Any Project Treble-supported device should be able to run a clean Generic System Image (or GSI) of a basic AOSP build. That’s the magic of Treble: all the supporting bits and customizations are separated from the GSI. This gave rise to enthusiasts being able to flash stock builds on skinned devices with (relative) ease.
However, it could also lead to testing Android versions early. Last year we got a treat; Google released the Android P Developer Previews for more than just Pixel and Nexus devices. This allowed certain phones to run the preview and give Google feedback.
With Treble being fairly common now, future test versions of Android could be released as GSIs rather than full builds. This would allow anyone with a Treble-supported device to give it a try. This would not guarantee perfect compatibility or usability, and wouldn’t be focused towards developers, but it would still give enthusiasts a nice treat while also gaining some important feedback. A Google Project Treble team member named Hung-ying Tyan had this to say at the Android Dev Summit:
“GSI is the central piece in Treble compliance. We feel that it has a lot more potential than that. We set out a goal to make GSI be more accessible and useful, not just for device makers but also the general public including app developers like you and even consumers. An important first step toward that goal is to make GSI available in AOSP. So for this, we have published pie-gsi in AOSP*. So now you can download and build pie-gsi today. We are also exploring ways to make future GSI available earlier than the release of next Android version. So you will be able to try out next Android version earlier over GSI. And at the same time we can also get early feedback from you, so the benefit is mutual. So please stay tuned for our further announcement on this.”
This isn’t an official announcement of test GSIs being released next year, but it is nice to see Google thinking about the rest of us. Hopefully this will come to fruition by the time Android Q is ready!