Codemod for template-only-glimmer-components doesn't support Addons

[elwayman02]

It appears that the codemod implementation only runs against components in the app/ directory, which will not work for addons, which store their components in the addon/ directory and may not re-export them at all (since doing so is dangerous and a bad pattern). In order for addons to successfully enable this feature, the codemod needs to be able to create backing classes for addon components.

https://github.com/emberjs/ember-optional-features/blob/master/features/template-only-glimmer-components.js#L55

[elwayman02]

Following up on discussion with @chancancode to capture some pieces we figured out:

• This isn't necessarily a concern of ember-optional-features, which was intended to be used by app consumers
• Addons don't generally have template-only components if they are following the re-export pattern in their app/ directory
• This codemod is necessary for addons that expect to use Wall St syntax for namespaced component invocation (and will be useful for template imports as well)

Conclusion: It may be better for this codemod to live as a separate project in ember-codemods rather than as part of this project.

[elwayman02]

Coming full circle on this.

@rwjblue implemented the codemod to fix this here: rwjblue/ember-holy-futuristic-template-namespacing-batman-codemod#58

However, there is a related issue that I believe does impact this project. If you enable template-only-glimmer-components in an addon, it does not create backing classes for template-only components in tests/dummy/templates/components, which is a perfectly valid use-case for addons.

[rwjblue]

which is a perfectly valid use-case for addons

Ya, agreed.