The joys of maintenance programming (2011)
I love maintenance programming. I love legacy programming too. I have a story where the two worlds collide.<p>At my last job I had to work with a PowerShell codebase that `cloc`ed in at over 100,000 lines, and was absolutely ancient to boot, having been added to in bits and pieces by sysadmin after sysadmin over the course of 12 years total, in 3 different human variables-and-comments languages, all of whom were Windows power users with very clear ideas of what needed to be done, but also all of whom were very clearly learning to program for the first time, at least in the wonky PoSH paradigm. AKA: Classic big ball of mud situation. Every new customer had to have their details run through this codebase, however, and I saw the potential to eventually boil this down to a simple 6- or 7-parameter cmdlet (PoSH for &quot;shell script&quot;). I got my undersized chisel and toy hammer and got to work.<p>In some ways starting work on the proj felt more like beginning to dig into an ancient COBOL database in a System&#x2F;360 mainframe than anything resembling the state of the art in 2023, or even 2011. There was a single VM that everything had to run on, and the script couldn&#x27;t even be called remotely via SSH because the only way in was via a web browser based remoting session. The connection was spotty and would often drop halfway through coding in there in my dinky little Notepad++ session, requiring minutes of reauthentication just to get back to work. Unit testing (which PowerShell had a surprisingly good third party library for, called Pester) was out of the question. And: There was no version control! No wonder it got to 100k lines - most of the code was being entirely unused! But what?<p>The first few Saturdays I spent didn&#x27;t go very far. I was mostly trying to figure out where the logic even began and ended in this mess of spaghetti. But eventually I started to piece together an overall structure for the thing. I made a pact to myself not to delete any of the many, many files that had accrued over the years until I knew every file that the code would touch first. I started doing some lightweight encapsulation with the -WhatIf flag, and with firebreaks (sticking `return` after each tiny function) so I could work on one linear piece at a time, and gradually tiptoe my way forward to the finish line. Eventually I got there, and managed to strip the whole thing down to about 1500 lines.<p>The joy of this kind of programming is that, even if you don&#x27;t start with regression tests or modern practices, you do know from having ran through the original process a million times <i>exactly</i> what the end product is supposed to look like. Since no one is paying attention to your refactoring work in the first place, you&#x27;re allowed to take your sweet time. To me it was obvious this mess of code was going to become a blocker for the business at the pace we were going: We were a SaaS, and yet we had to manually provision customers behind the scenes like this, in a process which took days to weeks? And we didn&#x27;t even have a proper CLI we could call for this? Jackpot!<p>I left the company about 2 months after wrapping this project up and demoing it to my coworkers in search of better pay, but I&#x27;m really glad I got the chance to take such a fearsome codebase and tidy it up like that. There is just something satisfying about that kind of work, it&#x27;s like gardening. I also got really, really good with Notepad++&#x27;s find and replace across all files functionality. There is in fact a skill to it! (Mostly that you should always, always find and replace the longest strings first!) Although I think these days I&#x27;d probably reach for a similar function in vanilla vim first, or even in bare `sed` if I was feeling gutsy.<p>(I&#x27;d end with &quot;If you, dear reader, are in a similar PowerShell quagmire you need someone to pull you out of, I&#x27;m available for consulting at $X00&#x2F;weekend&quot;, but alas. My weekends for the next few months are already sworn to another equally wonky project for my current employer. At least I&#x27;m getting overtime this time. ;) )