Template Deprecations (due to bind-attr and classNameBindings) with 1.13+.

[rwjblue]

The addon/templates/components/modal-dialog.hbs is triggering the following deprecations on Canary builds:

DEPRECATION: The `bind-attr` helper ('modules/ember-modal-dialog/templates/components/modal-dialog.hbs' @ L3:C11) is deprecated in favor of HTMLBars-style bound attributes.
        at isBindAttrModifier (/Users/rwjblue/src/work/cardstack/takeoff/bower_components/ember/ember-template-compiler.js:9692:24)
        at /Users/rwjblue/src/work/cardstack/takeoff/bower_components/ember/ember-template-compiler.js:9568:15
        at Walker.visit (/Users/rwjblue/src/work/foo-bar/bower_components/ember/ember-template-compiler.js:15489:7)
        at visitors.Program (/Users/rwjblue/src/work/foo-bar/bower_components/ember/ember-template-compiler.js:15499:16)
        at Walker.children (/Users/rwjblue/src/work/foo-bar/bower_components/ember/ember-template-compiler.js:15522:7)
        at Walker.visit (/Users/rwjblue/src/work/foo-bar/bower_components/ember/ember-template-compiler.js:15490:12)
        at visitors.BlockStatement (/Users/rwjblue/src/work/foo-bar/bower_components/ember/ember-template-compiler.js:15510:14)
        at Walker.children (/Users/rwjblue/src/work/foo-bar/bower_components/ember/ember-template-compiler.js:15522:7)
        at Walker.visit (/Users/rwjblue/src/work/foo-bar/bower_components/ember/ember-template-compiler.js:15490:12)
DEPRECATION: You're using legacy class binding syntax: classBinding="containerClassNamesString alignmentClass renderInPlaceClass container-class" @ 5:45 in (inline). Please replace with class=""
        at /Users/rwjblue/src/work/foo-bar/bower_components/ember/ember-template-compiler.js:10241:26
        at each (/Users/rwjblue/src/work/foo-bar/bower_components/ember/ember-template-compiler.js:10308:7)
        at /Users/rwjblue/src/work/foo-bar/bower_components/ember/ember-template-compiler.js:10226:7
        at Walker.visit (/Users/rwjblue/src/work/foo-bar/bower_components/ember/ember-template-compiler.js:15489:7)
        at visitors.Program (/Users/rwjblue/src/work/foo-bar/bower_components/ember/ember-template-compiler.js:15499:16)
        at Walker.children (/Users/rwjblue/src/work/foo-bar/bower_components/ember/ember-template-compiler.js:15522:7)
        at Walker.visit (/Users/rwjblue/src/work/foo-bar/bower_components/ember/ember-template-compiler.js:15490:12)
        at visitors.BlockStatement (/Users/rwjblue/src/work/foo-bar/bower_components/ember/ember-template-compiler.js:15510:14)
        at Walker.children (/Users/rwjblue/src/work/foo-bar/bower_components/ember/ember-template-compiler.js:15522:7)

[lukemelia]

@rwjblue what is the best pattern for addons supporting multiple versions of Ember with respect to this kind of thing? Should we have separate versions of the templates and conditionally use the correct one?

[rwjblue]

I can see two potential solutions (likely there are more):

1. Maintain two template files, and implement an treeFor that returns the right one.
2. Maintain two branches.

Clearly 2 is not great...

[lukemelia]

@rwjblue looking into your suggested solution "1" now, and realized that (unless I missed something) I don't know the Ember version an app is using from within the addon.

[lukemelia]

@rwjblue Also found that ember-cli was missing the treeForAddonTemplates hook, which is where we would need to customize. Added it here: ember-cli/ember-cli#4159

[lukemelia]

Working on a fix here: #41