I disagree, dependencies can change causing types to change which requires you to alter hundreds of lines across multiple repos.
Each new line or character is a line to maintain, there is a cost associated with that. Tests have costs but are extremely valuable, they are a no brainer to me, types are way less obvious.
I have spent a lot of time maintaining python types. I have no idea how many bugs it has prevented. I am not sure it is a large number.
I know there have been bugs in types, bugs in mypy and dependency changes which created work which only existed because types were in place. There have definitely been days worth of types maintain.
There are the extra type imports, extra time to run tests and integration tests etc.
It is not as straightforward as you might initially assume.
I have been developing almost exclusively in Python for the last 4 years (occasional C#, Java and PHP) and although my entire team disparages PHP it is really quicker and fewer characters for most stuff.
Luckily IDEs can auto add the imports, but sometimes a slightly mistyped piece of code auto adds an import I need to delete, I love avoiding imports and circular imports in PHP. The other nice thing is avoiding random python behaviour differences in MacOS, Windows and Ubuntu. Code that works fine in CircleCI but not locally. Works on a Mac but not on windows etc… I didn’t experience that with PHP.
Not sure there are a huge number of long term PHP devs who switch to Python or the other way around to have a reasonable opinion.
Each new line or character is a line to maintain, there is a cost associated with that. Tests have costs but are extremely valuable, they are a no brainer to me, types are way less obvious.
I have spent a lot of time maintaining python types. I have no idea how many bugs it has prevented. I am not sure it is a large number.
I know there have been bugs in types, bugs in mypy and dependency changes which created work which only existed because types were in place. There have definitely been days worth of types maintain.
There are the extra type imports, extra time to run tests and integration tests etc.
It is not as straightforward as you might initially assume.