emberjs/ember.js — pull request #2284 by stefanpenner (2013-03-16 14:39:34+00:00)
Title: computed.alias gets optional readOnly flag

Aliasing properties is powerful, to some peoples
surprise they alias both set and get. Usually this
is the behaviour one wants but sometimes, as
https://github.com/emberjs/data/commit/7b88a92c090dddf2d554fb4d4095322f9eef8a59
suggests, this behaviour is not at all wanted.

When the read only flag is flipped on, a set will
throw and Error. Preventing the set, and providing
useful feedback.