bug(form-field): Updating input value via `effect`+`FormControl` doesn't trigger label position calculation

[benelliott]

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

When updating a FormControl value inside a signal effect, the MatFormField floating label does not reposition under OnPush change detection unless ChangeDetectorRef.markForCheck() is called manually.

Reproduction

StackBlitz link: https://stackblitz.com/edit/ujogbvgu?file=src%2Fexample%2Fform-field-overview-example.ts
Steps to reproduce:

1. Update input via FormControl + effect
2. Observe that label position does not update unless ChangeDetectorRef.markForCheck() is invoked explicitly.

Expected Behavior

Using signals and effects, I expected not to have to call ChangeDetectorRef.markForCheck() for the label to float.

Actual Behavior

The label did not float when the control's value was set.

Environment

• Angular: 20.2.x
• CDK/Material: 20.2.x
• Browser(s): Chrome
• Operating System (e.g. Windows, macOS, Ubuntu): Windows

[crisbeto]

I tried a few combinations, but I'm not sure we can do much about it. The input already checks its value in ngDoCheck, but that won't fire if there's no change detections.