Add typing to scrapy/utils/deprecate.py.

scrapy/utils/deprecate.py

@@ -2,12 +2,12 @@
 
 import inspect
 import warnings
-from typing import List, Tuple
+from typing import Any, List, Optional, Tuple, Type, overload
 
 from scrapy.exceptions import ScrapyDeprecationWarning
 
 
-def attribute(obj, oldattr, newattr, version="0.12"):
+def attribute(obj: Any, oldattr: str, newattr: str, version: str = "0.12") -> None:
     cname = obj.__class__.__name__
     warnings.warn(
         f"{cname}.{oldattr} attribute is deprecated and will be no longer supported "
@@ -18,16 +18,16 @@ def attribute(obj, oldattr, newattr, version="0.12"):
 
 
 def create_deprecated_class(
-    name,
-    new_class,
-    clsdict=None,
-    warn_category=ScrapyDeprecationWarning,
-    warn_once=True,
-    old_class_path=None,
-    new_class_path=None,
-    subclass_warn_message="{cls} inherits from deprecated class {old}, please inherit from {new}.",
-    instance_warn_message="{cls} is deprecated, instantiate {new} instead.",
-):
+    name: str,
+    new_class: type,
+    clsdict: Optional[dict[str, Any]] = None,
+    warn_category: Type[Warning] = ScrapyDeprecationWarning,
+    warn_once: bool = True,
+    old_class_path: Optional[str] = None,
+    new_class_path: Optional[str] = None,
+    subclass_warn_message: str = "{cls} inherits from deprecated class {old}, please inherit from {new}.",
+    instance_warn_message: str = "{cls} is deprecated, instantiate {new} instead.",
+) -> type:
     """
     Return a "deprecated" class that causes its subclasses to issue a warning.
     Subclasses of ``new_class`` are considered subclasses of this class.
@@ -53,17 +53,20 @@ def create_deprecated_class(
     OldName.
     """
 
-    class DeprecatedClass(new_class.__class__):
-        deprecated_class = None
-        warned_on_subclass = False
+    # https://github.com/python/mypy/issues/4177
+    class DeprecatedClass(new_class.__class__):  # type: ignore[misc, name-defined]
+        deprecated_class: Optional[type] = None
+        warned_on_subclass: bool = False
 
-        def __new__(metacls, name, bases, clsdict_):
+        def __new__(
+            metacls, name: str, bases: Tuple[type, ...], clsdict_: dict[str, Any]
+        ) -> type:
             cls = super().__new__(metacls, name, bases, clsdict_)
             if metacls.deprecated_class is None:
                 metacls.deprecated_class = cls
             return cls
 
-        def __init__(cls, name, bases, clsdict_):
+        def __init__(cls, name: str, bases: Tuple[type, ...], clsdict_: dict[str, Any]):
             meta = cls.__class__
             old = meta.deprecated_class
             if old in bases and not (warn_once and meta.warned_on_subclass):
@@ -81,10 +84,10 @@ def create_deprecated_class(
         # see https://www.python.org/dev/peps/pep-3119/#overloading-isinstance-and-issubclass
         # and https://docs.python.org/reference/datamodel.html#customizing-instance-and-subclass-checks
         # for implementation details
-        def __instancecheck__(cls, inst):
+        def __instancecheck__(cls, inst: Any) -> bool:
             return any(cls.__subclasscheck__(c) for c in (type(inst), inst.__class__))
 
-        def __subclasscheck__(cls, sub):
+        def __subclasscheck__(cls, sub: type) -> bool:
             if cls is not DeprecatedClass.deprecated_class:
                 # we should do the magic only if second `issubclass` argument
                 # is the deprecated class itself - subclasses of the
@@ -98,7 +101,7 @@ def create_deprecated_class(
             mro = getattr(sub, "__mro__", ())
             return any(c in {cls, new_class} for c in mro)
 
-        def __call__(cls, *args, **kwargs):
+        def __call__(cls, *args: Any, **kwargs: Any) -> Any:
             old = DeprecatedClass.deprecated_class
             if cls is old:
                 msg = instance_warn_message.format(
@@ -125,7 +128,7 @@ def create_deprecated_class(
     return deprecated_cls
 
 
-def _clspath(cls, forced=None):
+def _clspath(cls: type, forced: Optional[str] = None) -> str:
     if forced is not None:
         return forced
     return f"{cls.__module__}.{cls.__name__}"
@@ -134,7 +137,17 @@ def _clspath(cls, forced=None):
 DEPRECATION_RULES: List[Tuple[str, str]] = []
 
 
-def update_classpath(path):
+@overload
+def update_classpath(path: str) -> str:
+    ...
+
+
+@overload
+def update_classpath(path: Any) -> Any:
+    ...
+
+
+def update_classpath(path: Any) -> Any:
     """Update a deprecated path from an object with its new location"""
     for prefix, replacement in DEPRECATION_RULES:
         if isinstance(path, str) and path.startswith(prefix):
@@ -147,7 +160,7 @@ def update_classpath(path):
     return path
 
 
-def method_is_overridden(subclass, base_class, method_name):
+def method_is_overridden(subclass: type, base_class: type, method_name: str) -> bool:
     """
     Return True if a method named ``method_name`` of a ``base_class``
     is overridden in a ``subclass``.