3.28: Awaiting async relationships does not work anymore

[Turbo87]

Reproduction

• clone https://github.com/rust-lang/crates.io/pull/3852
• yarn install
• yarn start:live
• http://localhost:4200/tests/?mirageLogging&filter=visiting%20a%20crate%20page%20from%20the%20front%20page
• observe that versions = await crate.get('versions'); resolves before the network request has been performed

Description

Just like in previous Ember Data releases I expected to be able to await async relationships to be able to wait until the content has loaded before continuing, but this appears to have broken with v3.28 by resolving before the network request has resolved.

Versions

Run the following command and paste the output below: yarn list ember-source && yarn list ember-cli && yarn list --pattern ember-data.

❯ yarn list ember-source && yarn list ember-cli && yarn list --pattern ember-data
yarn list v1.22.4
warning Filtering by arguments is deprecated. Please use the pattern option instead.
└─ ember-source@3.28.0
✨  Done in 1.21s.
yarn list v1.22.4
warning Filtering by arguments is deprecated. Please use the pattern option instead.
└─ ember-cli@3.28.0
✨  Done in 0.90s.
yarn list v1.22.4
├─ @ember-data/adapter@3.28.0
├─ @ember-data/canary-features@3.28.0
├─ @ember-data/debug@3.28.0
├─ @ember-data/model@3.28.0
├─ @ember-data/private-build-infra@3.28.0
├─ @ember-data/record-data@3.28.0
├─ @ember-data/rfc395-data@0.0.4
├─ @ember-data/serializer@3.28.0
├─ @ember-data/store@3.28.0
├─ babel-plugin-ember-data-packages-polyfill@0.1.2
└─ ember-data@3.28.0
✨  Done in 0.90s.

[igorT]

Thanks for the detailed issue report, it seems like a few people have run into this, we are working on a fix in https://github.com/emberjs/data/pull/7691