mr mr cote

Educational, Investigative, and Absurd Writings by M. R. Côté

Decisions, Decisions, Decisions: Driving Change at Mozilla

| Comments

As the manager responsible for driving the decision and process behind the move to Phabricator at Mozilla, I’ve been asked to write about my recent experiences, including how this decision was implemented, what worked well, and what I might have done differently. I also have a few thoughts about decision making both generally and at Mozilla specifically.

Please note that these thoughts reflect only my personal opinions. They are not a pronouncement of how decision making is or will be done at Mozilla, although I hope that my account and ideas will be useful as we continue to define and shape processes, many of which are still raw years after we became an organization with more than a thousand employees, not to mention the vast number of volunteers.


Mozilla has used Bugzilla as both an issue tracker and a code-review tool since its inception almost twenty years ago. Bugzilla was arguably the first freely available web-powered issue tracker, but since then, many new apps in that space have appeared, both free/open-source and proprietary. A few years ago, Mozilla experimented with a new code-review solution, named (boringly) “MozReview”, which was built around Review Board, a third-party application. However, Mozilla never fully adopted MozReview, leading to code review being split between two tools, which is a confusing situation for both seasoned and new contributors alike.

There were many reasons that MozReview didn’t completely catch on, some of which I’ve mentioned in previous blog and newsgroup posts. One major factor was the absence of a concrete, well-communicated, and, dare I say, enforced decision. The project was started by a small number of people, without a clearly defined scope, no consultations, no real dedicated resources, and no backing from upper management and leadership. In short, it was a recipe for failure, particularly considering how difficult change is even in a perfect world.

Having recognized this failure last year, and with the urging of some people at the director level and above, my team and I embarked on a process to replace both MozReview and the code-review functionality in Bugzilla with a single tool and process. Our scope was made clear: we wanted the tool that offered the best mechanics for code-review at Mozilla specifically. Other bits of automation, such as “push-to-review” support and automatic landings, while providing many benefits, were to be considered separately. This division of concerns helped us focus our efforts and make decisions clearer.

Our first step in the process was to hold a consultation. We deliberately involved only a small number of senior engineers and engineering directors. Past proposals for change have faltered on wide public consultation: by their very nature, you will get virtually every opinion imaginable on how a tool or process should be implemented, which often leads to arguments that are rarely settled, and even when “won” are still dominated by the loudest voices—indeed, the quieter voices rarely even participate for fear of being shouted down. Whereas some more proactive moderation may help, using a representative sample of engineers and managers results in a more civil, focussed, and productive discussion.

I would, however, change one aspect of this process: the people involved in the consultation should be more clearly defined, and not an ad-hoc group. Ideally we would have various advisory groups that would provide input on engineering processes. Without such people clearly identified, there will always be lingering questions as to the authority of the decision makers. There is, however, still much value in also having a public consultation, which I’ll get to shortly.

There is another aspect of this consultation process which was not clearly considered early on: what is the honest range of solutions we are considering? There has been a movement across Mozilla, which I fully support, to maximize the impact of our work. For my team, and many others, this means a careful tradeoff of custom, in-house development and third-party applications. We can use entirely custom solutions, we can integrate a few external apps with custom infrastructure, or we can use a full third-party suite. Due to the size and complexity of Firefox engineering, the latter is effectively impossible (also the topic for a series of posts). Due to the size of engineering-tools groups at Mozilla, the first is often ineffective.

Thus, we really already knew that code-review was a very likely candidate for a third-party solution, integrated into our existing processes and tools. Some thorough research into existing solutions would have further tightened the project’s scope, especially given Mozilla’s particular requirements, such as Mercurial support, which are in part due to a combination of scale and history. In the end, there are few realistic solutions. One is Review Board, which we used in MozReview. Admittedly we introduced confusion into the app by tying it too closely to some process-automation concepts, but it also had some design choices that were too much of a departure from traditional Firefox engineering processes.

The other obvious choice was Phabricator. We had considered it some years ago, in fact as part of the MozReview project. MozReview was developed as a monolithic solution with a review tool at its core, so the fact that Phabricator is written in PHP, a language without much presence at Mozilla today, was seen as a pretty big problem. Our new approach, though, in which the code-review tool is seen as just one component of a pipeline, means that we limit customizations largely to integration with the rest of the system. Thus the choice of technology is much less important.

The fact that Phabricator was virtually a default choice should have been more clearly communicated both during the consultation process and in the early announcements. Regardless, we believe it is in fact a very solid choice, and that our efforts are truly best spent solving the problems unique to Mozilla, of which code review is not.

To sum up, small-scale consultations are more effective than open brainstorming, but it’s important to really pay attention to scope and constraints to make the process as effective and empowering as possible.


Lest the above seem otherwise, open consultation does provide an important part of the process, not in conceiving the initial solution but in vetting it. The decision makers cannot be “the community”, at least, not without a very clear process. It certainly can’t be the result of a discussion on a newsgroup. More on this later.

Identifying the decision maker is a problem that Mozilla has been wrestling with for years. Mitchell has previously pointed out that we have a dual system of authority: the module system and a management hierarchy. Decisions around tooling are even less clear, given that the relevant modules are either nonexistent or sweepingly defined. Thus in the absence of other options, it seemed that this should be a decision made by upper management, ultimately the Senior Director of Engineering Operations, Laura Thomson. My role was to define the scope of the change and drive it forward.

Of course since this decision affects every developer working on Firefox, we needed the support of Firefox engineering management. This has been another issue at Mozilla; the directorship was often concerned with the technical aspects of the Firefox product, but there was little input from them on the direction of the many supporting areas, including build, version control, and tooling. Happily I found out that this problem has been rectified. The current directors were more than happy to engage with Laura and me, backing our decision as well as providing some insights into how we could most effectively communicate it.

One suggestion they had was to set up a small hosted test instance and give accounts to a handful of senior engineers. The purpose of this was to both give them a heads up before the general announcement and to determine if there were any major problems with the tool that we might have missed. We got a bit of feedback, but nothing we weren’t already generally aware of.

At this point we were ready for our announcement. It’s worth pointing out again that this decision had effectively already been made, barring any major issues. That might seem disingenuous to some, but it’s worth reiterating two major points: (a) a decision like this, really, any nontrivial decision, can’t be effectively made by a large group of people, and (b) we did have to be honestly open to the idea that we might have missed some big ramification of this decision and be prepared to rethink parts, or maybe even all, of the plan.

This last piece is worth a bit more discussion. Our preparation for the general announcement included several things: a clear understanding of why we believe this change to be necessary and desirable, a list of concerns we anticipated but did not believe were blockers, and a list of areas that we were less clear on that could use some more input. By sorting out our thoughts in this way, we could stay on message. We were able to address the anticipated concerns but not get drawn into a long discussion. Again this can seem dismissive, but if nothing new is brought into the discussion, then there is no benefit to debating it. It is of course important to show that we understand such concerns, but it is equally important to demonstrate that we have considered them and do not see them as critical problems. However, we must also admit when we do not yet have a concrete answer to a problem, along with why we don’t think it needs an answer at this point—for example, how we will archive past reviews performed in MozReview. We were open to input on this issues, but also did not want to get sidetracked at this time.

All of this was greatly aided by having some members of Firefox and Mozilla leadership provide input into the exact wording of the announcement. I was also lucky to have lots of great input from Mardi Douglass, this area (internal communications) being her specialty. Although no amount of wordsmithing will ensure a smooth process, the end result was a much clearer explanation of the problem and the reasons behind our specific solution.

Indeed, there were some negative reactions to this announcement, although I have to admit that they were fewer than I had feared there would be. We endeavoured to keep the discussion focussed, employing the above approach. There were a few objections we hadn’t fully considered, and we publicly admitted so and tweaked our plans accordingly. None of the issues raised were deemed to be show-stoppers.

There were also a very small number of messages that crossed a line of civility. This line is difficult to determine, although we have often been too lenient in the past, alienating employees and volunteers alike. We drew the line in this discussion at posts that were disrespectful, in particular those that brought little of value while questioning our motives, abilities, and/or intentions. Mozilla has been getting better at policing discussions for toxic behaviour, and I was glad to see a couple people, notably Mike Hoye, step in when things took a turn for the worse.

There is also a point in which a conversation can start to go in circles, and in the discussion around Phabricator (in fact in response to a progress update a few months after the initial announcement) this ended up being around the authority of the decision makers, that is, Laura and myself. At this point I requested that a Firefox engineering director, in this case Joe Hildebrand, get involved and explain his perspective and voice his support for the project. I wish I didn’t have to, but I did feel it was necessary to establish a certain amount of credibility by showing that Firefox leadership was both involved with and behind this decision.

Although disheartening, it is also not surprising that the issue of authority came up, since as I mentioned above, decision making has been a very nebulous topic at Mozilla. There is a tendency to invoke terms like “open” and “transparent” without in any way defining them, evoking an expectation that everyone shares an understanding of how we ought to make decisions, or even how we used to make decisions in some long-ago time in Mozilla’s history. I strongly believe we need to lay out a decision-making framework that values openness and transparency but also sets clear expectations of how these concepts fit into the overall process. The most egregious argument along these lines that I’ve heard is that we are a “consensus-based organization”. Even if consensus were possible in a decision that affects literally hundreds, if not thousands, of people, we are demonstrably not consensus-driven by having both module and management systems. We do ourselves a disservice by invoking consensus when trying to drive change at Mozilla.

On a final note, I thought it was quite interesting that the topic of decision making, in the sense of product design, came up in the recent CNET article on Firefox 57. To quote Chris Beard, “If you try to make everyone happy, you’re not making anyone happy. Large organizations with hundreds of millions of users get defensive and try to keep everybody happy. Ultimately you end up with a mediocre product and experience.” I would in fact extend that to trying to make all Mozillians happy with our internal tools and processes. It’s a scary responsibility to drive innovative change at Mozilla, to see where we could have a greater impact and to know that there will be resistance, but if Mozilla can do it in its consumer products, we have no excuse for not also doing so internally.

Comments