EmberData | Deprecate Model Reopen
reopen to alter clases extending
reopen restricts the ability of EmberData to design better primitives that maintain
@ember-data/model, and is a footgun that leads to confusing incorrect
states for users that utilize it.
reopen method on
Model will be overwritten to provide a deprecation which
once resolved or after the deprecation lifecycle completes will result in
an error when used in dev and silently no-oping in production. This deprecation will target
5.0 and not be
enabled sooner than
4.1 though it may come available before that.
How we teach this
This is best taught through a deprecation guide. Users using
reopen to test multiple
configurations in their test suite should instead extend and register a new model each time.
reopen to modify a class immediately after creating it should also refactor
reopen to modify a class dynamically at runtime should refactor to either register
new model types or (better) utilize a megamorphic solution such as ember-m3 to achieve their needs.
In all cases, using
reopen after a class instance for a record has already been created has always
resulted in at least minor and potentially major errors in application state.
Test suites, including EmberData's own, that make use of
reopen are often "order dependent" in order
for the test suite to pass, and refactoring them can sometimes be a difficult exercise in determining
which tests had modified the class to achieve the model shape needed by another test. In general though
the drawbacks here are small given the widespread adoption of class syntax and growing adoption of octane
reopenand wait to replace
@ember-data/modelin it's entirety. This alternative would prevent us from providing custom decorators not extending from
computedand limit potential build tools allowing users to optimize existing usage of EmberData.
reopen. Because we cannot build custom decorators and support
reopenwithout asking for
emberto make available to use private APIs I do not think we should wait for Ember here. This RFC does not preclude or force Ember to deprecate reopen more broadly.