build: add import linter check (openedx#31062)

* build: add import linter check

.github/workflows/lint-imports.yml

@@ -0,0 +1,48 @@
+name: Lint Python Imports
+
+on: pull_request
+
+jobs:
+
+  lint-imports:
+    name: Lint Python Imports
+    runs-on: ubuntu-20.04
+
+    steps:
+      - name: Check out branch
+        uses: actions/checkout@v2
+
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: '3.8'
+
+      - name: Install system requirements
+        run: sudo apt update && sudo apt install -y libxmlsec1-dev
+
+      - name: Install pip
+        run: python -m pip install -r requirements/pip.txt
+
+      - name: Get pip cache dir
+        id: pip-cache-dir
+        run: echo "::set-output name=dir::$(pip cache dir)"
+
+      - name: Cache pip dependencies
+        id: cache-dependencies
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.pip-cache-dir.outputs.dir }}
+          key: ${{ runner.os }}-pip-${{ hashFiles('requirements/edx/development.txt') }}
+          restore-keys: ${{ runner.os }}-pip-
+
+      - name: Install python dependencies
+        run: pip install -r requirements/edx/development.txt
+
+      # As long there are sub-projects[1] in edx-platform, we analyze each
+      # project separately here, in order to make import-linting errors easier
+      # to pinpoint.
+      #
+      #  [1] https://openedx.atlassian.net/browse/BOM-2579
+
+      - name: Analyze imports (repo root)
+        run: make lint-imports

Makefile

@@ -175,6 +175,9 @@ docker_push: docker_tag docker_auth ## push to docker hub
 	docker push "openedx/cms-dev:latest"
 	docker push "openedx/cms-dev:${GITHUB_SHA}"
 
+lint-imports:
+	lint-imports
+
 # WARNING (EXPERIMENTAL):
 # This installs the Ubuntu requirements necessary to make `pip install` and some other basic
 # dev commands to pass. This is not necessarily everything needed to get a working edx-platform.

requirements/edx/development.txt

@@ -173,6 +173,7 @@ click==8.1.3
     #   code-annotations
     #   edx-django-utils
     #   edx-lint
+    #   import-linter
     #   nltk
     #   pact-python
     #   pip-tools
@@ -750,6 +751,10 @@ geoip2==4.6.0
     # via -r requirements/edx/testing.txt
 glob2==0.7
     # via -r requirements/edx/testing.txt
+grimp==1.3
+    # via
+    #   -r requirements/edx/testing.txt
+    #   import-linter
 gunicorn==20.1.0
     # via -r requirements/edx/testing.txt
 h11==0.14.0
@@ -776,6 +781,8 @@ idna==3.4
     #   yarl
 imagesize==1.4.1
     # via sphinx
+import-linter==1.3.0
+    # via -r requirements/edx/testing.txt
 importlib-metadata==5.0.0
     # via
     #   -r requirements/edx/testing.txt
@@ -1577,6 +1584,7 @@ typing-extensions==4.4.0
     #   -r requirements/edx/testing.txt
     #   astroid
     #   django-countries
+    #   import-linter
     #   mypy
     #   pydantic
     #   pylint

requirements/edx/testing.in

@@ -28,6 +28,7 @@ factory-boy               # Library for creating test fixtures, used in many tes
 # Pinning the freezegun version because 0.3.13 is causing failures which have also been reported on the git repo by public.
 freezegun                 # Allows tests to mock the output of assorted datetime module functions
 httpretty                 # Library for mocking HTTP requests, used in many tests
+import-linter             # Tool for making assertions about which modules can import which others
 isort                     # For checking and fixing the order of imports
 pycodestyle               # Checker for compliance with the Python style guide (PEP 8)
 polib                     # Library for manipulating gettext translation files, used to test paver i18n commands

requirements/edx/testing.txt

@@ -163,6 +163,7 @@ click==8.1.3
     #   code-annotations
     #   edx-django-utils
     #   edx-lint
+    #   import-linter
     #   nltk
     #   pact-python
     #   user-util
@@ -720,6 +721,8 @@ geoip2==4.6.0
     # via -r requirements/edx/base.txt
 glob2==0.7
     # via -r requirements/edx/base.txt
+grimp==1.3
+    # via import-linter
 gunicorn==20.1.0
     # via -r requirements/edx/base.txt
 h11==0.14.0
@@ -742,6 +745,8 @@ idna==3.4
     #   requests
     #   snowflake-connector-python
     #   yarl
+import-linter==1.3.0
+    # via -r requirements/edx/testing.in
 importlib-metadata==5.0.0
     # via
     #   -r requirements/edx/base.txt
@@ -1464,6 +1469,7 @@ typing-extensions==4.4.0
     #   -r requirements/edx/base.txt
     #   astroid
     #   django-countries
+    #   import-linter
     #   pydantic
     #   pylint
     #   snowflake-connector-python

setup.cfg

@@ -47,3 +47,29 @@ multi_line_output=3
 skip=
     envs
     migrations
+
+[importlinter]
+root_packages =
+    lms
+    cms
+include_external_packages = True
+
+[importlinter:contract:1]
+name = lms and cms are independent
+type = independence
+modules =
+    lms
+    cms
+ignore_imports =
+    # lms side imports that we are ignoring for now
+    lms.djangoapps.course_home_api.outline.tests.test_view -> cms.djangoapps.contentstore.outlines
+    lms.djangoapps.courseware.plugins -> cms.djangoapps.contentstore.utils
+    lms.djangoapps.course_home_api.tests.utils -> cms.djangoapps.contentstore.outlines
+    # cms side imports that we are ignoring for now
+    cms.djangoapps.contentstore.views.tests.test_item -> lms.djangoapps.lms_xblock.mixin
+    cms.envs.common -> lms.envs.common
+    cms.djangoapps.contentstore.signals.handlers -> lms.djangoapps.grades.api
+    cms.djangoapps.contentstore.course_group_config -> lms.lib.utils
+    cms.djangoapps.contentstore.views.preview -> lms.djangoapps.lms_xblock.field_data
+    cms.envs.common -> lms.djangoapps.lms_xblock.mixin
+    cms.envs.test -> lms.envs.test