Patterns For Collective Code Ownership

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Reading time ~7 minutes

Following the somewhat schizophrenic challenges of dealing with person issues on collective code ownership, here we focus on the practices and practical aspects. How do we technically achieve collective ownership within teams?

We’re using the “simple pattern” approach again. For each pattern we have a suitable “anchor name”, a brief description and nothing more. This should be plenty to get moving  but feel free to expand on these and provide feedback.

Here’s the basic set of patterns to consider:

Code Caretaker

Let’s make it a bit less personal, encourage the team to understand what the caretaker role for code entails. It’s not a single person’s code – in fact the company paid us to write it for them. Code does still need occasional care and feeding – Enter the “Caretaker”.  Be wary though that caretakers may become owners.

Apprenticeship

Have your expert spend time teaching & explaining. An apprentice learns by doing – the old-fashioned way under the tutelage of a master craftsman guiding them full-time. This is time and effort-intensive for the pair involved but (unless you have a personality or performance problem) is a sure-fire way to get the knowledge shared.

If you need to expand to multiple team members in parallel,  skip forward to feature lead & tour of duty.

Ping-Pong Pairing

Try pair programming with an expert and novice together. Develop tests, then code, swap places. One person writes tests, the other codes. Depending on the confidence of the learner, they may focus more on writing the tests and understanding the code rather than coding solutions. Unequal pairing is quite tricky so monitor this carefully, your expert will need support in how to share, teach & coach.

Bug Squishing

Best with large backlogs of low-severity defects to start with. Cluster them into functional areas. Set a time-box to “learn by fixing” – delivery is not measured on volume fixed but by level of understanding (demonstrated by a high first-time pass rate on peer reviews). If someone needs help they learn to ask (or try, then ask) rather than hand over half-cut. This approach works with individuals having peer review support and successfully scales to multiple individuals operating on different areas in parallel.

A Third Pair of Eyes (Secondary Peer Review)

With either an “initiate” (new learner) or an experienced developer working on the coding, have both a learner and an expert participate in peer reviews on changes coming through – to learn and provide a safety net respectively. The newer developer should be encouraged to provide input and ask questions but has another expert as “backstop” for anything they might miss.

Sightseeing / Guided Tour

Run a guided walk-through for the team – typically a short round-table session. Tours are either led by the current SME (subject matter expert) or by a new learner (initiate). In the case of a new learner, the SME may wish to review their understanding first before encouraging them to lead a walk-through themselves.

Often an expert may fail to identify and share pieces of important but implicit information (tacit knowledge) whilst someone new to the code may spot these and emphasize different items or ask questions that an expert would not. Consider having your initiate lead a session with the expert as a backstop.

Feature Leads

The feature lead approach is one of my favourites. I’ve successfully acted as a feature lead on many areas with teams of all levels of experience where I needed to ramp up a large group on a functional area together.

By introducing a larger team, your expert will not have the capacity to remain hands-on and support the team at the same time. They must lead the team in a hands-off approach by providing review and subject/domain expertise only. This also addresses the single point of failure to “new” single point of failure risk seen with “apprenticeship”.

This is also a potential approach when an expert or prior owner steps in too frequently to undo or overwrite rather than coach other members activities. By ensuring they don’t have the bandwidth to get too involved you may be able to encourage some backing-off but use this approach with care in these situations to avoid personal flare-ups.

Cold Turkey

For extreme cases where “you can’t possibly survive” without a single point of failure, try cold turkey. Force yourself to work without them.

I read an article some years ago, (unfortunately I can’t track it down now) where the author explained how when he joined a project as manager, the leaders told him he must have “Dave” on the project as nobody else knew what Dave did. He spent a week of sleepless nights trying to figure out how to get Dave off the project. After removing Dave from the project, the team were forced to learn the bottleneck area themselves and delivered successfully.

(Apologies to any “Dave”s I know – this isn’t about any of you)

Business Rule Extraction

Get your initiate to study the code and write a short document, wiki article or blog defining the business rules in the order or hierarchy they’re hit. This is usually reserved for absolute new starters to learn the basics of an area and show they’ve understood it without damaging anything. It is however also a good precursor to a test retrofit.

Test Retrofit

A step up from business rule extraction whilst delivering some real value to the team. Encourage your learner to write a series of small functional tests for a specific functional area by prodding it, working out how to talk to it, what it does and what we believe it should do. Save the passing tests and get the results checked, peer reviewed and approved.

Chances are you might find some bugs too – decide whether to fix them now or later depending on your safety margin with your initiate.

Debt Payment

After a successful test retrofit, you can start refactoring and unit testing. As refactoring is not without risk this is generally an approach for a more experienced developer but offers a sound way of prizing out functionality and learning key areas in small parts.

This is also a natural point to start fixing any bugs found during a test retrofit.

National Service (also known as Jury Duty)

Have a couple of staff on short rotation (2-4 weeks) covering support & maintenance even on areas they don’t know. This is generally reserved for experienced team members who can assimilate new areas quickly but a great “leveller” in cross-training your team in hot areas.

Risks are generally around decision-making, customer responsiveness, turnaround time and overall lowering of performance but these are all short-term. I’ve often used this approach on mature teams to cross-train into small knowledge gaps or newly acquired legacy functional areas.

My preferred approach is to stagger allocation so that you have one member on “primary” support whilst another provides “backup” each sprint. For the member that covered primary in sprint one, they’re on backup in sprint 2. (expand this to meet your required capacity).

3-6 months of a national service approach should be enough to cover the most critical functional gaps on your team based on customer/user demand

Tour of Duty

Have your staff work on longer term rotations (1-6 months) working on a functional area or feature as part of a feature team. This couples up with the “feature lead” approach.

Again, this is an approach that is very useful for mature agile teams that understand and support working as feature teams but can be introduced on less-experienced teams without too much pain.

The tour of duty can also work beyond an individual role. For example a developer taking a 3-6 month rotation through support or testing will provide greater empathy and understanding of tester and user needs than simply rotating through feature delivery. (My time spent providing customer support permanently changed my attitude toward cosmetic defects as a developer)

Adjacency

This takes a lot more planning and management than the other approaches described but is the most comprehensive.

From the areas each team member knows; identify where functional or technical adjacent areas lay and then use a subset of the approaches described here to build up skills in that adjacency.

Develop a knowledge growth plan for every team member sharing and leveraging their growth across areas with each other. Although this is an increase in coordination and planning, the value here is that your teams get to see the big picture on their growth and have clear direction.

All these patterns have a selection of merits and pitfalls. some won’t work in your situation and some may be more successful than others. There are undoubtedly more that could be applied.

Starting in your next sprint, try some of what’s provided here to developing shared ownership and knowledge transfer for your teams. Pick one or more patterns, figure out the impacts and give them a try.

(Coming soon “Building a Case for Collective Code Ownership” – when solving the technical side isn’t enough)

Escaping the Oubliette (Part 1a) – Debt Prevention

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Reading time ~3 minutes

This is a partial re-post of Escaping the Oubliette (Part 1). I’ve split the article into smaller readable components.

Great, I’ve got my incoming defect strategy nailed,

Now how do I prevent defects and debt in new code?

In 5 words…

Continuous attention to technical excellence.

Here’s my top 7 (there are plenty more)

  1. Acceptance Criteria – Be really disciplined on your acceptance criteria & acceptance tests, team up with Analysts, Testers, Product Owners if you have them and attack your stories from every angle. A good approach to this is a “story kick-off” where the whole team dismantles a story before starting.
  2. Thinking Time – don’t just start coding right away, task things out, try the 10 minute test plan, discuss your approach with your peers and for more complex or large items, try the “just enough design” approach.
  3. TDD – It’s hard to start but has an immense impact.  I’ve just seen a team complete their first project using TDD. 3 weeks into their final round of post feature-complete testing, their defect run-rate hasn’t had the testing spike seen on prior projects. In fact they’re keeping on top of all new incoming defects and have time to start paying down the historic backlog.
  4. Pair Programming – Do it in half-day trial chunks if you don’t have the stomach for going full-tilt. I’ve performed remote pair-programming with colleagues across the Atlantic using decent phone headsets and online collaboration tools for hours at a time. The net result of 2 days of remote pairing was finding and fixing about 10 extra defects in a thousand lines of code that neither of us would have found coding alone.
  5. Peer reviews – there is still a huge space for these in agile teams. But here’s the thing. Be really tough. A peer review is not a hurdle. It’s a shared learning exercise. Functional correctness is actually the smallest component of a peer review. You should trust your developers that far. But there’s a whole series of other aspects to review. See the joy of peer reviews.
  6. Small tasks – I once worked with an outsourced team who when taking work would disappear into a hole for 2 weeks and return with a single task in our configuration management system containing edits to 200+ files and multiple condensed edits to the files. My rule of thumb is one reviewable task per activity. If you’re going to add new functionality and refactor, that’s 2 independent tasks that can be identified and reviewed separately. This means you should be able to easily deliver 2 reviewable, closable tasks per day.
  7. Fast Builds – make it insanely simple for a developer to perform an incremental build that validates new code against the latest main code line. (small tasks are a big help here).  This includes the right subset of unit and functional tests. Aim for a target of a 30 second response time or less between hitting the button and seeing the first results.

In the next article in this series I’ll focus on “Tailing” – How do you start reducing the old defects.

10 Minute Test Plans

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Reading time ~2 minutes

Struggling to introduce TDD or Acceptance Testing? Here’s a really powerful simple first step that you can perform immediately – How to get your development teams “thinking” about tests and how to test with little or no negative impact and a few seconds setup time.

This assumes you’ve already broken out your story/feature/activity into developer-sized tasks.

  1. Push the keyboard away and get a sheet of A4 or Letter paper and a pen or pencil.
  2. Draw 2 lines to Divide the paper into 3 roughly similar sized areas.
  3. Pair up with the developer who’s going to work on a task.
  4. Start a timer –  you have 10 minutes.
  5. Spend 3 minutes listing out as many “pass” cases as you can think of between you – all those simple “happy path” things.
  6. Spend 3 minutes listing out as many “fail” cases as you can think of – bad inputs, exceptions etc.
  7. Spend 4 minutes thinking of all the boundary cases you can think of – e.g. date/time/time zone, rounding, location etc. Often these boundaries depend on your problem domain.
  8. That’s it – you’re done!

OK, this isn’t going to give you perfect code and it does take a bit of practice. Try not to agonize too much about whether these are unit, functional or acceptance tests for now. We’re still learning to fly here.

Much as standing up collaborating at a whiteboard uses a different part of your brain to coding; paring up, brainstorming and writing with a good old pencil & paper does a similar job. The discipline of not touching the code for a short period of time and thinking about how you’re going to test and what could go right or wrong will significantly improve the quality of what you produce – it usually makes the coding easier too.

Better still – you should now have your first unit tests to write! – pick the simplest ones you have on there and get them working! (I usually start with input validation. I know it’s not directly related to end user value but once I get a good grasp on inputs the rest fits in my head more easily.)