git-repo/docs/release-process.md

repo release process

This is the process for creating a new release of repo, as well as all the related topics and flows.

[TOC]

Schedule

There is no specific schedule for when releases are made. Usually it's more along the lines of "enough minor changes have been merged", or "there's a known issue the maintainers know should get fixed". If you find a fix has been merged for an issue important to you, but hasn't been released after a week or so, feel free to contact us to request a new release.

Release Freezes

We try to observe a regular schedule for when not to release. If something goes wrong, staff need to be active in order to respond quickly & effectively. We also don't want to disrupt non-Google organizations if possible.

We generally follow the rules:

• Release during Mon - Thu, 9:00 - 14:00 US PT
• Avoid holidays
  • All regular US holidays
  • Large international ones if possible
  • All the various New Years
    • Jan 1 in Gregorian calendar is the most obvious
    • Check for large Lunar New Years too
• Follow the normal Google production freeze schedule

Launcher script

The main repo script serves as a standalone program and is often referred to as the "launcher script". This makes it easy to copy around and install as you don't have to install any other files from the git repo.

Whenever major changes are made to the launcher script, you should increment the VERSION variable in the launcher itself. At runtime, repo will check this to see if it needs to be updated (and notify the user automatically).

Key management

Every release has a git tag that is signed with a key that repo recognizes. Those keys are hardcoded inside of the repo launcher itself -- look for the KEYRING_VERSION and MAINTAINER_KEYS settings.

Adding new keys to the repo launcher will allow tags to be recognized by new keys, but only people using that updated version will be able to. Since the majority of users will be using an official launcher version, their version will simply ignore any new signed tags.

If you want to add new keys, it's best to register them long ahead of time, and then wait for that updated launcher to make its way out to everyone. Even then, there will be a long tail of users with outdated launchers, so be prepared for people asking questions.

Registering a new key

The process of actually adding a new key is quite simple.

1. Add the public half of the key to MAINTAINER_KEYS.
2. Increment KEYRING_VERSION so repo knows it needs to update.
3. Wait a long time after that version is in a release (~months) before trying to create a new release using those new keys.

Self update algorithm

When creating a new repo checkout with repo init, there are a few options that control how repo finds updates:

• --repo-url: This tells repo where to clone the full repo project itself. It defaults to the official project (REPO_URL in the launcher script).
• --repo-rev: This tells repo which branch to use for the full project. It defaults to the stable branch (REPO_REV in the launcher script).

Whenever repo sync is run, repo will, once every 24 hours, see if an update is available. It fetches the latest repo-rev from the repo-url. Then it verifies that the latest commit in the branch has a valid signed tag using git tag -v (which uses gpg). If the tag is valid, then repo will update its internal checkout to it.

If the latest commit doesn't have a signed tag, repo will fall back to the most recent tag it can find (via git describe). If that tag is valid, then repo will warn and use that commit instead.

If that tag cannot be verified, it gives up and forces the user to resolve.

If env variable REPO_SKIP_SELF_UPDATE is defined, this will bypass the self update algorithm.

Force an update

The repo selfupdate command can be used to force an immediate update. It is not subject to the 24 hour limitation.

Branch management

All development happens on the main branch and should generally be stable.

Since the repo launcher defaults to tracking the stable branch, it is not normally updated until a new release is available. If something goes wrong with a new release, an older release can be force pushed and clients will automatically downgrade.

The maint branch is used to track the previous major release of repo. It is not normally meant to be used by people as stable should be good enough. Once a new major release is pushed to the stable branch, then the previous major release can be pushed to maint. For example, when stable moves from v1.10.x to v1.11.x, then the maint branch will be updated from v1.9.x to v1.10.x.

We don't have parallel release branches/series. Typically all tags are made against the main branch and then pushed to the stable branch to make it available to the rest of the world. Since repo doesn't typically see a lot of changes, this tends to be OK.

Creating a new release

When you want to create a new release, you'll need to select a good version and create a signed tag using a key registered in repo itself. Typically we just tag the latest version of the main branch. The tag could be pushed now, but it won't be used by clients normally (since the default repo-rev setting is stable). This would allow some early testing on systems who explicitly select main.

Creating a signed tag

Lets assume your keys live in a dedicated directory, e.g. ~/.gnupg/repo/.

*** note If you need access to the official keys, check out the internal documentation at go/repo-release. Note that only official maintainers of repo will have access as it describes internal processes for accessing the restricted keys.

---

# Pick the new version.
$ t=v2.30

# Create a new signed tag with the current HEAD.
$ ./release/sign-tag.py $t

# Verify the signed tag.
$ git show $t

Push the new release

Once you're ready to make the release available to everyone, push it to the stable branch.

Make sure you never push the tag itself to the stable branch! Only push the commit -- note the use of ^0 below.

$ git push https://gerrit-review.googlesource.com/git-repo $t
$ git push https://gerrit-review.googlesource.com/git-repo $t^0:stable

If something goes horribly wrong, you can force push the previous version to the stable branch and people should automatically recover. Again, make sure you never push the tag itself!

$ oldrev="whatever-old-commit"
$ git push https://gerrit-review.googlesource.com/git-repo $oldrev:stable --force

Announce the release

Once you do push a new release to stable, make sure to announce it on the repo-discuss@googlegroups.com group. Here is an example announcement.

You can create a short changelog using the command:

# If you haven't pushed to the stable branch yet, you can use origin/stable.
# If you have pushed, change origin/stable to the previous release tag.
# This assumes "main" is the current tagged release.  If it's newer, change it
# to the current release tag too.
$ git log --format="%h (%aN) %s" --no-merges origin/stable..main

Project References

Here's a table showing the relationship of major tools, their EOL dates, and their status in Ubuntu & Debian. Those distros tend to be good indicators of how long we need to support things.

Things in bold indicate stuff to take note of, but does not guarantee that we still support them. Things in italics are things we used to care about but probably don't anymore.

Date	EOL	Git	Python	SSH	Ubuntu / Debian	Git	Python	SSH
Apr 2008				5.0
Jun 2008				5.1
Oct 2008	Oct 2013		2.6.0		10.04 Lucid - 10.10 Maverick / Squeeze
Dec 2008	Feb 2009		3.0.0
Feb 2009				5.2
Feb 2009	Mar 2012				Debian 5 Lenny	1.5.6.5	2.5.2
Jun 2009	Jun 2016		3.1.0		10.04 Lucid - 10.10 Maverick / Squeeze
Sep 2009				5.3	10.04 Lucid
Feb 2010	Oct 2012	1.7.0			10.04 Lucid - 12.04 Precise - 12.10 Quantal
Mar 2010				5.4
Apr 2010				5.5	10.10 Maverick
Apr 2010	Apr 2015				10.04 Lucid	1.7.0.4	2.6.5 3.1.2	5.3
Jul 2010	Dec 2019		2.7.0		11.04 Natty -
Aug 2010				5.6
Oct 2010					10.10 Maverick	1.7.1	2.6.6 3.1.3	5.5
Jan 2011				5.7
Feb 2011				5.8	11.04 Natty
Feb 2011	Feb 2016				Debian 6 Squeeze	1.7.2.5	2.6.6 3.1.3
Apr 2011					11.04 Natty	1.7.4	2.7.1 3.2.0	5.8
Sep 2011				5.9	12.04 Precise
Oct 2011	Feb 2016		3.2.0		11.04 Natty - 12.10 Quantal
Oct 2011					11.10 Ocelot	1.7.5.4	2.7.2 3.2.2	5.8
Apr 2012				6.0	12.10 Quantal
Apr 2012	Apr 2019				12.04 Precise	1.7.9.5	2.7.3 3.2.3	5.9
Aug 2012				6.1	13.04 Raring
Sep 2012	Sep 2017		3.3.0		13.04 Raring - 13.10 Saucy
Oct 2012	Dec 2014	1.8.0			13.04 Raring - 13.10 Saucy
Oct 2012					12.10 Quantal	1.7.10.4	2.7.3 3.2.3	6.0
Mar 2013				6.2	13.10 Saucy
Apr 2013					13.04 Raring	1.8.1.2	2.7.4 3.3.1	6.1
May 2013	May 2018				Debian 7 Wheezy	1.7.10.4	2.7.3 3.2.3
Sep 2013				6.3
Oct 2013					13.10 Saucy	1.8.3.2	2.7.5 3.3.2	6.2
Nov 2013				6.4
Jan 2014				6.5
Feb 2014	Dec 2014	1.9.0			14.04 Trusty
Mar 2014	Mar 2019		3.4.0		14.04 Trusty - 15.10 Wily / Jessie
Mar 2014				6.6	14.04 Trusty - 14.10 Utopic
Apr 2014	Apr 2024				14.04 Trusty	1.9.1	2.7.5 3.4.0	6.6
May 2014	Dec 2014	2.0.0
Aug 2014	Dec 2014	2.1.0			14.10 Utopic - 15.04 Vivid / Jessie
Oct 2014				6.7	15.04 Vivid
Oct 2014					14.10 Utopic	2.1.0	2.7.8 3.4.2	6.6
Nov 2014	Sep 2015	2.2.0
Feb 2015	Sep 2015	2.3.0
Mar 2015				6.8
Apr 2015	May 2017	2.4.0
Apr 2015	Jun 2020				Debian 8 Jessie	2.1.4	2.7.9 3.4.2
Apr 2015					15.04 Vivid	2.1.4	2.7.9 3.4.3	6.7
Jul 2015	May 2017	2.5.0			15.10 Wily
Jul 2015				6.9	15.10 Wily
Aug 2015				7.0
Aug 2015				7.1
Sep 2015	May 2017	2.6.0
Sep 2015	Sep 2020		3.5.0		16.04 Xenial - 17.04 Zesty / Stretch
Oct 2015					15.10 Wily	2.5.0	2.7.9 3.4.3	6.9
Jan 2016	Jul 2017	2.7.0			16.04 Xenial
Feb 2016				7.2	16.04 Xenial
Mar 2016	Jul 2017	2.8.0
Apr 2016	Apr 2026				16.04 Xenial	2.7.4	2.7.11 3.5.1	7.2
Jun 2016	Jul 2017	2.9.0			16.10 Yakkety
Jul 2016				7.3	16.10 Yakkety
Sep 2016	Sep 2017	2.10.0
Oct 2016					16.10 Yakkety	2.9.3	2.7.11 3.5.1	7.3
Nov 2016	Sep 2017	2.11.0			17.04 Zesty / Stretch
Dec 2016	Dec 2021		3.6.0		17.10 Artful - 18.04 Bionic - 18.10 Cosmic
Dec 2016				7.4	17.04 Zesty / Debian 9 Stretch
Feb 2017	Sep 2017	2.12.0
Mar 2017				7.5	17.10 Artful
Apr 2017					17.04 Zesty	2.11.0	2.7.13 3.5.3	7.4
May 2017	May 2018	2.13.0
Jun 2017	Jun 2022				Debian 9 Stretch	2.11.0	2.7.13 3.5.3	7.4
Aug 2017	Dec 2019	2.14.0			17.10 Artful
Oct 2017	Dec 2019	2.15.0
Oct 2017				7.6	18.04 Bionic
Oct 2017					17.10 Artful	2.14.1	2.7.14 3.6.3	7.5
Jan 2018	Dec 2019	2.16.0
Apr 2018	Mar 2021	2.17.0			18.04 Bionic
Apr 2018				7.7	18.10 Cosmic
Apr 2018	Apr 2028				18.04 Bionic	2.17.0	2.7.15 3.6.5	7.6
Jun 2018	Mar 2021	2.18.0
Jun 2018	Jun 2023		3.7.0		19.04 Disco - Buster
Aug 2018				7.8
Sep 2018	Mar 2021	2.19.0			18.10 Cosmic
Oct 2018				7.9	19.04 Disco / Buster
Oct 2018					18.10 Cosmic	2.19.1	2.7.15 3.6.6	7.7
Dec 2018	Mar 2021	2.20.0			19.04 Disco - 19.10 Eoan / Buster
Feb 2019	Mar 2021	2.21.0
Apr 2019				8.0	19.10 Eoan
Apr 2019					19.04 Disco	2.20.1	2.7.16 3.7.3	7.9
Jun 2019		2.22.0
Jul 2019	Jul 2024				Debian 10 Buster	2.20.1	2.7.16 3.7.3	7.9
Aug 2019	Mar 2021	2.23.0
Oct 2019	Oct 2024		3.8.0		20.04 Focal - 20.10 Groovy
Oct 2019				8.1
Oct 2019					19.10 Eoan	2.20.1	2.7.17 3.7.5	8.0
Nov 2019	Mar 2021	2.24.0
Jan 2020	Mar 2021	2.25.0			20.04 Focal
Feb 2020				8.2	20.04 Focal
Mar 2020	Mar 2021	2.26.0
Apr 2020	Apr 2030				20.04 Focal	2.25.1	2.7.17 3.8.2	8.2
May 2020	Mar 2021	2.27.0			20.10 Groovy
May 2020				8.3
Jul 2020	Mar 2021	2.28.0
Sep 2020				8.4	21.04 Hirsute / Bullseye
Oct 2020	Mar 2021	2.29.0
Oct 2020					20.10 Groovy	2.27.0	2.7.18 3.8.6	8.3
Oct 2020	Oct 2025		3.9.0		21.04 Hirsute / Bullseye
Dec 2020	Mar 2021	2.30.0			21.04 Hirsute / Bullseye
Mar 2021		2.31.0		8.5
Apr 2021				8.6
Apr 2021	Jan 2022				21.04 Hirsute	2.30.2	2.7.18 3.9.4	8.4
Jun 2021		2.32.0
Aug 2021		2.33.0		8.7
Aug 2021	Aug 2026				Debian 11 Bullseye	2.30.2	2.7.18 3.9.2	8.4
Sep 2021				8.8
Oct 2021		2.34.0	3.10.0		22.04 Jammy
Jan 2022		2.35.0
Feb 2022				8.9	22.04 Jammy
Apr 2022		2.36.0		9.0
Apr 2022	Apr 2032				22.04 Jammy	2.34.1	2.7.18 3.10.6	8.9
Jun 2022		2.37.0
Oct 2022		2.38.0		9.1
Oct 2022			3.11.0		Bookworm
Dec 2022		2.39.0			Bookworm
Feb 2023				9.2	Bookworm
Mar 2023		2.40.0		9.3
Jun 2023		2.41.0
Jun 2023	Jun 2028				Debian 12 Bookworm	2.39.2	3.11.2	9.2
Aug 2023		2.42.0		9.4
Oct 2023			3.12.0	9.5
Nov 2022		2.43.0
Dec 2023				9.6
Feb 2024		2.44.0
Mar 2024				9.7
Oct 2024			3.13.0
Date	EOL	Git	Python	SSH	Ubuntu / Debian	Git	Python	SSH