ember.js: Error in 2.7.0 but not 2.6.0: Uncaught Error: Assertion Failed: Attempted to register a view with an id already in use: null

Updated

The bug is that since elementId is now conditionally initialized based on tagName (was this way in 1.12 and below), if the tagName is inherited as ‘’ and you set it again post this._super(...arguments);, then elementId === null but since tagName is now set to not be "" then when the view is registered, it will be registered as "null" causing problems if you render more than one.

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When using Ember 2.7.0

When there are two instances of the same component used in a template the error of Uncaught Error: Assertion Failed: Attempted to register a view with an id already in use: null is thrown.

If the component is used in a parent route’s template as well as the child’s, when navigating away these deprecations are thrown:

DEPRECATION: A property of <regressionDemo@view:-outlet::ember413> was modified inside the didInsertElement hook. You should never change properties on components, services or models during didInsertElement because it causes significant performance degradation. [deprecation id: ember-views.dispatching-modify-property]
        at logDeprecationStackTrace (http://localhost:4200/assets/vendor.js:16676:19)
        at HANDLERS.(anonymous function) (http://localhost:4200/assets/vendor.js:16783:7)
        at raiseOnDeprecation (http://localhost:4200/assets/vendor.js:16706:12)
        at HANDLERS.(anonymous function) (http://localhost:4200/assets/vendor.js:16783:7)
        at invoke (http://localhost:4200/assets/vendor.js:16799:7)
        at deprecate (http://localhost:4200/assets/vendor.js:16767:32)
        at Object.deprecate (http://localhost:4200/assets/vendor.js:29639:37)
        at Class.exports.default._emberMetalMixin.Mixin.create._Mixin$create.scheduleRevalidate (http://localhost:4200/assets/vendor.js:54123:22)
        at http://localhost:4200/assets/vendor.js:27891:32
7ember.debug.js:6568 DEPRECATION: A property of <regressionDemo@view:-outlet::ember413> was modified inside the didInsertElement hook. You should never change properties on components, services or models during didInsertElement because it causes significant performance degradation. [deprecation id: ember-views.dispatching-modify-property]
        at logDeprecationStackTrace (http://localhost:4200/assets/vendor.js:16676:19)
        at HANDLERS.(anonymous function) (http://localhost:4200/assets/vendor.js:16783:7)
        at raiseOnDeprecation (http://localhost:4200/assets/vendor.js:16706:12)
        at HANDLERS.(anonymous function) (http://localhost:4200/assets/vendor.js:16783:7)
        at invoke (http://localhost:4200/assets/vendor.js:16799:7)
        at deprecate (http://localhost:4200/assets/vendor.js:16767:32)
        at Object.deprecate (http://localhost:4200/assets/vendor.js:29639:37)
        at Class.exports.default._emberMetalMixin.Mixin.create._Mixin$create.scheduleRevalidate (http://localhost:4200/assets/vendor.js:54123:22)
        at http://localhost:4200/assets/vendor.js:27891:32
ember.debug.js:6568 DEPRECATION: A property of <regressionDemo@view:-outlet::ember413> was modified inside the didInsertElement hook. You should never change properties on components, services or models during didInsertElement because it causes significant performance degradation. [deprecation id: ember-views.dispatching-modify-property]
        at logDeprecationStackTrace (http://localhost:4200/assets/vendor.js:16676:19)
        at HANDLERS.(anonymous function) (http://localhost:4200/assets/vendor.js:16783:7)
        at raiseOnDeprecation (http://localhost:4200/assets/vendor.js:16706:12)
        at HANDLERS.(anonymous function) (http://localhost:4200/assets/vendor.js:16783:7)
        at invoke (http://localhost:4200/assets/vendor.js:16799:7)
        at deprecate (http://localhost:4200/assets/vendor.js:16767:32)
        at Object.deprecate (http://localhost:4200/assets/vendor.js:29639:37)
        at Class.exports.default._emberMetalMixin.Mixin.create._Mixin$create.scheduleRevalidate (http://localhost:4200/assets/vendor.js:54123:22)
        at Class.setOutletState (http://localhost:4200/assets/vendor.js:27941:14)

When using Ember 2.6.0

These problems do not occur.

How to reproduce

I have created an application recreating this setup, located at https://github.com/notmessenger/regressionDemo If you change the Ember version to 2.6.0 the errors will then go away.