📦 Compose Desktop Linux Package Deps (DEB)

Small Gradle plugin for Compose Desktop that automatically adds Debian Depends: to the .deb generated by jpackage. Can write StartupWMClass into .desktop files to fix dock/taskbar icons (fixes JBR-9114).

🛠 Requirements

• 🐧 Debian/Ubuntu build env with dpkg-deb → sudo apt-get install dpkg-dev
• 💻 Using Compose Multiplatform packaging (packageDeb / packageReleaseDeb)

🚀 Quick start

// build.gradle.kts
plugins {
    id("io.github.kdroidfilter.compose.linux.packagedeps") version "<version>"
}

linuxDebConfig {
    // add dependencies to DEBIAN/control
    debDepends.set(listOf("libqt5widgets5t64", "libx11-6"))

    // if you want to add dependencies with alternatives for compatibility with older OSes, add them like this:
    debDepends.set(
        listOf(
            "libqt5core5t64 | libqt5core5a",
            "libqt5gui5t64 | libqt5gui5",
            "libqt5widgets5t64 | libqt5widgets5",
        )
    )
    // set StartupWMClass to fix dock/taskbar icon
    startupWMClass.set("MainClassKt")

    //for Ubuntu 24 t64 dependencies compatibility with older OSes, see below Under Known jpackage issue: Ubuntu t64 transition
    enableT64AlternativeDeps.set(true)
}

Build as usual:

./gradlew packageDeb
# or
./gradlew packageReleaseDeb

⚙️ What it does

• 🔍 Finds the jpackage-generated .deb
• ➕ Adds/merges a Depends: line in DEBIAN/control (de-duplicates)
• 🖊 Writes StartupWMClass= into .desktop files if configured
• 📦 Rebuilds the .deb

🐞 Troubleshooting

• ❌ dpkg-deb not found → sudo apt-get install dpkg-dev
• 📂 No .deb found → run ./gradlew packageDeb first
• 🖼 Dock icon not matching → set startupWMClass (e.g., "MainClassKt")

❗ Known jpackage issue: Ubuntu t64 transition

There is an upstream jpackage quirk related to the Ubuntu/Debian time_t (t64) transition:

• When you build on Ubuntu 24.04 (or newer), jpackage resolves and injects dependencies as they exist on the build host. It writes t64 package names (for example: libasound2t64, libpng16-16t64) into the Depends field. Those packages don’t exist on Ubuntu 22.04, so the .deb won’t install there.
• Conversely, if you build on Ubuntu 22.04, the produced .deb depends on non‑t64 packages (libasound2, libpng16-16). On Ubuntu 24.04, the system prefers the t64 variants, which can cause incompatibility.

How this plugin helps

• Set linuxDebConfig.enableT64AlternativeDeps = true to make the plugin rewrite the existing Depends line generated by jpackage into alternatives that work on both sides:
  • libasound2t64 (and optional version) → libasound2t64 (same version) | libasound2
  • libpng16-16t64 (and optional version) → libpng16-16t64 (same version) | libpng16-16
  • libasound2 (and optional version) → libasound2t64 (same version) | libasound2
  • libpng16-16 (and optional version) → libpng16-16t64 (same version) | libpng16-16
• Only the dependencies already present in DEBIAN/control (added by jpackage) are rewritten. Entries you add via debDepends are not modified.

Examples

• Before (built on Ubuntu 24.04): Depends: libasound2t64, libpng16-16t64, …
• After (with enableT64AlternativeDeps=true): Depends: libasound2t64 | libasound2, libpng16-16t64 | libpng16-16, …

📜 License

MIT — see LICENSE.