Friday, December 30, 2011

The benefits to “check in early and often”

I am a huge advocate of checking in early and often. I’ve seen many a project get burnt by the developer who saves 3 weeks of work for a single “glorious” check-in.
I favor frequent check-ins because it’s:
  1. Cheaper integration. Someone once said “Integration is pay me now or pay me later”, and I find it much easier to pay now. Especially with automated builds and continuous integration, it’s much easier to check in 10 little changes than 1 big change (Sometimes I think of it like being easier to hold my breath for 30 seconds, ten times, as opposed to holding it for 5 minutes straight). Why? Because with bigger changes, you inevitably get farther out of sync – especially on critical shared files – and there’s more to forget.
  2. More objective measure of what you really have: Code that isn’t checked in, that just works on a developer’s machine, doesn’t really exist. They might as well say “it works in my head”. Once you actually get the code past a build server’s policy, then we can see what’s really there.
  3. Earlier Detection: We all know it’s cheaper to fix a bug or redesign the sooner you catch it. I’d rather developers check in code early so we can quick detect things (“why is there 5000 lines but no tests?”)
  4. More Modular: Checking in 10 chunks of code, where each one works, implies more granular and modular code. I.e. code that can at least be split into multiple check-ins is more modular than code that can’t be split at all.
Of course there’s always exceptions (you do a massive refactoring, etc…), but those should be the exception, not the rule.
Most of the time, in my experience, large check-ins by developers means something bad – spaghetti code, tightly-coupled code, code that was trying to hide under the radar until right before the deadline and then the developer says “oops, I just don’t have time to change it”, or something like that. Think of it like this: there is zero benefit to you to have to wait one month before seeing what a developer is doing, but there is benefit to early detection of code, so risk-reward wise it’s better to check-in early.
Note that for these purposes, a shelve set is not the same as a check-in. Shelvesets are private, and hence deliberately avoid the benefits listed above (which some say is a feature). For example, you mostly likely don’t have builds on a private shelfset. For a developer to say “I put my 20,000 lines in a shelveset” is misguided– use a branch instead if you need to.
So how to encourage check-in early and often?
You could write a whole chapter on this, but here's a short answer: You can explain the benefits so some developers are internally motivated, or you can make it official policy so that other developers are externally “motivated”. You can leverage the TFS Code Churn tables to automatically monitor activity, or even just view check-ins in Team Explorer, to see how often a developer checks in and how much code has changed. If a developer or contractor insists that they need to wait 1 month to check-in their code when “it’s ready”, you’ve got problems, much like if a developer insisted they didn’t need to follow any other policy or good practice.

Monday, December 5, 2011

Is development for sissies?

I was reading the book "Tales to make boys out of men" (I have 2 young ferocious gorillas boys). It was filled with adventurous stories of courage and valor who fought battles in the jungle or trekked through the frost-bitten Antarctic. Then here am I, a software engineer, essentially doing a "desk job" in an air-conditioned office with free coffee.
Sometimes I see people who have two categories: "tough-guy" jobs like fighter pilot, football player, or astronaut,  and "sissy" jobs like software engineer sitting behind a desk. What do I tell my impressionable kids?
I see it like this. "Tough-guy" jobs are honorable, and you certainly need them. But don't dismiss a "desk job" as being a sissy. Many IT engineers need to work with the most ferocious, dangerous, lethal, destructive animal on the planet – other people.  People inevitably have competing demands and interests, there are ruthless sharks out there, and any job that must constantly deal with people cannot, by definition, be a sissy job.
Second, developers also must work with the most uncaring and cold-hearted beast ever to exist – the compiler. The compiler doesn't care if you've had a bad day, if your code should work, or if you've spent a hundred hours on a 5 minute task. It has no grace. Such an inhuman vacuum is not the field of sissies.
Furthermore, other people are depending on the IT engineer's work. You could have a million customers using your financial application, or a billion dollars of revenue flowing through your processing system. Hackers attack your system every day. And the system has got to work. To have that sort of responsibility is not sissy-like.
Lastly, software engineering is so complex that you inevitably make mistakes (sometimes really big ones) – and then need to own up to them. That takes courage.
Ok, it's still not Rambo, but software engineering is not for the weak.

Friday, December 2, 2011

10 Reasons why the build works locally but fails on the build server

This is a braindump:
1.       Developer did not check all the files in, or developer doesn't have the latest files (sometimes TFS hiccups getting latest dlls files).
2.       Different modes (release vs. debug). Either #if DEBUG, or project is unmarked in configuration manager.
3.       Different bin structure - each project gets its own (Default for visual studio), vs. single shared bin for all (default for TFS). This is especially common when different versions of the same assembly is referenced in multiple projects in the same solution.
4.       Different platform/configuration
5.       The build is running other steps (perhaps a packaging or command-line unit tests)
6.       Different bitness, say developer workstation is 64-bit, but build server is 32-bit, and some extra step breaks because of this.
7.       Rebuild-vs-build. Developer not running a rebuild. Hence there's an error in creating a dll, but it already exists on dev machine due to some other process, but build server fails.
8.       Workspace mapping is incorrect – TFS not getting all the files it needs
9.       Unit test code coverage – visual studio (at least 2008) can be very brittle running command line unit tests and code coverage.
10.   Treat warnings as compile errors – depending on your process, the build server may fail on these, but Visual studio may only flag you with a warning (which dev ignores)