Clarify default attribute overriding with mixins

[ZhihaoJia]

The mixin API documentation has a section on overriding defaults:

The attributes method is available to both component and mixin modules. When used with mixins it will not overwrite attributes already defined in the component module.

My impression was that default attributes defined in components would never be overridden by default attributes defined in mixins. However, the opposite seems to be the case for me:

module.exports = withCookies;

function withCookies() {
  this.attributes({
    wantsCookies: false
  });
}

module.exports = flight.component(cookieMonster, withCookie);

function cookieMonster() {
  this.attributes({
    wantsCookies: true
  });

  this.after('initialize', function initialize() {
    console.log(this.attr.wantsCookies); // false
  });
}

If I want the component's default attribute to take precedence over the mixin's, I need to change the order they are passed into flight.component():

module.exports = flight.component(withCookie, cookieMonster);

function cookieMonster() {
  this.attributes({
    wantsCookies: true
  });

  this.after('initialize', function initialize() {
    console.log(this.attr.wantsCookies); // true
  });
}

Is this the intended behavior? If so, can we clarify this in the documentation?

[giuseppeg]

@ZhihaoJia that's correct.
The old this.defaultAttrs would fail when the second mixin had an attribute already defined on the previous mixins:

Uncaught Error: utils.push attempted to overwrite "wantsCookies" while running in protected mode

When the docs were updated Nicolas forgot to invert the order I guess.

Here is the relevant code