Setting up a Project
We start by creating an empty project directory and setting up a virtual environment:
$ mkdir my_project && cd my_project
$ python3 -m venv ~/.venvs/venv
$ source ~/.venvs/venv/bin/activate
(venv) $ pip install pyre-check
Next, we teach Pyre about our new project:
(venv) $ pyre init
This command will set up a configuration for Pyre (.pyre_configuration) as well as watchman (.watchmanconfig) in your project’s directory. Accept the defaults for now – you can change them later if necessary.
Running Pyre
We are now ready to run Pyre:
(venv) $ echo "i: int = 'string'" > test.py
(venv) $ pyre
ƛ Found 1 type error!
test.py:1:0 Incompatible variable type [9]: i is declared to have type `int` but is used as type `str`.
This first invocation will start a daemon listening for filesystem changes – type checking your project incrementally as you make edits to the code. You will notice that subsequent invocations of pyre will be faster than the first one.
For more detailed documentation, see https://pyre-check.org.