Use report_config_data mypy plugin hook to reset cache on changes (#1578)

Author: sobolevn

mypy_django_plugin/config.py

@@ -112,3 +112,10 @@ def parse_ini_file(self, filepath: Path) -> None:
             self.strict_settings = parser.getboolean(section, "strict_settings", fallback=True)
         except ValueError:
             exit_with_error(INVALID_BOOL_SETTING.format(key="strict_settings"))
+
+    def to_json(self) -> Dict[str, Any]:
+        """We use this method to reset mypy cache via `report_config_data` hook."""
+        return {
+            "django_settings_module": self.django_settings_module,
+            "strict_settings": self.strict_settings,
+        }

mypy_django_plugin/main.py

@@ -1,7 +1,7 @@
 import itertools
 import sys
 from functools import partial
-from typing import Callable, Dict, List, Optional, Tuple, Type
+from typing import Any, Callable, Dict, List, Optional, Tuple, Type
 
 from mypy.modulefinder import mypy_path
 from mypy.nodes import MypyFile, TypeInfo
@@ -14,6 +14,7 @@
     FunctionContext,
     MethodContext,
     Plugin,
+    ReportConfigContext,
 )
 from mypy.types import Type as MypyType
 
@@ -331,6 +332,10 @@ def get_dynamic_class_hook(self, fullname: str) -> Optional[Callable[[DynamicCla
                 return create_new_manager_class_from_as_manager_method
         return None
 
+    def report_config_data(self, ctx: ReportConfigContext) -> Dict[str, Any]:
+        # Cache would be cleared if any settings do change.
+        return self.plugin_config.to_json()
+
 
 def plugin(version: str) -> Type[NewSemanalDjangoPlugin]:
     return NewSemanalDjangoPlugin