Test a stable release update

Ubuntu has a six month cycle for releases. This means that we work for six months updating software, adding new features and making sure that it all works consistently together when it’s integrated into the operating system, and then we release it. Once we make a release, it is considered stable and then we almost exclusively add to that release critical bug fixes and patches for security vulnerabilities. The exceptions are just a few, and are for software that’s important for Ubuntu and that we want to keep up-to-date with the latest features even in stable releases.

These bug fixes, security patches and exceptional new features require a lot of testing, because right after they are published they will reach all the Ubuntu users that are in the stable release. And we want the release to remain stable, never ever introduce a regression that will make those users unhappy.

We call all of them Stable Release Updates, and we test them in the proposed pocket of the Ubuntu archive. This is obviously not enabled by default, so the brave souls that want to help us testing the changes in proposed need to enable it.

Before we go on, I would recommend to test SRUs in a virtual machine. Once you enable proposed following this guide you will get constant and untested updates from many packages, and these updates will break parts of your system every now and then. It’s not likely to be critical, but it can bother you if it happens on the machine you need to do your work, or other stuff. And if somebody makes a mistake, you might need to reinstall the system.

You will also have to find a package that needs testing. Snapcraft is one of the few exceptions allowed to land in a stable release every week. So lets use it as an example. Lets say you want to help us testing the upcoming release of snapcraft in Ubuntu 16.04.

With your machine ready and before enabling proposed, install the version already released of the package you want to test. This way you’ll test later an update to the newer version, just what a normal user would get once the update is approved and lands in the archive. So in a terminal, write:

  $ sudo apt update
  $ sudo apt install snapcraft

Or replace snapcraft with whatever package you are testing. If you are doing it just during the weekend after I am writing this, the released version of snapcraft will be 2.23. You can check it with:

  $ dpkg -s snapcraft | grep Version
  Version: 2.23

Now, to enable proposed, open the Ubuntu Software application, and select Software & Updates from the menu in the top of the window.

From the Software & Updates window, select the Developer Options tab. And check the item that says Pre-released updates.

This will prompt for your password. Enter it, and then click the Close button. You will be asked if you want to reload your sources, so yes, click the Reload button.

Finally try to upgrade. If there is a newer version available in the proposed pocket for the packet you are testing, now you will get it.

  $ sudo apt install snapcraft
  $ dpkg -s snapcraft | grep Version
  Version: 2.24

Every time there is a proposed update, the package will have corresponding SRU bugs with the tag “verification-needed”. In the case of snapcraft this weekend, this is the bug for the 2.24 proposed update: https://bugs.launchpad.net/ubuntu/+source/snapcraft/+bug/1650632

The SRU bugs will have instructions about how to test that the fix or the new features released are correct. Follow those steps, and if you are confident that they work as expected, change the tag to “verification-done”. If you find that the fix is not correct, change the tag to “verification-failed”. In case of doubt, you can leave a comment in the bug explaining what you tried and what you found.

You can read more about SRUs in the Stable Release Updates wiki page, and also in the wiki page explaining how to perform verifications. This last page includes a section to find packages and bugs that need verification. If you want to help the Ubuntu community, you can just jump in and start verifying some of the pending bugs. It will be highly appreciated.

If you have questions or find a problem, join us in the Ubuntu Rocket Chat.