Go Subtleties You May Not Know
7 comments
·October 13, 2025valzam
valzam
I guess as a corollary, Go really rewards writing the dumbest code possible. No advanced type shenanigans, no overuse of interfaces, no complex composition of types. Then you will end up with a very fast, resource light system that just runs forever.
theshrike79
And code with zero ability to do fancy trickery ("expressive" as some people like to say) is easy to read even if the codebase - or even the language - is unfamiliar.
Which is really handy when shit's on fire and you need to find the error yesterday. You can just follow what happens instead of trying to figure out the cool tricks the original programmer put in with their super-expressive language.
Yes, the bug is on line 42, but it does two dozen things on the single line...
porridgeraisin
Did not know about index-based string interpolation. Useful!
The part about changing a map while iterating is wrong though. The reason you may or may not get it is because go iterates in intentionally random order. It's nothing to do with speed. It's to prevent users from depending on the iteration order. It randomly chooses starting bucket and then goes in circular order, as well as randomly generates a perm of 0..7 inside each bucket. So if your edit goes into a bucket or a slot already visited then it won't be there.
Also, python is not an example to the contrary. Modifying python dicts while iterating is a `RuntimeError: dictionary changed size during iteration`
rowanseymour
Ah the old nil values boxed into non-nil interfaces. Even after 8 years writing go code almost every day this still bites me occasionally. I've never seen code that actually uses this. I understand why it is the way it is but I hate it.
amelius
I ditched Go after an evaluation years ago. I can remember it was an issue with nil pointers being non-intuitive that turned me off. And exception handling. A pity because the runtime and ecosystem/community seemed pretty good.
rowanseymour
It's fantastic concise language and standard library steered by people who are determined to keep it simple and intuitive... which IMO makes it all the more odd that it has this obvious foot gun trap where `!= nil` doesn't always mean what you might think.
Great list of why one can love and hate Go. I really did enjoy writing it but you never get the sense that you can be truly certain your code is robust because of subtle behaviour around nil.