Make Mapping.get(default) more constrained (#14360)

stdlib/collections/__init__.pyi

@@ -108,6 +108,8 @@ class UserDict(MutableMapping[_KT, _VT]):
         @overload
         def get(self, key: _KT, default: None = None) -> _VT | None: ...
         @overload
+        def get(self, key: _KT, default: _VT) -> _VT: ...
+        @overload
         def get(self, key: _KT, default: _T) -> _VT | _T: ...
 
 class UserList(MutableSequence[_T]):
@@ -452,6 +454,8 @@ class ChainMap(MutableMapping[_KT, _VT]):
     @overload
     def get(self, key: _KT, default: None = None) -> _VT | None: ...
     @overload
+    def get(self, key: _KT, default: _VT) -> _VT: ...
+    @overload
     def get(self, key: _KT, default: _T) -> _VT | _T: ...
     def __missing__(self, key: _KT) -> _VT: ...  # undocumented
     def __bool__(self) -> bool: ...

stdlib/importlib/metadata/__init__.pyi

@@ -140,6 +140,8 @@ if sys.version_info >= (3, 10) and sys.version_info < (3, 12):
         @overload
         def get(self, name: _KT, default: None = None) -> _VT | None: ...
         @overload
+        def get(self, name: _KT, default: _VT) -> _VT: ...
+        @overload
         def get(self, name: _KT, default: _T) -> _VT | _T: ...
         def __iter__(self) -> Iterator[_KT]: ...
         def __contains__(self, *args: object) -> bool: ...

stdlib/types.pyi

@@ -323,7 +323,9 @@ class MappingProxyType(Mapping[_KT, _VT_co]):
     @overload
     def get(self, key: _KT, /) -> _VT_co | None: ...
     @overload
-    def get(self, key: _KT, default: _VT_co | _T2, /) -> _VT_co | _T2: ...
+    def get(self, key: _KT, default: _VT_co, /) -> _VT_co: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues] # Covariant type as parameter
+    @overload
+    def get(self, key: _KT, default: _T2, /) -> _VT_co | _T2: ...
     def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
     def __reversed__(self) -> Iterator[_KT]: ...
     def __or__(self, value: Mapping[_T1, _T2], /) -> dict[_KT | _T1, _VT_co | _T2]: ...

stdlib/typing.pyi

@@ -745,7 +745,9 @@ class Mapping(Collection[_KT], Generic[_KT, _VT_co]):
     @overload
     def get(self, key: _KT, /) -> _VT_co | None: ...
     @overload
-    def get(self, key: _KT, /, default: _VT_co | _T) -> _VT_co | _T: ...
+    def get(self, key: _KT, /, default: _VT_co) -> _VT_co: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues] # Covariant type as parameter
+    @overload
+    def get(self, key: _KT, /, default: _T) -> _VT_co | _T: ...
     def items(self) -> ItemsView[_KT, _VT_co]: ...
     def keys(self) -> KeysView[_KT]: ...
     def values(self) -> ValuesView[_VT_co]: ...

stdlib/weakref.pyi

@@ -99,6 +99,8 @@ class WeakValueDictionary(MutableMapping[_KT, _VT]):
     @overload
     def get(self, key: _KT, default: None = None) -> _VT | None: ...
     @overload
+    def get(self, key: _KT, default: _VT) -> _VT: ...
+    @overload
     def get(self, key: _KT, default: _T) -> _VT | _T: ...
     # These are incompatible with Mapping
     def keys(self) -> Iterator[_KT]: ...  # type: ignore[override]
@@ -149,6 +151,8 @@ class WeakKeyDictionary(MutableMapping[_KT, _VT]):
     @overload
     def get(self, key: _KT, default: None = None) -> _VT | None: ...
     @overload
+    def get(self, key: _KT, default: _VT) -> _VT: ...
+    @overload
     def get(self, key: _KT, default: _T) -> _VT | _T: ...
     # These are incompatible with Mapping
     def keys(self) -> Iterator[_KT]: ...  # type: ignore[override]

stubs/WebOb/webob/cookies.pyi

@@ -37,6 +37,8 @@ class RequestCookies(MutableMapping[str, str]):
     @overload
     def get(self, name: str, default: None = None) -> str | None: ...
     @overload
+    def get(self, name: str, default: str) -> str: ...
+    @overload
     def get(self, name: str, default: _T) -> str | _T: ...
     def __delitem__(self, name: str) -> None: ...
     def keys(self) -> KeysView[str]: ...

stubs/WebOb/webob/multidict.pyi

@@ -48,7 +48,9 @@ class MultiDict(MutableMapping[_KT, _VT]):
     def __setitem__(self, key: _KT, value: _VT) -> None: ...
     def add(self, key: _KT, value: _VT) -> None: ...
     @overload
-    def get(self, key: _KT) -> _VT | None: ...
+    def get(self, key: _KT, default: None = None) -> _VT | None: ...
+    @overload
+    def get(self, key: _KT, default: _VT) -> _VT: ...
     @overload
     def get(self, key: _KT, default: _T) -> _VT | _T: ...
     def getall(self, key: _KT) -> list[_VT]: ...

stubs/boltons/boltons/cacheutils.pyi

@@ -26,6 +26,8 @@ class LRI(dict[_KT, _VT]):
     @overload
     def get(self, key: _KT, default: None = None) -> _VT | None: ...
     @overload
+    def get(self, key: _KT, default: _VT) -> _VT: ...
+    @overload
     def get(self, key: _KT, default: _T) -> _T | _VT: ...
     def __delitem__(self, key: _KT) -> None: ...
     @overload

stubs/grpcio/grpc/aio/__init__.pyi

@@ -435,7 +435,9 @@ class Metadata(Mapping[_MetadataKey, _MetadataValue]):
     def delete_all(self, key: _MetadataKey) -> None: ...
     def __iter__(self) -> Iterator[_MetadataKey]: ...
     @overload
-    def get(self, key: _MetadataKey) -> _MetadataValue | None: ...
+    def get(self, key: _MetadataKey, default: None = None) -> _MetadataValue | None: ...
+    @overload
+    def get(self, key: _MetadataKey, default: _MetadataValue) -> _MetadataValue: ...
     @overload
     def get(self, key: _MetadataKey, default: _T) -> _MetadataValue | _T: ...
     def get_all(self, key: _MetadataKey) -> list[_MetadataValue]: ...

stubs/inifile/inifile.pyi

@@ -69,7 +69,9 @@ class IniData(MutableMapping[str, str]):
     def to_dict(self) -> dict[str, str]: ...
     def __len__(self) -> int: ...
     @overload
-    def get(self, name: str) -> str | None: ...
+    def get(self, name: str, default: None = None) -> str | None: ...
+    @overload
+    def get(self, name: str, default: str) -> str: ...
     @overload
     def get(self, name: str, default: _T) -> str | _T: ...
     @overload

stubs/oauthlib/oauthlib/common.pyi

@@ -52,7 +52,10 @@ class CaseInsensitiveDict(dict[str, Incomplete]):
     def __contains__(self, k: object) -> bool: ...
     def __delitem__(self, k: str) -> None: ...
     def __getitem__(self, k: str): ...
-    def get(self, k: str, default=None) -> Incomplete | None: ...
+    @overload
+    def get(self, k: str, default: None = None) -> Incomplete | None: ...
+    @overload
+    def get(self, k: str, default): ...
     def __setitem__(self, k: str, v) -> None: ...
     def update(self, *args, **kwargs) -> None: ...
 

stubs/protobuf/google/protobuf/internal/containers.pyi

@@ -72,7 +72,9 @@ class ScalarMap(MutableMapping[_K, _ScalarV]):
     @overload
     def get(self, key: _K, default: None = None) -> _ScalarV | None: ...
     @overload
-    def get(self, key: _K, default: _ScalarV | _T) -> _ScalarV | _T: ...
+    def get(self, key: _K, default: _ScalarV) -> _ScalarV: ...
+    @overload
+    def get(self, key: _K, default: _T) -> _ScalarV | _T: ...
     def setdefault(self, key: _K, value: _ScalarV | None = None) -> _ScalarV: ...
     def MergeFrom(self, other: Self): ...
     def InvalidateIterators(self) -> None: ...
@@ -95,7 +97,9 @@ class MessageMap(MutableMapping[_K, _MessageV]):
     @overload
     def get(self, key: _K, default: None = None) -> _MessageV | None: ...
     @overload
-    def get(self, key: _K, default: _MessageV | _T) -> _MessageV | _T: ...
+    def get(self, key: _K, default: _MessageV) -> _MessageV: ...
+    @overload
+    def get(self, key: _K, default: _T) -> _MessageV | _T: ...
     def get_or_create(self, key: _K) -> _MessageV: ...
     def setdefault(self, key: _K, value: _MessageV | None = None) -> _MessageV: ...
     def MergeFrom(self, other: Self): ...