Moving Away From CVS: A Vote

David Miller justdave at
Sat Sep 5 21:23:17 UTC 2009

I also personally prefer Bzr over Hg.  We're using it already for bmo's
local hacks, and to me the command set just seems more friendly than Hg.
 The scalability/performance issues that Mozilla ran into don't really
affect us because our codebase isn't as huge as theirs.

If we end up going with this, I'll see to it that we get "real" support
for it on Mozilla's infrastructure (rather than the "nothing more than a
bare repo" that we have for bmo currently, that shares a server with one
of the staging boxes).

Max Kanat-Alexander wrote on 9/4/09 6:28 PM:
>     Okay, we've had this discussion before, but this time, we have to
> actually do it. We've been on CVS for too long--we may be the only
> remaining major Mozilla project still using CVS for primary development.
> We're certainly the only major open source project that I know of and
> interact with regularly that still uses CVS.
>     The only reason that we haven't moved yet is that we have a conflict:
>     * Bzr is known by the Bugzilla developers and is technically
> superior to Hg in almost every way except scalability (and even that may
> be fixed as of bzr 1.16).
>     * Hg is supported by the Mozilla Corporation, has an extensive
> infrastructure at Mozilla, and is already in use by Mozilla localizers.
>     If you doubt that bzr is technically superior, here are a few points:
>     * Compare the standard web interface to Hg (hgweb:
> ) to the standard web interface for bzr
> (loggerhead: ).
>     * bzr has a *major* release nearly every month. (See the release
> notes: )
> Mercurial's major releases are roughly 3 to 4 months apart (and there
> were 9 months from 1.0 to 1.1).
>     * bzr tracks directory renames as well as file renames, meaning that
> it doesn't show hundreds of files being renamed if you rename a
> directory--it only shows the directory name changing. (This also means
> that bzr can show the existence of empty directories in its changeset
> history, and Mercurial cannot.)
>     * The commands used in bzr for a CVS-like workflow are *identical*
> to the commands used in CVS, drastically lessening the learning curve
> for users migrating from CVS.
>     However, Hg is supported by the Mozilla Corporation and they already
> have extensive infrastructure around it. Also, as Cedric has pointed out
> in the past, localizers are already using Hg.
>     To resolve the conflict, I am ***TAKING A VOTE***:
>     * Respond to this email either publicly (if you want to make an
> argument) or privately with your preference stated AT THE VERY TOP OF
> THE EMAIL. Anybody who is currently contributing to the Bugzilla Project
> or interacting with our CVS is eligible to vote. (If you are not a
> current contributor, please state your interest when voting.)
>     I will count all public and private votes, and we will move to
> whichever VCS receives a simple majority (51%) of the received votes.
> HOWEVER, if there is a clear consensus (75% or greater) among the
> reviewers (and a significant number of reviewers vote--more than just 3
> or 4), then there is a possibility we will just go with the reviewer
> consensus, though the non-reviewer votes will also be taken into account.
>     If you have any questions about the voting or about either VCS, feel
> free to respond here publicly and I'd be happy to clarify.
>     -Max

Dave Miller                         
System Administrator, Mozilla Corporation
Project Leader, Bugzilla Bug Tracking System

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