = require 'jugglingdb'
schema = new Schema require('jugglingdb/lib/adapters/memory'), {}
Test = schema.define 'Test',

attribute:
    type: Schema.JSON
    default: {}

test = new Test()
test.attribute['foo'] = 'bar'
test2 = new Test()
throw new Error "Corrupted default" if test2.attribute['foo'] is 'bar'

...and in JS in case you hate Coffee:

(function() {
var Schema, Test, schema, test, test2;

Schema = require('jugglingdb').Schema;

schema = new Schema(require('jugglingdb/lib/adapters/memory'), {});

Test = schema.define('Test', {
attribute: {
type: Schema.JSON,
"default": {}
}
});

test = new Test();

test.attribute['foo'] = 'bar';

test2 = new Test();

if (test2.attribute['foo'] === 'bar') {
throw new Error("Corrupted default");
}
}).call(this);

You can see in model.jshttps://github.com/cha0s/promised-jugglingdb/blob/master/lib/model.js#L109that the getDefault function simply returns the default, which in the case
of Schema.JSON (and possibly others) is a reference to the default object.
This means that when a key is set in a property of a specific model
instance, the change will propagate up to (and corrupt) the default object.

I'm not sure what the correct fix is. I am working around this in my own
code by using the function version of default, and returning an empty
object from a simple closure.

Reply to this email directly or view it on GitHubhttps://github.com//issues/393
.

[randunel]

This is an excerpt from docs/schema.md:

var User = schema.define('User', {
    email: { type: String, limit: 150, index: true },
    password: { type: String, limit: 50 },
    birthDate: Date,
    registrationDate: {
        type: Date,
        default: function () { return new Date }
    },
    activated: { type: Boolean, default: false }
}, {
    table: 'users'
});

Take a look at default: function() {return new Date}

[cha0s]

@1602 Yeah, I did use the callback version.

@randunel Yeah, that one is a bit different because semantically it matters when you create a Date object.

How do you guys feel about making a special note about this in the docs? I could see other people running into this.

[randunel]

Yup, makes sense.