bug(cdk/overlay): attach() and detach are not working in zoneless apps

[javiermarinros]

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

No response

Description

The Overlay attach() and detach() methods are relying on the ngZone.onStable observable that is never invoked using the new provideZonelessChangeDetection app provider.

The related actual code:

  // Update the position once the zone is stable so that the overlay will be fully rendered
    // before attempting to position it, as the position may depend on the size of the rendered
    // content.
    this._ngZone.onStable.pipe(take(1)).subscribe(() => {
      // The overlay could've been detached before the zone has stabilized.
      if (this.hasAttached()) {
        this.updatePosition();
      }
    });

Expected Behavior

Overlays to attach and position themselves in zoneless aplications

Actual Behavior

Overlay is created but not positioned and not visible

Environment

• Angular: 17.1
• CDK/Material: 17.1

[atscott]

Indeed, this is the case everywhere in the repo that uses NgZone APIs. This particular one has a WIP fix here #28332