Tuesday, December 20, 2016

Implicit Time-Based Coupling - Inside a Class.

Imagine if you would a class in an object-oriented language.

Notice that x()and y()are not constructors.

Now, a "good" user of an instance of Trouble will do something like this:
t.x(); // always call x() before y()  
Whereas a naive user of the class might do something more like this:

In this case the value of i1 (used by function y) is either undefined or possibly some leftover value from earlier uses of instance t.

How Do You Know?

The functions x and y have an implicit temporal binding.  When you look at the object diagram, or if you use code completion, nothing you see will tell you that you must call x before y.


  1. You don't know about it, and have been "just lucky" so far
  2. You don't know, and are currently making bugs you don't know about
  3. You know because you've read the code from top to bottom and understand the implicit temporal coupling. 
  4. You copied someone else's example after yours didn't work, and you don't know why it calls x() before y(), but dammit it works.
  5. You've spent considerable time in trial-and-error and treat x() as a magic incantation.
  6. Someone told you.
Of these, I'm most afraid of 1 and 2. These are hidden dangers, and eventually there is going to be a nasty surprise for someone -- possibly the customers.

If one is working at a large scale (dozens or hundreds of people using Trouble) then 3 is asking far too much. Who can afford to carefully read the implementations of all the classes they use, and keep track of when variables are set and used? You can't afford to have 20 people wasting time on this, in hopes that they might spot the one or two special classes who rely on temporal coupling. 

While it's easy to blame all "bad code" on a lack of discipline, we find that it is more productive to fix the tricky coding practices that require a high level of discipline. 

You will always find it more scalable and productive to make the work easier than to work harder

Don't work people harder. 
Make people's work easier!

Number 4 is also a nightmare at scale. Code duplication is the king of code smells, but here people are copying code because they feel like they can't afford the time to understand the code they're producing. That's awful. I don't blame the copiers, they're in a situation where they're asked to put out effort they can't afford. But I would rather they investigated instead of copying blindly. 

Number 5 is too much to ask.

Number 6 (someone told you) is not bad in and of itself. Communication is good. But here the communication is how to work around a problem in the code so that you don't have to fix it. Perfectly reasonable-sounding if you can't change the code itself, but questionable in general. How safe are you if the only thing protecting you from disaster (in the hazards of 1 & 2, or the time sinks of 4 & 5) is oral tradition. 

At Scale?

While solutions often scale poorly, we find that problems always scale very well, indeed.

The ideal when programming in groups and at scale is that you demand the least from each other, so that you can all accomplish the most.

At scale, you want to build code so it is easy for other people to do what works well, and avoid hazards and risks along the way. 

All implicit couplings are risky, including (but not limited to) duplication of algorithms. Every fact, every algorithm, every bit of knowledge should have a Single Point of Truth in the application. 

Here the design of the code is such that the "point of truth" (knowledge that x() must be called before y()) is distributed to every bit of code which needs to call function y.  

It demands duplication of code in the callers, and demands a higher level of "due diligence" from the programmers. 

At scale, this small feature becomes a big problem. 

So now what?

There usually ways to fix this problem.  There are also ways to cope with not solving it. 
  • Make y call x.
  • Make incorporate y into x, if y really only means "complete work started in x."
  • Have y set i1 directly.
  • Initialize i1 to a null or indicator value in the constructor, and add a guard clause in y which will throw an exception if i1 has not been given a meaningful value.
  • Create a new function that calls x() and then y() -- and rename function y to something that sounds dangerous to use, like unsafeY or  innerYtoBeUsedOnlyIfI1HasBeenSet.
  • Rename x to prepareForY.
  • If only x and y use i1, then it is a temporary field (code smell) and you should refactor it away normally.
  • Add an optional parameter to y, which is the value you want i1 to have. Combine this strategy with the guard clause idea, above.
  • Build a wrapper class around the Trouble class, so that the wrapper is the Single Point Of Truth about how the Trouble class should be handled. Make the Trouble class private, internal, or otherwise hidden. 
  • Go find or make a replacement class for Trouble.  Who needs it? 
  • Tolerate Trouble by setting a cron job to search for invocations of y. Review any new uses of the function immediately.

You can probably come up with a dozen more ways to improve the situation.

But the important thing is that we can recognize implicit temporal cohesion and its role in making code expensive to write, and that we take steps to make the work easier if we want to accomplish more work sooner. 

And who doesn't?

Wednesday, December 14, 2016

The Employee's Unapproved Feature

Your employee “wastes” time doing a feature you didn’t approve.

You find out about the feature as it is being released to customers.

Customers are enthusiastically happy with the new feature. Thrilled, in fact. They complement you and your team!

Do you

  • reign in your rogue employee 
  • give her more influence in deciding future features
  • ignore this one infraction since it worked out okay
Quickly write down your answer and then read the next paragraph.

Okay, you've written down your answer. It doesn't matter so much to me what answer you chose, or if you chose one not given above. What I want to know is what were the principles on which you based your answer. How important was the outcome v. the process? How crucial is conformance and predictability of action v. success of action and engagement? Was the employees act one of insubordination or service to customers? Which is more important? 

If you complete this little meditation and change your answer, what did you change it from and what to? And why? 

I'd love your answers here, or if you prefer to be anonymous at my sayat site.

Thursday, December 1, 2016

TDD: Start With A Failing Test

The question was asked:
In Test-Driven Development, what does it mean to start with a failing test? 

This is not a complicated question, so let me give the short answer:

  • Write a test that can't possibly succeed because you have not yet implemented the feature; but which would succeed if the part of the feature it's testing were written.
  • You want it to be a good test: clear, obvious, simple, discrete.
  • You want it to fail, so you see what the error message will look like -- whether it will provide enough information when someday it fails unexpectedly.
  • Then you write enough feature that the test passes works (but not the whole feature).

The idea is like a video game. You write a test, which is your first challenge. Then you beat that challenge and save your game (to version control) so you can come back. You layer on the challenges until you've beat the game (written the feature).

There is more to the TDD cycle, but this is enough to answer the one question.

BTW, the same "accumulation of phases that work" is the preferred approach to writing stories, which add to features... the whole world of test-driven is about thin, tested, integrated slices continually being built and integrated.

Monday, November 14, 2016

For those of you keeping track...

Sometimes I receive bizarre statistics in email. So:

Rank of world for agileotter.blogspot.com is 14,111,324

It sounds like my blog has ranked this world the 14-millionth favorite, but I think it means the opposite.

I have plenty of margin here so that I can improve without running out of space. 


Wednesday, November 9, 2016

Support Each Other

if we all could put curiosity and interest in others over the warm self-righteous glow of disdaining and judging, then we could do all things.
As long as we go about magnifying the differences and heaping shame on people who see things differently, we will continue this path.
It’s a choice.
Maybe your vote isn't the most important choice you could make this month.

Wednesday, November 2, 2016

But In The Real World

An old story I’d almost forgotten resurfaced for me today.

A guy who spent his entire career in the same company, in the same state, mostly in the same building, mostly with the same bosses who were of the same management philosophy once corrected me when I was talking by saying “yes, but in the real world…”

It was the first time it became clear to me that “in the real world” could not only suggest that my views are naive, but that the speaker is from a very specific (and perhaps naive) context.

It didn't have to be. Sometimes I am naive, but not every time.

"In the real world" only meant that my experiences did not coincide with his, and therefore my sense of cause-and-effect seemed far different from the "laws of work" where he spent his time.

I must have looked like an alien to him, as he did to me.

The things I said about trust, team work, values, and practices sounded entirely unworkable because they didn't follow the rules of his control-based organization where everyone knows that people only do their work because they have no choice. All this "hippy crap" didn't make any sense.

Except that it always has made sense and worked in my experience.

Travel Broadens One

I've always been pretty mobile. I've been with a lot of really great consultancies even before the one that makes it possible for me to travel the world these days. All of my clients and all of my companies have always had things to teach me.

Some of the things I learned were pretty context-specific, and didn't carry from one real-world experience to the next. Some were more universal, but were moored to a point in time or a way of working that has since become quaint.

Some things I learned, the most important things, have weathered a lot of storms and changes in fashion. As far as I know, they may be universal. They're certainly well-represented in ancient wisdom and sacred texts. But I can't assume the universal reality of them either.

Being in a lot of organizations and helping to solve many technical and cultural issues has granted me a lot of relatively brief but intense exposure to a lot of companies and contexts.

Unlike my friend above, I didn't stay in any one of those contexts for decades. I don't know what it's like to have only a very deep exposure to a single culture. I don't know what it's like to have all your history, relationships, and experience tied so deeply to your neighbors and lived so deeply in your daily work. Our worlds are very different, indeed.

At one point, when we were in mid-transformation he enlightened me to his context, explaining that he avoided upset (no matter what) because "these people are your neighbors and you have to live with them."

I forgot that not everyone is mobile and not every community is temporary. I was (in this case) naive to his context.

How Tiny Our Perception

I've written about getting through to each other before, and how experience and mindset controls how we hear others' words and how we choose our own. Sadly, this is one of those moments where we would need to look each other in the eye if we were to come to any kind of certainty that we're communicating this important idea, but I'll try:

"There are more things in heaven and earth..."

All our “real worlds” are tiny one-person slices, and yet all these contradictory experiences are "real".

 If you live in the city, the country life seems the naive and unreal one. If you live in the country, you see city people as strange and out of touch.

But we're tiny and self-involved beings. We tend to measure tallness and shortness of trees by our own height. A "long time" is some proportion of our own lifespan; just ask a 5-year-old how long it is between birthdays or Christmases.

If my life is one person's slice out of the whole of existence and the whole of history, it is a very small measure of reality. It's impossibly thin.

So when one of us calls out "in the real world" we hear them as invalidating our experiences (oh, self-involved self!) but really it's just a curiosity space.

And then we find out that they have things to teach us, too.

Not So Easy

"In the real world" is a pretty arrogant thing to say, and frankly triggers me a bit.

I'd like to say I was past this, but I still have to process the upset and forgive the arrogance of the speaker and this listener.

After I process that all I can reorient, enter into curiosity, and start to communicate again.  But I have to take the time still.


Friday, September 30, 2016

Political Correctness and Truth

Yeah, I know that title is going to be a bit inflammatory, and everyone knows what they expect when they see it up there. But that's okay.

My topic is really about such things.

I want you to consider:

  • Saying hurtful things
  • Not being politically correct
  • Telling the truth
What I want you to consider is that these are three entirely orthogonal concepts. One can make statements which are any one of the above, without being the others.  

One may easily say offensive things which are entirely politically correct. It's a common event on the internet to see people shaming others in the name of Political Correctness (which should be all about being fair and kind to others, but outrage is virtue these days). Some of the shaming statements could be true, and some could not be true. 

One can certainly state truths in kind ways, full of compassion and empathy. Even ugly truths can be delivered in considerate ways. 

One can say things that are true and not PC, but they don't have to be said in a way that is deliberately hurtful. 

I'm only bringing this up because I keep seeing a growth in people saying hurtful things and claiming that they're true because they're not PC. 

And I see growth in people saying hurtful things because they are PC. And because they're PC, claiming the power of truth.

Offensiveness is not evidence of correctness.

I'm very concerned to see people look for others' hurt feelings as confirmation of the rightness of their position. Being cruel is a far cry from being right.

And of course, "telling the truth" is a ticklish thing in the best of times. Truth is more present in mathematical formulae than in human interaction.  What I think is true is subject to so many biases and conflicting theories and personal imperfections.  

And yet, I hear things being said about groups or demographics or whole populations that are hurtful, are not politically correct, and are far from certainty or truth.

I suppose I would like everything I say or hear to be authentically what the speaker believes, while being as kind and empathetic as possible, and not worry about how it plays in PC.

But if one doesn't have certainty in their virtues of kindness and curiosity as "true north" values, then I see value in at least observing and considering Political Correctness in public discourse.

This post is 
  • intended as non-hurtful (let me know if it's so)
  • pretty safe, in a PC kind of way
  • authentic,  and "true" as far as I can tell