1863519 - (hg-to-git) [meta] Migrate from Mercurial to Git for Firefox Development

Status: NEW

(Developer Infrastructure :: General, task)

Description

[:glob ✱]

FIREFOX DEVELOPMENT IS MOVING FROM MERCURIAL TO GIT

For a long time Firefox Desktop development has supported both Mercurial and
Git users. This dual SCM requirement places a significant burden on teams which
are already stretched thin in parts. We have made the decision to move Firefox
development to Git.

• We will continue to use Bugzilla, moz-phab, Phabricator, and Lando
• Although we'll be hosting the repository on GitHub, our contribution workflow
  will remain unchanged and we will not be accepting Pull Requests at this time
• We're still working through the planning stages, but we're expecting at least
  six months before the migration begins

APPROACH

In order to deliver gains into the hands of our engineers as early as possible,
the work will be split into two components: developer-facing first, followed by
piecemeal migration of backend infrastructure.

Phase One - Developer Facing

We'll switch the primary repository from Mercurial to Git, at the same time
removing support for Mercurial on developers' workstations. At this point
you'll need to use Git locally, and will continue to use moz-phab to submit
patches for review.

All changes will land on the Git repository, which will be unidirectionally
synchronised into our existing Mercurial infrastructure.

Phase Two - Infrastructure

Respective teams will work on migrating infrastructure that sits atop
Mercurial to Git. This will happen in an incremental manner rather than
all at once.

By the end of this phase we will have completely removed support of
Mercurial from our infrastructure.