[MaterialButton] iconSize does not always match Material 3 specs

[seadowg]

Description: The Material 3 MaterialButton style Widget.Material3.Button.OutlinedButton.Icon does not specify an iconSize so this remains at the default wrap_content rather than the 18dp value defined in the Material 3 spec.

Expected behavior: Material 3 Button .Icon styles (or their parents) should all specify a default app:iconSize of 18dp.

Source code:

<com.google.android.material.button.MaterialButton
    style="@style/Widget.Material3.Button.OutlinedButton.Icon"
    app:icon="@drawable/ic_save"/>

The icon displayed by this button will be as large as the icon itself (due to MaterialButton using wrap_content for iconSize by default).

Material Library version: 1.7.0

[afohrman]

Thanks so much for reporting this, @seadowg. MaterialButtons should all have a default 18dp iconSize, but it looks like some MaterialButton styles don't inherit from the base Widget.Material3.Button style where that default iconSize is set. We need to either simplify M3 button style inheritance so that all styles inherit from Widget.Material3.Button and the default iconSize is used for all M3 button styles, or just add iconSize to Widget.Material3.Button.TextButton so that all button styles that inherit from Widget.Material3.Button.TextButton get that iconSize.