On pair programming

In my past and current projects, there was always a hurdle in sharing knowledge effectively. Even if there is the best documentation for a project and each story is very well defined, including clear acceptance criteria, there is still a significant amount of knowledge hiding in shadows.

Shadow knowledge that is never documented and passed around only by “tribe” stories. No matter how hard you try to clarify the reasoning behind the given feature, model, UI component, there is always this small detail that you unconsciously omit – not purposely, of course. Most of the time, it is either something so evident to you that you assume everyone knows it.

That shadow knowledge is everywhere, especially in long-lasting legacy projects. It prevents to build a shared understanding not only among teams but also within an organization. The same applies to new joiners. The only difference, in that case, is the gap in knowledge that needs to be fulfilled, and this is rarely done thoroughly by asking people to read documentation and code itself. Too many times, documentation is outdated, and reading code is like reading a snapshot of the current system without getting any historical data to back up its current state.

The solution that I've tried many times and seems to be working best for me and my peers is pair programming (and in more extreme scenarios: mob programming but this is an exciting topic of its own and deserves a separate blog post).

There are different approaches to how pair programming sessions should be performed. Still, one thing that does not change is the purpose of it—sharing the knowledge that is not easily shareable in the official documentation. Rarely it is being written down that a feature was implemented the way it was because of low headcount and time pressure. Pair programming sessions give two people a safe boundary where they can, not only code a solution together but also build trust and share uncomfortable facts about the existing solutions.

I try to keep in mind a few simple rules when doing pair programming that makes them practical for me and my colleagues (at least they never said otherwise :)).

Keep them remote

I work remotely for about eight years now, so “remote” is a natural environment for me. Still, even when I was working in the office, I encouraged my peers to do pair programming sessions remotely. The main benefit is that each peer can work from their computer and use their environment, editor settings, etc. This approach removes the problem of using the same settings everywhere, which always comes in the way of effectiveness. It is straightforward nowadays to share code via, e.g., git branch, and get the same code state in a second if we switch roles. Another significant benefit is that both peers are kept “in the zone” by staying in a phone booth space or at least by using headphones (especially when those are with active noise cancellation). Pairing in person was always too vulnerable to all office-related interruptions.

Do not assume anything

An assumption is an enemy of understanding and finding common ground. Whenever I pair program with someone senior, someone who works in the same problem domain or even someone who is considered an expert where I'm not, I try to pretend I'm pairing with someone who is junior and lacks domain knowledge. If we both use the same tactic, it is easy to build up trust and being more comfortable to share all legacy specific details about the code we are working with. I'm also sure I do not forget to share any insights that, for me, seem to be obvious.

Do not tell how

This rule is crucial for a successful pair programming. I never say what my peer has to type in or how to approach a problem. Quite the opposite, I try to give as much historical background and context on the current code so that the other side can propose a solution on their own. This way, I can challenge my peer to come up with a solution that I might never have to think about. When they are going in the wrong direction (e.g., I've been there already and tried that), I'm not cutting conversation there. I'm allowing them to try it and fail, this way we can be on the same page and understand the limitations and possibilities of the current code much better.

Last but not least, there is also a social aspect of pair programming. After all, what is the more delightful way to better know your colleagues then sharing with them your passion for programming and doing this together at the same time?