[Bug] 2.3.2 broke `observes` modifier

🐞 Bug description

With the latest version of ember-concurrency the observes modifier stopped working.

import Model, { attr } from '@ember-data/model';
import { inject as service } from '@ember/service';
import { task } from 'ember-concurrency';

export default class Parking extends Model {
  @service store;

  @attr('array', { defaultValue: () => [] }) carIds;

  // This tasks should perform everytime `cardIds` changes.
  @task({
    observes: 'carIds.[]',
    drop: true,
  })
  *loadCarsTask() {
    // ...
  }
}

import Component from '@glimmer/component';
import { action, set } from '@ember/object';

export default class ParkingBox extends Component {
  @action
  onCarChange(cars) {
    const { parking } = this.args;
    const cardIds = cars.map(({ id }) => parseInt(id));

    set(parking, 'cardIds', cardIds);
  }
}

😕 Actual Behavior

loadCarsTask isn’t performing when carIds changes.

🤔 Expected Behavior

loadCarsTask should perform everytime cardIds changes.

🌍 Environment

• ember-concurrency 2.3.2
• ember-source 4.6.0
• ember-data 4.2.0

[machty]

@esbanarango Yes, I think it is probably not a good idea for us to try and fix this for the new API as it would add further complexity to the EC codebase to accommodate a deprecated pattern.

[machty]

Fixed in v2.3.4