Hello a coworker of mine is running into some trouble when u

Question

Hello a coworker of mine is running into some trouble when using Pants In our `pants toml` file we have the following ``` python interpreter constraints = CPython==3 9 ``` However when he runs Pants commands he sees the following line ```Bootstrapping Pants using usr local bin python3 7``` This is problematic because we use Python 3 9 features which is causing his runtime to fail What is the reason that Python 3 7 is being used here

bitter-ability-32190 · Answer

Pants uses Python to run itself Your first config is the ICs Pants should use to run your code It should be OK in most cases that Pants runs itself with 3 7 but your code with 3 9 What s the error In a plugin

bitter-ability-32190 · Answer

plugins and macros are those places where what version Pants runs itself with matters

cold-soccer-63228 · Answer

Yup in a plugin I do the following in there ```from typing import Final```

cold-soccer-63228 · Answer

And `typing Final` isn t valid until Python 3 8 confused

bitter-ability-32190 · Answer

Ah yeah might want to do `from future import annotations` and then also `if TYPECHECKING from typing import Final`

bitter-ability-32190 · Answer

Eventually Pants won t use the user s Python to run itself <https github com pantsbuild pants issues 7369> eventually stuck out tongue

cold-soccer-63228 · Answer

Awesome I think that fixes it Thanks Josh

happy-kitchen-89482 · Answer

Ah right Pants can run on 3 7 but run your code on 3 9 no problem think of that 3 7 as an implementation detail of Pants The only time this isn t quite true is in repo Pants plugins

happy-kitchen-89482 · Answer

Because those are running in process in Pants

happy-kitchen-89482 · Answer

But you can always modify your ` pants` script to modify the interpreters it s willing to bootstrap with

wide-midnight-78598 · Answer

<https www pantsbuild org docs options pantsrc file> `pants rc` is definitely your friend on this one My Xcode python get s periodically pulled in for some reason At least it used to