[sco1]

> you gradually add more and more files to the `mypy` invocation until you're eventually (hopefully) adding entire subfolders, and then maybe eventually the entire codebase

Rather than doing this, which does indeed seem like a headache, it may make more sense to skip import following at the very beginning until your core is typed so you can still enforce typing on the leaf nodes moving forward.

> Eventually you get to `#type: ignore` or `Any`s being thrown around to sidestep the CI pipeline, and your typing story has collapsed again

While there are some cases where this is truly the best option, ultimately you get to the point where you just don't allow this, otherwise what's the point of all the effort?

> and for people on the team not passionate about typing, they never worried about it <...> Asking the entire team to become Python typing gurus to sort out these issues was a non-starter.

The faster the core can be typed (and typed correctly), the easier it becomes for those who are less passionate. Presumably someone has done the calculus to determine that this effort is worthwhile, so while the team doesn't necessarily all have to reach guru level, they need to be convinced to continue the work. Removing barriers is huge for this, since as you've noticed once it starts being easy to ignore it's really challenging to stop ignoring.

[sesgoe]

> Rather than doing this, which does indeed seem like a headache, it may make more sense to skip import following at the very beginning until your core is typed so you can still enforce typing on the leaf nodes moving forward.

Yea, this is solid advice and something we did at one point. It's essentially strictly necessary for an older codebase.

> While there are some cases where this is truly the best option, ultimately you get to the point where you just don't allow this, otherwise what's the point of all the effort?

Again, true! We reached fatigue and gave up long before we hit the point where this would have mattered.

> The faster the core can be typed (and typed correctly), the easier it becomes for those who are less passionate. Presumably someone has done the calculus to determine that this effort is worthwhile, so while the team doesn't necessarily all have to reach guru level, they need to be convinced to continue the work. Removing barriers is huge for this, since as you've noticed once it starts being easy to ignore it's really challenging to stop ignoring.

I think this was probably my biggest failure in terms of the success of adding typing. I severely underestimated how long it would take to add typing info to some of the really old pieces of code, and it wasn't reasonable to expect to be able just to sit down and add types without delivering business value for an extended period of time.

My inexperience with `mypy` and the general typing ecosystem in python contributed significantly to the team ultimately reaching fatigue and deciding to give up on it (mostly).