[deprecate] fallback lookup paths in ember-resolver

[gabrielcsapo]

Currently we have multiple fallback lookup paths in ember-resolver. As we continue to migrate towards a more strict future where imports are verified at build time (#454) it would be forward looking to remove non-strict lookups from ember-resolver to make codemods to migrate to;

• Strict Mode (Strict mode templates #496)
• the v2 addon format (v2 Addon Format (Embroider compatibility) #507)
• the slimming down the ember-cli build pipeline (Ember CLI build pipeline #578)
• strict service lookups (Registry APIs: deprecate micro-syntax; introduce replacement API #585)

It would benefit the ecosystem to remove fallback logic that enables many-to-one lookups in favor of a one-to-one mechanism.

The knock on effects of this would be having a supported solution to solve the following;

• Where does Pod resolution go and is supported?

An example of what this resolver would look like after removing all fallback lookup paths would be https://github.com/stefanpenner/ember-strict-resolver.

[rwjblue]

FWIW, I'm definitely in favor of a path forward here.

[gabrielcsapo]

@rwjblue I will work on an RFC to get a path forward planned out.

[wagenet]

Looks like we have an RFC so I'll close this ticket.