model.convert() not called when accessing field via model.get()

[chaddjohnson]

I have the following model:

(function() {

  var fourDecimals = function(value, record) {
    return parseFloat(value.toFixed(4));
  }
  
  Ext.define('App.model.Stock', {
    extend: 'Ext.data.Model',
    fields: [
      {name: 'Symbol',             type: 'string'},
      {name: 'TradePrice',         type: 'float'},
      {name: 'Bid',                type: 'float'},
      {name: 'Ask',                type: 'float'},
      {name: 'Volume',             type: 'int'},
      {name: 'TodaysClose',        type: 'float'},
      {name: 'PreviousClose',      type: 'float'},
      {
        name: 'PriceChange',
        type: 'float',
        convert: function(value, record) {
          return parseFloat((record.get('TradePrice') - record.get('PreviousClose')).toFixed(4));
        }
      },{
        name: 'PercentPriceChange',
        type: 'float',
        convert: function(value, record) {
          return parseFloat((((record.get('TradePrice') / record.get('PreviousClose')) - 1) * 100).toFixed(2));
        }
      }
    ]
  });

})();

When I call do the following, the convert() function is not called for my model instance:

model.set('TradePrice', 12.34);
var priceChange = model.get('PriceChange');

Is this a bug?

[chaddjohnson]

This does work in Sencha Touch 2. When a field that a convert() function depends on is updated, the convert() function is called.

I found a workaround based on this blog post:

set: function(fieldName, newValue) {
  this.callParent(arguments);

  // Force recalculation of dependent fields.
  if (typeof fieldName == 'object' || fieldName == 'TradePrice' || fieldName == 'PreviousClose') {
    this.set('PriceChange');
    this.set('PercentPriceChange');
  }
}

I added that to the model.