Methods That Break Mysteriously

[capturts]

How do things break when you don't change them

I've spend the best part of an hour trying to fix something that I know I haven't changed in anyway. I can't even find the problem, some data just vanishes somewhere in a particular method and it's annoying. I'm not after help I just don't know how it got broken.  Has anyone else come across this phenomena? 

[Nox]

Well triple-check, maybe you missed something

And if it's not there then it was caused by a change you did elsewhere - that's why usage of global or static stuff it's unrecommended, these are not exclusive causes, just the more prone to. So check not the method itself, but everything it uses

Bugs or HW errors are extremely rare, it's most often not the case

Which language? Are you using APC/Eacc/Zend Opt. or something?
Also stuff like a need for volatile keyword in C, compiling optimizations, race conditions screwing up, but I doubt it be the case, just throwing some examples where stuff can go weird

It's often the tiniest stuff that can cause a bad behavior, a missing dot or something can screw the script up

[capturts]

YAY! Figured it out. The method hadn't changed the data from the database was coming back as an object when it should've been an array 

[capturts]

Well triple-check, maybe you missed something

Triple... I looked at this about 1000 times   

Thanks for the suggestions Yes It's often something small that breaks things. And in this case the error was elsewhere. If I had looked carefully at the data I would've seen the problem in 2 seconds flat.

Basically the data for a battle is stored in the database as json and I guess somewhere along the lines I'd accessed it as if it were an object. I think this is one reason I'm not so keen on the duck-typing in PHP. It sounds handy to be able to chop and change a variable to use it as an integer and then a string and then later on reuse the variable as an object but if it were strict typing the error would've been more obvious.

[Chris]

How do things break when you don't change them

I've spend the best part of an hour trying to fix something that I know I haven't changed in anyway. I can't even find the problem, some data just vanishes somewhere in a particular method and it's annoying. I'm not after help I just don't know how it got broken.  Has anyone else come across this phenomena? 

Multiple times My personal theory is that the gnomes that live inside CPU get drunk from time to time And that's the cause of these mysterious things.

[capturts]

Well, not sure about gnomes, but definitely something seems to break stuff when you're not looking.

On a serious note, I find this is where the worst 'hacks' appear in my code. Something is working great, I work on a different bit of project and then come back and it's broken. Then I find myself adding stupid bits of code that adds 1 to an array index and then takes it off again 5 lines down.

[Harkins]

Write automated tests and use version control software and these problems will quietly vanish. I spent the first ten years of programming plagued by them, now I don't know the last time I saw stuff randomly break.

I'm guessing you're using PHP, SimpleTest looks like a straightforward tool. If you're on Windows, git is probably a big pain in the ass, but TortoiseSVN makes Subversion easy to use.

Let your tools do all the boring, tedious bookkeeping so you can write code.

[Mutant]

Another vote for automated testing. It's not an easy thing to do (it takes years to learn how to do properly, just as it does to program). But once you learn how to do it right, it's amazing how much easier certain things get. I can't even write code without some tests to fall back on now.

[capturts]

Yes, PHP in this case. I'll take a look at simpletest, thanks

[gnoh]

Along with automated testing,  also use assertions to valid your assumptions about the parameters.