Parse, Don't Validate (2019)

This principle is how pydantic[0] utterly revolutionized my python development experience. I went from constantly having to test functions in repls, writing tons of validation boilerplate, and still getting TypeErrors and NoneTypeErrors and AttributeErrors left and right to like...just writing code. And it working! Like one time I wrote a few hundred lines of python over the course of a day and then just ran it... and it worked. I just sat there shocked, waiting for the inevitable crash and traceback to dive in and fix something, but it never came. In Python! Incredible.

[0] https://pydantic-docs.helpmanual.io/

I've found this to be simply a matter of experience, not tooling. As the years go by I find the majority of my code just working right - never touched anything like pydantic or validation boilerplate for my own code, besides having to write unit tests as an afterthought at work to keep the coverage metric up.

Man, for a dev with as much experience as you’re claiming to have, this comment ain’t a great look.

I’d argue that the more experience you get the more you write code for other people which involves adding lots of tooling, tests, etc. Even if the code works the first time, a more senior dev will make sure others have a “pit of success” they can fall into. This involves a lot more than just some “unit tests as an afterthought to keep the coverage up.”

It's an immediate tell when someone makes statements like the one you're replying to.

It immediately tells me that they've never worked on large software projects, and if they have they haven't worked on ones that lasted more than a few months.

I apologize to folks reading this for my rather aggressive tone but I've been writing software for a long time in numerous languages, and people with the unit tests as an afterthought attitude are typically rather arrogant in fool hardy.

The most recent incarnation I've encountered is the hotshot data scientist who did okay in a few Kaggle competitions using Jupyter notebooks, and thinks they can just write software the way they did for the competitions with no test of any kind.

I had one of these on my team recently and naturally I had to do 95% of the work to turn anything he produced into a remotely decent product. I couldn't even get the guy to use nbdev, which would have allowed him to use Jupyter to write tested, documented, maintainable code.

I've worked on large scale projects for a long time. A large portion of the kind of code I've written is impractical or impossible to actually "unit test" e.g. Unity3D components or frontend JS that interacts with a million things. When something weird is going on I'll have to dig in with console logs and breakpoints.

On certain backend code where I am able to do unit tests, they do catch the occasional edge case logic error but not at a rate that makes me concerned about only checking them in some time after the original code, which I'll have already tested myself in real use as I went along.