Address mypy violations on Python 3.8.

syzygy/compat.py

@@ -6,11 +6,13 @@
 field_db_default_supported = django.VERSION >= (5,)
 
 try:
-    from django.db.migrations.autodetector import OperationDependency
+    from django.db.migrations.autodetector import (  # type: ignore[attr-defined]
+        OperationDependency,
+    )
 
 except ImportError:
 
-    class OperationDependency(
+    class OperationDependency(  # type: ignore[no-redef]
         namedtuple("OperationDependency", "app_label model_name field_name type")
     ):
         class Type:

syzygy/conf.py

@@ -14,7 +14,7 @@
 MIGRATION_STAGES_FALLBACK: MigrationStagesSetting
 
 
-def _configure():
+def _configure() -> None:
     global MIGRATION_STAGES_OVERRIDE
     global MIGRATION_STAGES_FALLBACK
     MIGRATION_STAGES_OVERRIDE = getattr(settings, "MIGRATION_STAGES_OVERRIDE", {})

syzygy/management/commands/makemigrations.py

@@ -1,4 +1,4 @@
-from django.core.management.commands import makemigrations  # type: ignore
+from django.core.management.commands import makemigrations
 
 from syzygy.autodetector import MigrationAutodetector
 

syzygy/management/commands/migrate.py

@@ -5,7 +5,7 @@
 
 from django.apps import apps
 from django.core.management import CommandError
-from django.core.management.commands import migrate  # type: ignore
+from django.core.management.commands import migrate
 from django.db import connections
 from django.db.migrations.exceptions import AmbiguityError
 from django.db.migrations.executor import MigrationExecutor

syzygy/operations.py

@@ -127,10 +127,10 @@ def describe(self):
 if field_db_default_supported:
     # XXX: This allows for a more descriptive migration_name_fragment
     # to be associated with instances of AlterField.
-    operations.AlterField.migration_name_fragment = cached_property(
-        operations.AlterField.migration_name_fragment.fget
+    operations.AlterField.migration_name_fragment = cached_property(  # type: ignore[assignment,method-assign]
+        operations.AlterField.migration_name_fragment.fget  # type: ignore[attr-defined]
     )
-    operations.AlterField.migration_name_fragment.name = "migration_name_fragment"
+    operations.AlterField.migration_name_fragment.name = "migration_name_fragment"  # type: ignore[attr-defined]
 
     def get_pre_remove_field_operation(model_name, name, field, **kwargs):
         if field.db_default is not NOT_PROVIDED:
@@ -152,9 +152,9 @@ def get_pre_remove_field_operation(model_name, name, field, **kwargs):
         return operation
 
     # XXX: Shim kept for historical migrations generated before Django 5.
-    PreRemoveField = get_pre_remove_field_operation  # noqa: F811
+    PreRemoveField = get_pre_remove_field_operation  # type: ignore[assignment,misc] # noqa: F811
 else:
-    get_pre_remove_field_operation = PreRemoveField
+    get_pre_remove_field_operation = PreRemoveField  # type: ignore[assignment]
 
 
 class AddField(operations.AddField):
@@ -215,7 +215,7 @@ def get_pre_add_field_operation(model_name, name, field, preserve_default=True):
         return operation
 
     # XXX: Shim kept for historical migrations generated before Django 5.
-    AddField = get_pre_add_field_operation  # noqa: F811
+    AddField = get_pre_add_field_operation  # type: ignore[assignment,misc] # noqa: F811
 else:
     get_pre_add_field_operation = AddField
 
@@ -297,7 +297,7 @@ def get_post_add_field_operation(model_name, name, field, preserve_default=True)
         return operation
 
     # XXX: Shim kept for historical migrations generated before Django 5.
-    PostAddField = get_post_add_field_operation  # noqa: F811
+    PostAddField = get_post_add_field_operation  # type: ignore[assignment,misc] # noqa: F811
 else:
     get_post_add_field_operation = PostAddField
 

syzygy/plan.py

@@ -54,7 +54,7 @@ def partition_operations(
             # If a pre-deploy operation is encountered after a post-deployment
             # one attempt to re-order operation is allowed.
             if all(
-                op.reduce(operation, app_label) is True for op in post_deploy_operations  # type: ignore
+                op.reduce(operation, app_label) is True for op in post_deploy_operations
             ):
                 stage_operations[Stage.PRE_DEPLOY].append(operation)
                 continue
@@ -162,14 +162,16 @@ def get_pre_deploy_plan(plan: Plan) -> Plan:
         if must_post_deploy_migration(migration, backward):
             post_deploy_plan[migration.app_label, migration.name] = migration
         else:
-            post_deploy_dep = post_deploy_plan and next(
-                (
-                    post_deploy_plan[dependency]
-                    for dependency in migration.dependencies
-                    if dependency in post_deploy_plan
-                ),
-                None,
-            )
+            post_deploy_dep = None
+            if post_deploy_plan:
+                post_deploy_dep = next(
+                    (
+                        post_deploy_plan[dependency]
+                        for dependency in migration.dependencies
+                        if dependency in post_deploy_plan
+                    ),
+                    None,
+                )
             if post_deploy_dep:
                 inferred = []
                 stage_defined = _get_defined_stage(migration) is not None

tox.ini

@@ -69,7 +69,7 @@ deps =
 [testenv:mypy]
 usedevelop = false
 basepython = python3.8
-commands = mypy -p syzygy --warn-redundant-casts
+commands = mypy -p syzygy --warn-redundant-casts --warn-unused-ignores
 deps =
     mypy
     django-stubs