add mypy as static type checker

Author: Julian Dehm

.github/workflows/django.yml

@@ -88,6 +88,7 @@ jobs:
           isort --diff -c meinberlin tests
           python manage.py makemigrations --dry-run --check --noinput
           flake8 meinberlin tests --exclude migrations,settings
+          mypy -p meinberlin tests
       - name: Coveralls
         env:
           GITHUB_TOKEN: ${{ secrets.COV }}

.mypy.ini

@@ -0,0 +1,10 @@
+[mypy]
+warn_return_any = False
+warn_unused_configs = True
+disable_error_code = import-untyped
+exclude = settings/|migrations/
+
+[mypy-meinberlin.config.settings.*]
+follow_imports = skip
+
+

Makefile

@@ -177,6 +177,7 @@ lint:
 	EXIT_STATUS=0; \
 	$(VIRTUAL_ENV)/bin/isort --diff -c $(SOURCE_DIRS) ||  EXIT_STATUS=$$?; \
 	$(VIRTUAL_ENV)/bin/flake8 $(SOURCE_DIRS) --exclude migrations,settings ||  EXIT_STATUS=$$?; \
+	$(VIRTUAL_ENV)/bin/mypy -p $(SOURCE_DIRS) ||  EXIT_STATUS=$$?; \
 	npm run lint ||  EXIT_STATUS=$$?; \
 	$(VIRTUAL_ENV)/bin/python manage.py makemigrations --dry-run --check --noinput || EXIT_STATUS=$$?; \
 	exit $${EXIT_STATUS}
@@ -213,6 +214,7 @@ lint-python-files:
 	$(VIRTUAL_ENV)/bin/black $(ARGUMENTS) || EXIT_STATUS=$$?; \
 	$(VIRTUAL_ENV)/bin/isort $(ARGUMENTS) --filter-files || EXIT_STATUS=$$?; \
 	$(VIRTUAL_ENV)/bin/flake8 $(ARGUMENTS) || EXIT_STATUS=$$?; \
+	$(VIRTUAL_ENV)/bin/mypy -p $(ARGUMENTS) || EXIT_STATUS=$$?; \
 	exit $${EXIT_STATUS}
 
 .PHONY: po

changelog/_1113.md

@@ -0,0 +1,3 @@
+### Added
+
+- add mypy static type checker

docs/linting.md

@@ -88,6 +88,24 @@ make lint-python-files meinberlin
 
 For details on black see https://github.com/PyCQA/flake8
 
+#### Mypy
+
+We use mypy for static type checking of all our python code. It is
+run as part of the commit hook and checks all staged code. It can also be
+invoked manually as part of the`lint-python-files` command if you want to lint
+a specific file or folder or as part of the `lint` command to lint all files:
+
+```
+# lint all python files
+make lint
+# lint specific python file or folder
+make lint-python-files <path>
+# example for linting all python files for mb
+make lint-python-files meinberlin
+```
+
+For details on black see https://mypy-lang.org/
+
 ### JS / CSS
 
 #### Eslint

requirements/dev.txt

@@ -7,6 +7,7 @@ Faker==23.3.0
 flake8==7.0.0
 freezegun==1.4.0
 isort==5.13.2
+mypy==1.11.0
 psycopg[binary]==3.1.18
 pytest==8.2.1
 pytest-cov==4.1.0