A flake8 plugin for QGIS3 python plugins written in Python.
Made with Cookiecutter template cookiecutter-flake8-plugin. Inspired by flake8-simplify.
Install with pip:
pip install flake8-qgisJust call flake8 . in your package or flake your.py.
| Rule | Description |
|---|---|
| QGS101 | Avoid using from-imports from qgis protected members |
| QGS102 | Avoid using imports from qgis protected members |
| QGS103 | Avoid using from-imports from PyQt directly |
| QGS104 | Avoid using imports from PyQt directly |
| QGS105 | Avoid passing QgisInterface as an argument |
| QGS106 | Avoid importing gdal directly, import it from osgeo package |
Please check the Examples section below for good and bad usage examples for each rule.
While it's important to adhere to these rules, there might be good reasons to ignore some of them. You can do so by using the standard Flake8 configuration. For example, in the setup.cfg file:
[flake8]
ignore = QGS101, QGS102Avoid using from-imports from qgis protected members
An exception is made for importing qgis._3d (since flake-qgis 1.1.0). The underscore in the package name is used to prevent the name from starting with a number, ensuring it is a valid package name.
Protected members are potentially unstable across software versions. Future changes in protected members might cause problems.
# Bad
from qgis._core import QgsMapLayer, QgsVectorLayer
from qgis._core import QgsApplication
# Good
from qgis.core import QgsMapLayer, QgsVectorLayer
from qgis.core import QgsApplicationAvoid using imports from qgis protected members
An exception is made for importing qgis._3d (since flake-qgis 1.1.0). The underscore in the package name is used to prevent the name from starting with a number, ensuring it is a valid package name.
Protected members are potentially unstable across software versions. Future changes in protected members might cause problems.
# Bad
import qgis._core.QgsVectorLayer as QgsVectorLayer
# Good
import qgis.core.QgsVectorLayer as QgsVectorLayerAvoid using from-imports from PyQt directly
Importing directly from PyQt might create conflict with QGIS bundled PyQt version
# Bad
from PyQt5.QtCore import pyqtSignal
# Good
from qgis.PyQt.QtCore import pyqtSignalAvoid using imports from PyQt directly
Importing directly from PyQt might create conflict with QGIS bundled PyQt version
# Bad
import PyQt5.QtCore.pyqtSignal as pyqtSignal
# Good
import qgis.PyQt.QtCore.pyqtSignal as pyqtSignalAvoid passing QgisInterface as an argument
It is much easier to import QgisInterface, and it's easier to mock it as well when writing tests. This approach is not however documented properly, so the API might change at some point to exclude this.
This rule can be excluded safely since this is only a matter of preference. Passing iface as an argument is the documented way of getting QgisInterface in plugins. However, it requires writing more code.
# Bad: iface passed as argument
def some_function(somearg, iface):
# do something with iface
# Good: iface imported
from qgis.utils import iface
def some_function(somearg):
# do something with iface# in classFactory the passing is OK, since QGIS injects it
def classFactory(iface):
# preferably do not pass the iface to pluginAvoid importing gdal directly, import it from osgeo package
Importing directly from gdal might create conflict with different gdal versions
# Bad
import gdal
import ogr
# Good
from osgeo import gdal