Mozilla Firefox: Development Specifics

Status: Draft

Overview

This document discusses specifics related to Mozilla's newly proposed Firefox development model.

Please note this is a draft document and subject to change.

Discussion should take place on dev-planning and changes should be submitted as pull requests on GitHub.

Main Repositories

The general naming scheme should work equally well for other products if they decide to follow the same development/channel/repo model. Also note if in the future Firefox releases split from platform releases the naming scheme does not need to change...we would merely create firefox-* repositories.

mozilla-central was chosen as the main development repository name due to familiarity, to prevent developers from having to alter their local repos, and to prevent needless changes to tools.

Development vs Release

The repositories can generally be grouped into two overall processes: development and release. Project repositories and mozilla-central are part of the development process. The downstream repositories are part of the release process.

This document mainly covers the release process. Details about project pages, feature tracking, and bug management are out of scope for this proposal and will be discussed soon.

Update Channels

What Happens Where?

Versioning

Because updates are (intended) to be silent and automatic we can generally assume a user on a given channel is on the latest available build. This assumption simplifies things greatly.

Firefox Versioning

Unless major issues are discovered with the scheme, this is how builds in the assorted repositories will identify themselves:

The following considerations are reflected in the versioning scheme:

We aren't using "a" and "b" as it would be confusing as it relates to aurora and beta.

Gecko versioning

Gecko versioning will tie into Firefox versioning regardless of the Firefox version scheme above. For Firefox 5, the gecko version will be 5.0, for Firefox 6, 6.0, etc.

Please note that binary extensions will already need to be recompiled for Firefox 5.

Project Repositories

Project repositories are cheap and developers should not hesitate to ask for one.

Project repositories should be grouped by team or area in subdirectories under hg.mozilla.org/projects. In this scheme Tracemonkey can be found at hg.mozilla.org/projects/js/tracemonkey. Additional repos for the js team would be created in hg.mozilla.org/projects/js as well. This should keep hg.mozilla.org organized and enable automated tools to enumerate the available project repositories easily.

Please note the above naming convention is different from what was used in the past. Existing project repositories may need to be moved around to fit in with the new scheme.

Project repositories automatically get an update channel when nightly builds are enabled. The naming convention for the channel is the path from root repo, with slashes converted to dashes. For the Tracemonkey example above, builds would be generated and posted to projects-js-tracemonkey.

Developers may also wish to check out one of the already existing disposable project repositories.

These naming conventions for project repositories have not been widely discussed yet. Please give feedback.

The Shadow Repository

Having a restricted shadow repository is new to Mozilla. We are trying to balance the fact we are open source with the need to secure our users by not publishing information about security vulnerabilities before our users are protected.

Most developers and users need not worry or care about mozilla-shadow, so feel free to ignore it (most of the graphics omit it for clarity).

mozilla-shadow

shadow channel

Current Users 0
Anticipated Users ~10
Type of User The security team and QA
Anticipated Update Rate nightly
Branded Not branded as Firefox

Localization

Localization work will be split into similar repositories:

There will be 8 or so locales that track mozilla-central, localizing alongside en-US development. Other locales can track mozilla-central if they would like to as well but they won't be asked to explicitly.

TBD: Which specific 8 or so locales are best to follow mozilla-central? This seems to be a combination of locales comfortable localizing before string freeze, and also locales that are useful to developers, like right-to-left for example.

mozilla-central will be string frozen for en-US at the mozilla-central → mozilla-aurora merge point. No en-US string changes will be allowed on mozilla-aurora. The mozilla-central → mozilla-aurora merge date will happen on schedule so the string freeze should not come as a surprise.

For locales that don't track mozilla-central, their work is done in l10n-aurora, which tracks mozilla-aurora. This means most locales have 6 weeks to complete their localizations.

Schedule of Important Milestones

In general, each stage of the process (and activity pertaining to a particular version) lasts for 6 weeks.

Firefox 5

Firefox 5 will be slightly different from future releases due to the development overlap (or lack thereof) with Firefox 4:

Rather than 6 weeks for mozilla-central, mozilla-aurora, and mozilla-beta we instead have 3 weeks for development on mozilla-central, 5 weeks to converge and stabilize on mozilla-aurora, and 5 weeks to validate on mozilla-beta.

Firefox 6

Firefox 6 will start the normal schedule where every step in the cycle takes 6 weeks. Firefox 6's development cycle starts when Firefox 5 is cloned from mozilla-central to mozilla-aurora (on 2011-04-12).

Please do note that chemspills / rapid response updates are not reflected in these schedules and will be dealt with on an as-needed basis.

Cloning Mechanics

The following describes the mozilla-central to mozilla-aurora mechanics. mozilla-aurora to mozilla-beta mechanics follow the same steps, with the exception of tagging (use BETA_BASE_YYYYMMDD), and versioning (strip off the a2 suffix).

  1. Never delete the aurora repo, we need the history.
  2. Tag mozilla-central with AURORA_BASE_YYYYMMDD. 
                hg tag -R mozilla-central AURORA_BASE_`date +%Y%m%d`
            hg out
            # review
            hg push
  3. Tag and close old head on aurora. 
                hg tag -R mozilla-aurora FIREFOX_AURORA_VERSION
            hg commit -R mozilla-aurora -r default --close-branch -m 'closing old head'
  4. Push from m-c to a new head on aurora. 
                hg pull -u -R mozilla-aurora -r AURORA_BASE_`date +%Y%m%d` http://hg.mozilla.org/mozilla-central
  5. Update to the latest aurora 
                cd mozilla-aurora
            hg update -C
  6. Bump xpcom version (only for the mozilla-central merge, see bug 653731) 
                (manually edit xpcom/components/Module.h)
  7. Bump aurora version. 
                sed -i -e 's/a1/a2/g' browser/config/version.txt js/src/config/milestone.txt config/milestone.txt
            (for beta 's/a1/a2/g' is 's/a2//g')
            (manually edit mobile/confvars.sh to bump the version)
            hg commit -m 'Version bump'
  8. Bump mozilla-central version. (manually edit mobile/confvars.sh to bump the version) (skip this step for mozilla-aurora → mozilla-beta)
  9. Set aurora branding in browser/confvars.sh (MOZ_BRANDING_DIRECTORY=browser/branding/aurora)
  10. Human needs to review list of changes since the last AURORA_BASE_YYYYMMDD tag, and figure out which changes to bring forward, and which changes to throw away.
  11. Use "hg transplant" to take the changes we want to bring forward and bring over to the new head. Make note of the related bugs, and comment in them to notify the relevant stakeholders that they've been transplanted to mozilla-aurora.
  12. Human needs to resolve any merge conflicts.
    Note: some specific files need careful human review of any changes, even if there are no merge conflicts. all.js, firefox.js, configure.in, mozconfig
  13. Use clobberer to clobber all builds on mozilla-aurora. This should be done immediately before the following step (so there are no other pushes in between).
  14. Human needs to "hg push -f" back to mozilla-aurora

Rapid Release / Chemspill Updates

We are still in the information gathering phase and will have this section filled out in the next couple of days.

General Observations

Deferring work

No work is deferred from upstream repos to downstream repos. If your feature / change isn't finished on mozilla-central, mozilla-aurora is not the place to fix it up. If there is outstanding work on mozilla-aurora do not plan to fix it in mozilla-beta. The clone / pull dates are published far in advance so there should be ample time to plan. If it's not ready it should be backed out or preffed off. There will be another release in 6-12 weeks for the fix to try to make it in again.

Time-based cloning

Cloning between repos will happen on schedule. Again, consistency is key. Groups will be able to plan and won't need to be intimately involved with the release process to know where fixes are and where fixes should be landed.

The merge between release repos should be automatic

When the time comes to merge upstream release repositories with downstream repositories we are essentially replacing the downstream repository with a copy of the upstream. Because the merge/clone should never fail and it happens on a set schedule it will likely be automated.

Please note in the section above there is still discussion on what can be automated and the proper version control mechanics.

Preffing off / backing out happens after the clone

When cloning from mozilla-central to mozilla-aurora the backouts and pref offs take place on the mozilla-aurora repo. This allows mozilla-central to use the complete allotted time for development and utilizes mozilla-aurora's time for convergence.