feat: Add support for macOS layered icons

[Sanlorng]

Support for using macOS layered icons (.icon directory) for both JVM and native application packaging.

This feature requires actool version >= 26.0

• A new layeredIconDir property is added to the compose.desktop.application.nativeDistributions.macOS and compose.nativeApplication.macOS DSLs.
• The actool from Xcode Command Line Tools is used to compile the .icon directory into an Assets.car file.
• The Assets.car file is included in the .app bundle resources.
• The Info.plist is updated with CFBundleIconName to reference the compiled asset.
• A check for a supported actool version is performed before compilation.
• New integration tests (testMacLayeredIcon, testMacLayeredIconRemove) are added to verify the functionality for both JVM and native targets.

Example

compose.desktop {
    application {
        nativeDistributions {
            macOS {
                layeredIconDir.set("Icon Path")
            }
        }
    }
}

Testing

Only verify the task behavior: compose:test-Gradle(9.0.0)-Agp(8.9.0) --tests org.jetbrains.compose.test.tests.integration.DesktopApplicationTest.testMacLayeredIcon

Only verify the task behavior: compose:test-Gradle(9.0.0)-Agp(8.9.0)** --tests org.jetbrains.compose.test.tests.integration.DesktopApplicationTest.testMacLayeredIconRemove

This should be tested by QA

Tickets

CMP-9083 Support macOS 26 layered icons

Release Notes

Features - Gradle Plugin

• Support for using macOS layered icons (.icon directory) for both JVM and native application packaging.

[kropp]

Hi, thank you for the contribution!
We will soon be requiring all PRs to have a linked issue in our tracker, I created one for this: CMP-9083 Support macOS 26 layered icons. It should be used for discussions around the newly added feature.