bug(mat slider): Thumb position not updating after max value changes

[mark-langer]

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

v16

Description

If the max attribute of the slider is lower than the value bound to the slider's thumb, the position is limited to the max value ✅
But if max is set to a higher value again which would allow the bound value again, the thumb doesn't update.

Reproduction

Reproduction on the Angular Material demo site:

Expected Behavior

The thumb is always positioned correctly depending on the inputs of min, max and value/ngModel.

Actual Behavior

The thumb is positioned based on the lowest maxValue ever provided. It only updates as soon as the input binding for value changes.

Environment

• Angular: 20.1.2
• CDK/Material: 20.1.2
• Browser(s): Firefox 140.0.4, Chrome 138.0.7204.158
• Operating System (e.g. Windows, macOS, Ubuntu): macOS

[crisbeto]

We don't restore the value when the max changes because we'd have to store it and then know whether it's intended to restore it or not. E.g. it can also be confusing for the user if the max changes and it suddenly snaps back to some older value.

[mark-langer]

Thanks for the quick reply!

Wouldn't it make sense though that the ngModel binding is always reflected? Right now, it isn't. If the user had interacted with the component in the meantime, I can totally see your point. But right now, I feel it's confusing that the ngModel binding is not honored even though the max value will allow it in the end.