Virtual Packages

Description of the new feature / enhancement

For example, there are many OpenJDK flavors:

• Oracle.JDK.21
• EclipseAdoptium.Temurin.21.JDK
• Microsoft.OpenJDK.21
• Azul.Zulu.21.JDK
• BellSoft.LibericaJDK.21
• BellSoft.LibericaJDK.21.Full
• Amazon.Corretto.21

For packages that depend on OpenJDK 21, they do not have to tell the identity of the JDK that has already been installed in the system.
Winget packages that depend on OpenJDK try to install Microsoft.OpenJDK even though another JDK has already been installed.
We have to make them depend on another package that does not depend on a specific OpenJDK flavor instead of Microsoft.OpenJDK.

Proposed technical implementation details

• Provides a package named VirtualPackage.OpenJDK.21.SDK as an example
• Let the above packages provide it.
• If the user tries to install another package that depends on VirtualPackage.OpenJDK.21.SDK and has installed at least one of OpenJDK 21 flavors before, no additional packages are installed.
• If not installed yet, the one most recommended by the virtual package definition (Microsoft.OpenJDK.21?) will be installed.

A similar system has been available in Ubuntu. (no most recommended package feature is not implemented)

No files, tests, or entry points are named. Start by locating the existing package dependency and resolution behavior, then review how package metadata could represent virtual packages and providers. Done means packages can depend on the virtual OpenJDK 21 SDK, an installed compatible flavor satisfies that dependency, and a recommended flavor is selected when none is installed.