chore: add strict type annotations on the entire codebase

Makefile

@@ -3,6 +3,8 @@
 
 .DEFAULT_GOAL := help
 
+PYTHON_FILES = ./code_annotations/ setup.py tests/ test_utils/
+
 define BROWSER_PYSCRIPT
 import os, webbrowser, sys
 try:
@@ -42,25 +44,28 @@ COMMON_CONSTRAINTS_TXT=requirements/common_constraints.txt
 $(COMMON_CONSTRAINTS_TXT):
 	wget -O "$(@)" https://raw.githubusercontent.com/edx/edx-lint/master/edx_lint/files/common_constraints.txt || touch "$(@)"
 
-upgrade: export CUSTOM_COMPILE_COMMAND=make upgrade
-upgrade: $(COMMON_CONSTRAINTS_TXT) # update the requirements/*.txt files with the latest packages satisfying requirements/*.in
+compile-requirements: export CUSTOM_COMPILE_COMMAND=make upgrade
+compile-requirements: $(COMMON_CONSTRAINTS_TXT) ## Re-compile *.in requirements to *.txt
 	pip install -qr requirements/pip-tools.txt
 	# Make sure to compile files after any other files they include!
-	pip-compile --upgrade --allow-unsafe -o requirements/pip.txt requirements/pip.in
-	pip-compile --upgrade -o requirements/pip-tools.txt requirements/pip-tools.in
+	pip-compile ${COMPILE_OPTS} --allow-unsafe requirements/pip.in
+	pip-compile ${COMPILE_OPTS} requirements/pip-tools.in
 	pip install -qr requirements/pip.txt
 	pip install -qr requirements/pip-tools.txt
-	pip-compile --upgrade -o requirements/base.txt requirements/base.in
-	pip-compile --upgrade -o requirements/django.txt requirements/django.in
-	pip-compile --upgrade -o requirements/test.txt requirements/test.in
-	pip-compile --upgrade -o requirements/doc.txt requirements/doc.in
-	pip-compile --upgrade -o requirements/quality.txt requirements/quality.in
-	pip-compile --upgrade -o requirements/ci.txt requirements/ci.in
-	pip-compile --upgrade -o requirements/dev.txt requirements/dev.in
+	pip-compile ${COMPILE_OPTS} requirements/base.in
+	pip-compile ${COMPILE_OPTS} requirements/django.in
+	pip-compile ${COMPILE_OPTS} requirements/test.in
+	pip-compile ${COMPILE_OPTS} requirements/doc.in
+	pip-compile ${COMPILE_OPTS} requirements/quality.in
+	pip-compile ${COMPILE_OPTS} requirements/ci.in
+	pip-compile ${COMPILE_OPTS} requirements/dev.in
 	# Let tox control the Django version for tests
 	sed '/^[dD]jango==/d' requirements/test.txt > requirements/test.tmp
 	mv requirements/test.tmp requirements/test.txt
 
+upgrade: $(COMMON_CONSTRAINTS_TXT) ## update the requirements/*.txt files with the latest packages satisfying requirements/*.in
+	$(MAKE) compile-requirements COMPILE_OPTS="--upgrade"
+
 quality: ## check coding style with pycodestyle and pylint
 	tox -e quality
 
@@ -70,9 +75,28 @@ requirements: ## install development environment requirements
 	pip-sync requirements/dev.txt requirements/test.txt requirements/private.*
 	pip install -e .
 
-test: clean ## run tests in the current virtualenv
+test: clean test-unit  test-quality ## run tests in the current virtualenv
+
+test-unit:  ## run unit tests
 	pytest
 
+test-quality: test-lint test-types test-codestyle test-docstyle test-isort selfcheck  ## run all quality tests
+
+test-codestyle:  ## run pycodestyle tests
+	pycodestyle ${PYTHON_FILES}
+
+test-docstyle: ## run pydocstyle tests
+	pydocstyle ${PYTHON_FILES}
+
+test-isort: ## run isort tests
+	isort --check-only --diff ${PYTHON_FILES}
+
+test-lint: ## run pylint tests
+	pylint ${PYTHON_FILES}
+
+test-types: ## run mypy tests on the whole codebase
+	mypy --ignore-missing-imports --strict ${PYTHON_FILES}
+
 diff_cover: test ## find diff lines that need test coverage
 	diff-cover coverage.xml
 

code_annotations/annotation_errors.py

@@ -3,20 +3,20 @@
 """
 from collections import namedtuple
 
-AnnotationErrorType = namedtuple(
+AnnotationError = namedtuple(
     "AnnotationError", ["message", "symbol", "description"]
 )
 
-# The TYPES list should contain all AnnotationErrorType instances. This list can then be parsed by others, for instance
+# The TYPES list should contain all AnnotationError instances. This list can then be parsed by others, for instance
 # to expose errors to pylint.
-TYPES = []
+TYPES: list[AnnotationError] = []
 
 
-def add_error_type(message, symbol, description):
+def add_error_type(message: str, symbol: str, description: str) -> AnnotationError:
     """
-    Create an AnnotationErrorType instance and add it to TYPES.
+    Create an AnnotationError instance and add it to TYPES.
     """
-    error_type = AnnotationErrorType(
+    error_type = AnnotationError(
         message,
         symbol,
         description,
@@ -32,32 +32,32 @@ def add_error_type(message, symbol, description):
 # It is important to preserve the insertion order of these error types in the TYPES list, as edx-lint uses the error
 # type indices to generate numerical pylint IDs. If the insertion order is changed, the pylint IDs will change too,
 # which might cause incompatibilities down the road. Thus, new items should be added at the end.
-InvalidChoice = add_error_type(
+InvalidChoice: AnnotationError = add_error_type(
     '"%s" is not a valid choice for "%s". Expected one of %s.',
     "annotation-invalid-choice",
     "Emitted when the value of a choice field is not one of the valid choices",
 )
-DuplicateChoiceValue = add_error_type(
+DuplicateChoiceValue: AnnotationError = add_error_type(
     '"%s" is already present in this annotation.',
     "annotation-duplicate-choice-value",
     "Emitted when duplicate values are found in a choice field",
 )
-MissingChoiceValue = add_error_type(
+MissingChoiceValue: AnnotationError = add_error_type(
     'no value found for "%s". Expected one of %s.',
     "annotation-missing-choice-value",
     "Emitted when a choice field does not have any value",
 )
-InvalidToken = add_error_type(
+InvalidToken: AnnotationError = add_error_type(
     "'%s' token does not belong to group '%s'. Expected one of: %s",
     "annotation-invalid-token",
     "Emitted when a token is found in a group for which it is not valid",
 )
-DuplicateToken = add_error_type(
+DuplicateToken: AnnotationError = add_error_type(
     "found duplicate token '%s'",
     "annotation-duplicate-token",
     "Emitted when a token is found twice in a group",
 )
-MissingToken = add_error_type(
+MissingToken: AnnotationError = add_error_type(
     "missing non-optional annotation: '%s'",
     "annotation-missing-token",
     "Emitted when a required token is missing from a group",