Monday, February 13, 2017

Tuesday, December 13, 2016

Things an "Expert" C Developer Knows: Undefined Behavior

This is the first post in my series: Things an "Expert" C Developer Knows

The 2016 SEI CERT C Coding Standard [free download] gives  this definition of Undefined Behavior:
Behavior, upon use of a nonportable or erroneous program construct or of erroneous data, for which the C Standard imposes no requirements.
An example of an action that causes undefined behavior is signed integer overflow. Professor John Regehr at U of Utah has a blog post that gives several possible examples of what C compilers *could* do with this C statement in a program:
printf ("%d\n", (INT_MAX+1) < 0);
The possibilities Regehr lists include printing 0, 1, 42 or formatting your hard drive. While the latter won't actually happen, undefined behavior can cause data corruption and/or security vulnerabilities.

The CERT C Coding Standard lists. in Appendix C, all undefined behaviors in the current C standard: C11 (more formally known as: ISO/IEC 9899:2011) There are 203.

Since I've mentioned the C11 standard here, I should probably have a Things an "Expert" C Developer Knows post about C standards.

Things an "Expert" C Developer Knows...

In January, my engagement with my current client will be taking a real change in direction. Rather than being a software craftsmanship coach, I will be joining a large team as an embedded C developer.

In that vein, I submitted a talk to my employer's internal conference in February about things that developers need to know if they are going to say they *really* know C.

In preparation for that, watch for a series of posts from me on: "Things an "Expert" C Developer Knows"

Tuesday, November 15, 2016

Always TDD? But Certainly Not for Startups, Right?

I just read "Uncle Bob is Smoking His Socks", in which the author, Joe Rounceville, starts by taking issue with Uncle Bob's statement that you are not a professional software developer if you don't TDD. I understand how that statement makes people bristle. Rounceville goes on to suggest that there are contexts (in particular lean startup) that don't merit TDD. He goes as far as to suggest that TDD in that context might be "gold plating."

Of course, startups need to be ultra-agile and able to get fast feedback on experiments by getting work out in front of customers rapidly. There's an element of racing against time when a company has to achieve success with only a certain amount of capital to burn through. Startups need to be able to pivot quickly in response to what they learn in their experiments.

But people who argue against "always TDD" seem to think that they save time up front by not using TDD. Among experienced TDD developers, I have not found that to be the case. And well test-driven code allows for rapid pivots because it's easy to understand and different concerns in the code are not tangled-up among each other.

Another risk for startups that decide not to TDD is that prototypes tend to be pushed into production as-is. Many young companies have met serious pains when their initial rushed-to-market release could not handle the load that came with the product's rapid success. And there's the old saw that if you don't have the time to write it correctly the first time, you are not going to have the time to re-write it later.

The relationship between TDD and startups is tricky. Learning TDD takes time. It's not a simple matter to start using TDD if you aren't good at it. Developing software with TDD when you are new to it is slower than developing without TDD. There is a non-trivial learning curve. As a developer, I would not want to try to get good at TDD while working for a startup. And I personally would not want to join a startup if I wasn't already strong in TDD. And because of the ever-changing nature of the market, if I have a startup idea and I want to get good at TDD before starting on it, I'm likely to miss my window of opportunity. And if I develop my startup without TDD, I'm likely to end up with a hard to change and hard to maintain project that's prone to defects. So while Uncle Bob's statement about "always TDD" may sound dogmatic, I find the statement that "startups don't need / can't afford TDD" to be false.

Wednesday, October 19, 2016

The Importance of Saying "I don't know and..."

As a technical coach, especially when I am embedded in a team, it is hard to overemphasize the importance of using the phrase "I don't know," plus "let me go find out." or "I'll ask someone who I think can help us."

Being able to say "I don't know" is an important skill for developers if they want to be on a high-performing team. Without it, the team risks creating an environment of fear and delayed learning. So when I say "I don't know ..." as a coach, I am modeling behavior that will help devs succeed. And adding the second phrase models taking initiative. While many, perhaps most, devs are good at finding answers to things they don't know, there can still be cultural and other reasons why a developer might not step out of their usual domain.

If you have coaching responsibilities, either formal or informal, and you don't say "I don't know..." maybe ask yourself if you are missing an opportunity to model important behavior.

Tuesday, October 11, 2016

Guest Post: Thoughts on Re-evaluating Spring as a Framework for Building Well Maintainable Applications

I'm hosting this post for Brandon Zeeb, another software craftsman at Pillar

Thoughts on Re-evaluating Spring as a Framework for Building Well Maintainable Applications

Spring Boot is good for the general populous.  Not sure I’d recommend it for any greenfield development.

Spring Boot wraps up a lot of auto configuration that most developers, in my experience, do not understand.  Spring Boot enables 3-6 annotations, 2-3 of which you cannot enable outside of Spring Boot.  Those 3-4 common annotations explode out into at least 10 more annotations.  In total, all those annotations create a large number of beans very few developers know exist.  Only if you had been using Spring since version 2.0 and had followed it's growth through MVC (and its ViewResolvers) into the RESTy side (with its MessageConverters) will you know what it's actually doing.  In short, very few developers I've found can actually be effective within Spring.  If they try to find the right place for a thing, they spend more time reading documentation to find the right extension point (what base class does my @Configuration need to extend so that I can put this bean in the ContentNegotiationManager!?!?) and if they work around the framework they pay later when Spring works against them

If you're writing small micro services and you finish them and forget them I don't see a problem.

Though these days there are many more frameworks which are slimmer and offer a more obvious and easily testable environment which makes, in my view, Spring less relevant. (edited)

In short, I'm looking at more ala cart solutions.  An example might be using Guice (for IoC) with Vert.x 3.  There is pretty minimal frameworking, whatever your app does, you see very clearly.  The examples online don't show what I believe to be the best use of Vert.x (and Guice), they put all the codes in one file and say "hey look how easy this is!".  The Java APIs of Vert.x are incredibly clean, all interfaces, easy as hell to mock, which ties in well to properly abstracting and dividing the application into components

The built-in Hazelcast solves a lot of problems in architecture N-tier apps have.

Brandon Zeeb:
Twitter: @phasebash