PEP 702 (@deprecated): descriptors

Author: tyralla

mypy/checker.py

@@ -4425,7 +4425,7 @@ def check_member_assignment(
             msg=self.msg,
             chk=self,
         )
-        get_type = analyze_descriptor_access(attribute_type, mx)
+        get_type = analyze_descriptor_access(attribute_type, mx, assignment=True)
         if not attribute_type.type.has_readable_member("__set__"):
             # If there is no __set__, we type-check that the assigned value matches
             # the return type of __get__. This doesn't match the python semantics,
@@ -4492,6 +4492,12 @@ def check_member_assignment(
             callable_name=callable_name,
         )
 
+        # Search for possible deprecations:
+        mx.chk.check_deprecated(dunder_set, mx.context)
+        mx.chk.warn_deprecated_overload_item(
+            dunder_set, mx.context, inferred_dunder_set_type, attribute_type
+        )
+
         # In the following cases, a message already will have been recorded in check_call.
         if (not isinstance(inferred_dunder_set_type, CallableType)) or (
             len(inferred_dunder_set_type.arg_types) < 2
@@ -7688,6 +7694,22 @@ def warn_deprecated(self, node: SymbolNode | None, context: Context) -> None:
             warn = self.msg.fail if self.options.report_deprecated_as_error else self.msg.note
             warn(deprecated, context, code=codes.DEPRECATED)
 
+    def warn_deprecated_overload_item(
+        self, node: SymbolNode | None,
+        context: Context,
+        target: CallableType,
+        instance: Instance | None = None,
+    ) -> None:
+        """Warn if the overload item corresponding to the given callable is deprecated."""
+        if isinstance(node, OverloadedFuncDef):
+            for item in node.items:
+                if isinstance(item, Decorator):
+                    candidate = item.func.type
+                    if instance is not None:
+                        candidate = bind_self(candidate, instance)
+                    if candidate == target:
+                        self.warn_deprecated(item.func, context)
+
 
 class CollectArgTypeVarTypes(TypeTraverserVisitor):
     """Collects the non-nested argument types in a set."""

mypy/checkexpr.py

@@ -1482,10 +1482,8 @@ def check_call_expr_with_callee_type(
             object_type=object_type,
         )
         proper_callee = get_proper_type(callee_type)
-        if isinstance(e.callee, NameExpr) and isinstance(e.callee.node, OverloadedFuncDef):
-            for item in e.callee.node.items:
-                if isinstance(item, Decorator) and (item.func.type == callee_type):
-                    self.chk.check_deprecated(item.func, e)
+        if isinstance(e.callee, NameExpr):
+            self.chk.warn_deprecated_overload_item(e.callee.node, e, callee_type)
         if isinstance(e.callee, RefExpr) and isinstance(proper_callee, CallableType):
             # Cache it for find_isinstance_check()
             if proper_callee.type_guard is not None:

mypy/checkmember.py

@@ -638,7 +638,9 @@ def check_final_member(name: str, info: TypeInfo, msg: MessageBuilder, ctx: Cont
             msg.cant_assign_to_final(name, attr_assign=True, ctx=ctx)
 
 
-def analyze_descriptor_access(descriptor_type: Type, mx: MemberContext) -> Type:
+def analyze_descriptor_access(
+    descriptor_type: Type, mx: MemberContext, *, assignment: bool = False
+) -> Type:
     """Type check descriptor access.
 
     Arguments:
@@ -719,6 +721,12 @@ def analyze_descriptor_access(descriptor_type: Type, mx: MemberContext) -> Type:
         callable_name=callable_name,
     )
 
+    if not assignment:
+        mx.chk.check_deprecated(dunder_get, mx.context)
+        mx.chk.warn_deprecated_overload_item(
+            dunder_get, mx.context, inferred_dunder_get_type, descriptor_type
+        )
+
     inferred_dunder_get_type = get_proper_type(inferred_dunder_get_type)
     if isinstance(inferred_dunder_get_type, AnyType):
         # check_call failed, and will have reported an error

test-data/unit/check-deprecated.test

@@ -490,6 +490,59 @@ C().g = "x"  # N: function __main__.C.g is deprecated: use g2 instead \
 [builtins fixtures/property.pyi]
 
 
+[case testDeprecatedDescriptor]
+
+from typing import Optional, Type, Union
+from typing_extensions import deprecated, overload
+
+@deprecated("use E1 instead")
+class D1:
+    def __get__(self, obj: Optional[C], objtype: Type[C]) -> Union[D1, int]: ...
+
+class D2:
+    @deprecated("use E2.__get__ instead")
+    def __get__(self, obj: Optional[C], objtype: Type[C]) -> Union[D2, int]: ...
+
+    @deprecated("use E2.__set__ instead")
+    def __set__(self, obj: C, value: int) -> None: ...
+
+class D3:
+    @overload
+    @deprecated("use E3.__get__ instead")
+    def __get__(self, obj: None, objtype: Type[C]) -> D3: ...
+    @overload
+    @deprecated("use E3.__get__ instead")
+    def __get__(self, obj: C, objtype: Type[C]) -> int: ...
+    def __get__(self, obj: Optional[C], objtype: Type[C]) -> Union[D3, int]: ...
+
+    @overload
+    def __set__(self, obj: C, value: int) -> None: ...
+    @overload
+    @deprecated("use E3.__set__ instead")
+    def __set__(self, obj: C, value: str) -> None: ...
+    def __set__(self, obj: C, value: Union[int, str]) -> None: ...
+
+class C:
+    d1 = D1() # N: class __main__.D1 is deprecated: use E1 instead
+    d2 = D2()
+    d3 = D3()
+
+c: C
+C.d1
+c.d1
+c.d1 = 1
+
+C.d2  # N: function __main__.D2.__get__ is deprecated: use E2.__get__ instead
+c.d2  # N: function __main__.D2.__get__ is deprecated: use E2.__get__ instead
+c.d2 = 1  # N: function __main__.D2.__set__ is deprecated: use E2.__set__ instead
+
+C.d3  # N: overload def (self: __main__.D3, obj: None, objtype: type[__main__.C]) -> __main__.D3 of function __main__.D3.__get__ is deprecated: use E3.__get__ instead
+c.d3  # N: overload def (self: __main__.D3, obj: __main__.C, objtype: type[__main__.C]) -> builtins.int of function __main__.D3.__get__ is deprecated: use E3.__get__ instead
+c.d3 = 1
+c.d3 = "x"  # N: overload def (self: __main__.D3, obj: __main__.C, value: builtins.str) of function __main__.D3.__set__ is deprecated: use E3.__set__ instead
+[builtins fixtures/property.pyi]
+
+
 [case testDeprecatedOverloadedFunction]
 
 from typing import Union