Programming

A few days ago I published a short post about two bugs I wrote while developing the C++ external scanner for my TLA⁺ tree-sitter grammar. Reactions were mixed! Many people were supportive, but there were of course the usual drive-by claims by developers that the bugs were trivial, they would’ve found & fixed them inside of 20 minutes, and I was laughably incompetent for having written them in the first place. Maybe so! I’m a fan of formal methods primarily so I don’t have to be a genius to write correct code. In that same vein of building tools to save us from ourselves, one user suggested building the tree-sitter grammar with the LLVM address & undefined behavior sanitizers enabled. I’d used valgrind a long time ago but had never played around with sanitizers. I was also doing some closely-associated work to build the grammar for fuzzing with LLVM’s libFuzzer, so it seemed a fun detour to check whether those sanitizers would have saved me days of debugging pain!

Here’s a short post about two bugs I wrote while writing C++ code for the external scanner of my TLA⁺ tree-sitter grammar. External scanners use handwritten C or C++ code to parse the non-context-free parts of your language. I’ll try not to dump on C++ too hard but both of the bugs are highly ridiculous and exemplify why I hope to write as little of the language as possible for the rest of my career. These aren’t bugs with C or C++ themselves (although honestly this point could be argued) but I share them in the hopes someone finds entertainment in my misery.