bug(COMPONENT): ThemePalette for Material 3

[seneric]

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

I reopen the issue (#28902) because you asked me about "a mixin for backwards compatability".

I know the "backwards compatability" mixin I use it !

But when you want to develop a new full M3 compatability web site with the actual "ThemePalette" type it is impossible !

Reproduction

color.ts contain
`/** Possible color palette values. */

export type ThemePalette = 'primary' | 'accent' | 'warn' | undefined;`

Expected Behavior

ThemePalette Marerial 3 compatible

Actual Behavior

ThemePalette only Marerial 2 compatible

Environment

• Angular: 17.3.x
• CDK/Material: 17.3.x
• Browser(s): all
• Operating System (e.g. Windows, macOS, Ubuntu): all

[mmalerba]

The [color] input that many components have isn't supported in M3. It will still apply CSS classes (e.g. .mat-primary) but M3 doesn't target any styles at those classes (unless you add the backwards compatibility mixin).

Instead M3 offers a new Sass-based API for applying color variants, you can read about it here: https://material.angular.io/guide/material-3#using-component-color-variants. This allows you to apply the color variant styles to a selector of your choosing. The advantage of this API is that you don't have to pay for styles you're not actually using. (By contrast, the [color] input API in M2 had to generate styles for every variant of every component regardless of whether you actually used them in your app.)

[seneric]

So you have to modify this documentaion: https://material.angular.io/guide/material-3
"Using component color variants" section: A number of components have a color input property that allows developers to apply different color variants of the component. When using an M3 theme, this input still adds a CSS class to the component (e.g. .mat-accent).

This is impossible with the actual "ThemePalette". Because it miss Secondary, Tertiary and Error entries