Which @angular/* package(s) are the source of the bug?

compiler

Is this a regression?

Yes, works in 22.0.8, broken in 22.2.4 and 22.3.0-next.3. Came with #68846

Description

Hit this in my ui lib, had to move component inputs to separate variable

[style.--x] compiles to key --%NS%x, but static style="--x: red" and [style]="'--x: red'" keep --x. Styling priority looks values up by key, so these never mathc and binding stops seeing value of same name. [style.color] is not affected. No provideCssVarNamespacing() needed to hit this

• host binding [style.--x] now overwrites value author set on component element, before author won
• undefined no longer falls back to static or [style] value, element ends up without --x

With provideCssVarNamespacing('ns') both stay on element: --x: red; --ns_x: blue

Please provide a link to a minimal reproduction of the bug

@Component({ selector: 'my-cmp', template: '', host: { '[style.--x]': 'v' } })
class MyCmp {
  @Input() v?: string;
}

@Component({ selector: 'app-root', imports: [MyCmp], template: `<my-cmp style="--x: red" v="blue" />` })
class App {}

getAttribute('style') on my-cmp: --x: red in 22.0.8, --x: blue in 22.2.4 and 22.3.0-next.3

Please provide the exception or error you saw

None

Please provide the environment you discovered this bug in (run ng version)

@angular/core 22.0.8, 22.2.4 and 22.3.0-next.3, Chromium, JIT

Anything else?

Compliance golden style_bindings/css_custom_properties.js shows same split: --camel-case in consts, --%NS%camelCase in ɵɵstyleProp