pyvista-mypy-plugin

Mypy plugin for the PyVista project.

This plugin is primarily used for type-promotion between related classes that do not inherit from each other. For example, the abstract class pyvista.DataSet does not inherit from vtk.vtkDataSet, and will generate type errors wherever a vtk.vtkDataSet is expected. Without this plugin, the following is a type error:

from pyvista import DataSet
from vtkmodules.vtkCommonDataModel import vtkDataSet

x: vtkDataSet
x = DataSet()  # error: Incompatible types in assignment (expression has type "DataSet", variable has type "vtkDataSet")'

(Note that the example above is not valid at runtime since DataSet is an abstract class and cannot be instantiated.)

With this plugin, DataSet is promoted as type vtkDataSet, allowing DataSet type to be used wherever vtkDataSet is used.

Installation

Dependencies:

• mypy
• pyvista
• vtk

Install it with:

python -m pip install pyvista-mypy-plugin

Alternatively, add pyvista-mypy-plugin as a project dependency wherever mypy is used, e.g. as an optional dev requirement in pyproject.toml:

[project.optional-dependencies]
dev = ["mypy", "pyvista-mypy-plugin"]

Usage

To enable the plugin, it must be added to your project's mypy configuration file. E.g. add the following to pyproject.toml:

[tool.mypy]
plugins = [
  'pyvista_mypy_plugin',
]

Testing

First, install pyvista-mypy-plugin with dev requirements:

python -m pip install pyvista-mypy-plugin[dev]

To run the tests, execute:

pytest