Merge 4b069ac into ff0668f

.gitignore

@@ -4,3 +4,4 @@ dist/
 *.egg-info/*
 .coverage
 .tox
+.mypy_cache/

.travis.yml

@@ -14,6 +14,7 @@ jobs:
   include:
     - { stage: lint, env: TOXENV=flake8, python: 3.6 }
     - { stage: lint, env: TOXENV=isort, python: 3.6 }
+    - { stage: lint, env: TOXENV=mypy, python: 3.6 }
     - stage: deploy
       if: tag IS present
       python: 3.6

setup.cfg

@@ -11,5 +11,11 @@ branch = 1
 [flake8]
 max-line-length = 119
 
+[mypy]
+plugins = mypy_django_plugin.main
+
+[mypy.plugins.django-stubs]
+django_settings_module = "tests.settings"
+
 [wheel]
-universal = 1
+universal = 1

syzygy/management/commands/migrate.py

@@ -1,5 +1,7 @@
 from django.core.management import CommandError
-from django.core.management.commands.migrate import Command as MigrateCommand
+from django.core.management.commands.migrate import (  # type: ignore
+    Command as MigrateCommand,
+)
 from django.db.models.signals import pre_migrate
 
 from syzygy.plan import get_prerequisite_plan

syzygy/plan.py

@@ -1,10 +1,10 @@
-from typing import List, NewType, Optional, Tuple
+from typing import List, Optional, Tuple
 
 from django.conf import settings
 from django.db.migrations import DeleteModel, Migration, RemoveField
 from django.db.migrations.operations.base import Operation
 
-Plan = NewType("Plan", List[Tuple[Migration, bool]])
+Plan = List[Tuple[Migration, bool]]
 
 
 def must_postpone_operation(
@@ -63,7 +63,7 @@ def get_prerequisite_plan(plan: Plan) -> Plan:
     If the plan contains non-contiguous sequence of prerequisite migrations
     or migrations with ambiguous prerequisite nature a `ValueError` is raised.
     """
-    prerequisite_plan = []
+    prerequisite_plan: Plan = []
     postpone = False
     for migration, backward in plan:
         if must_postpone_migration(migration, backward):

tests/settings.py

@@ -1,7 +1,11 @@
+from typing import Dict, Tuple
+
 SECRET_KEY = "not-secret-anymore"
 
 TIME_ZONE = "America/Montreal"
 
 DATABASES = {"default": {"ENGINE": "django.db.backends.sqlite3"}}
 
 INSTALLED_APPS = ["syzygy", "tests"]
+
+SYZYGY_POSTPONE: Dict[Tuple[str, str], bool] = {}

tox.ini

@@ -41,3 +41,12 @@ commands = isort --recursive --check-only --diff syzygy tests
 deps =
     isort
     Django>=2.2,<3
+
+[testenv:mypy]
+usedevelop = false
+basepython = python3.6
+commands = mypy -p syzygy --warn-redundant-casts
+deps =
+    mypy
+    django-stubs
+    Django>=2.2,<3