python · srittau · May 26, 2025 · May 26, 2025 · Jun 2, 2025 · Jun 2, 2025
diff --git a/stdlib/_csv.pyi b/stdlib/_csv.pyi
@@ -1,9 +1,8 @@
 import csv
 import sys
-from _typeshed import SupportsWrite
 from collections.abc import Iterable
 from typing import Any, Final, Literal, type_check_only
-from typing_extensions import Self, TypeAlias
+from typing_extensions import Self, TypeAlias, Writer as _Writer
 
 __version__: Final[str]
 
@@ -89,7 +88,7 @@ else:
         def writerows(self, rows: Iterable[Iterable[Any]]) -> None: ...
 
 def writer(
-    csvfile: SupportsWrite[str],
+    csvfile: _Writer[str],
     dialect: _DialectLike = "excel",
     *,
     delimiter: str = ",",

diff --git a/stdlib/_curses.pyi b/stdlib/_curses.pyi
@@ -1,8 +1,8 @@
 import sys
-from _typeshed import ReadOnlyBuffer, SupportsRead, SupportsWrite
+from _typeshed import ReadOnlyBuffer
 from curses import _ncurses_version
 from typing import Any, final, overload
-from typing_extensions import TypeAlias
+from typing_extensions import Reader, TypeAlias, Writer
 
 # NOTE: This module is ordinarily only available on Unix, but the windows-curses
 # package makes it available on Windows as well with the same contents.
@@ -297,7 +297,7 @@ def get_escdelay() -> int: ...
 def get_tabsize() -> int: ...
 def getmouse() -> tuple[int, int, int, int, int]: ...
 def getsyx() -> tuple[int, int]: ...
-def getwin(file: SupportsRead[bytes], /) -> window: ...
+def getwin(file: Reader[bytes], /) -> window: ...
 def halfdelay(tenths: int, /) -> None: ...
 def has_colors() -> bool: ...
 
@@ -515,7 +515,7 @@ class window:  # undocumented
     def overwrite(
         self, destwin: window, sminrow: int, smincol: int, dminrow: int, dmincol: int, dmaxrow: int, dmaxcol: int
     ) -> None: ...
-    def putwin(self, file: SupportsWrite[bytes], /) -> None: ...
+    def putwin(self, file: Writer[bytes], /) -> None: ...
     def redrawln(self, beg: int, num: int, /) -> None: ...
     def redrawwin(self) -> None: ...
     @overload

diff --git a/stdlib/_pickle.pyi b/stdlib/_pickle.pyi
@@ -1,8 +1,8 @@
-from _typeshed import ReadableBuffer, SupportsWrite
+from _typeshed import ReadableBuffer
 from collections.abc import Callable, Iterable, Iterator, Mapping
 from pickle import PickleBuffer as PickleBuffer
 from typing import Any, Protocol, type_check_only
-from typing_extensions import TypeAlias
+from typing_extensions import TypeAlias, Writer
 
 class _ReadableFileobj(Protocol):
     def read(self, n: int, /) -> bytes: ...
@@ -20,7 +20,7 @@ _ReducedType: TypeAlias = (
 
 def dump(
     obj: Any,
-    file: SupportsWrite[bytes],
+    file: Writer[bytes],
     protocol: int | None = None,
     *,
     fix_imports: bool = True,
@@ -62,11 +62,7 @@ class Pickler:
     reducer_override: Callable[[Any], Any]
     bin: bool  # undocumented
     def __init__(
-        self,
-        file: SupportsWrite[bytes],
-        protocol: int | None = None,
-        fix_imports: bool = True,
-        buffer_callback: _BufferCallback = None,
+        self, file: Writer[bytes], protocol: int | None = None, fix_imports: bool = True, buffer_callback: _BufferCallback = None
     ) -> None: ...
     @property
     def memo(self) -> PicklerMemoProxy: ...

diff --git a/stdlib/_typeshed/__init__.pyi b/stdlib/_typeshed/__init__.pyi
@@ -22,7 +22,7 @@ from typing import (
     final,
     overload,
 )
-from typing_extensions import Buffer, LiteralString, Self as _Self, TypeAlias
+from typing_extensions import Buffer, LiteralString, Self as _Self, TypeAlias, deprecated
 
 _KT = TypeVar("_KT")
 _KT_co = TypeVar("_KT_co", covariant=True)
@@ -253,7 +253,7 @@ FileDescriptor: TypeAlias = int  # stable
 FileDescriptorLike: TypeAlias = int | HasFileno  # stable
 FileDescriptorOrPath: TypeAlias = int | StrOrBytesPath
 
-# stable
+@deprecated("Use typing_extensions.Reader instead. Will be removed in December 2025 or later.")
 class SupportsRead(Protocol[_T_co]):
     def read(self, length: int = ..., /) -> _T_co: ...
 
@@ -265,7 +265,7 @@ class SupportsReadline(Protocol[_T_co]):
 class SupportsNoArgReadline(Protocol[_T_co]):
     def readline(self) -> _T_co: ...
 
-# stable
+@deprecated("Use typing_extensions.Writer instead. Will be removed in December 2025 or later.")
 class SupportsWrite(Protocol[_T_contra]):
     def write(self, s: _T_contra, /) -> object: ...
 

diff --git a/stdlib/abc.pyi b/stdlib/abc.pyi
@@ -1,9 +1,8 @@
 import _typeshed
 import sys
-from _typeshed import SupportsWrite
 from collections.abc import Callable
 from typing import Any, Literal, TypeVar
-from typing_extensions import Concatenate, ParamSpec, deprecated
+from typing_extensions import Concatenate, ParamSpec, Writer, deprecated
 
 _T = TypeVar("_T")
 _R_co = TypeVar("_R_co", covariant=True)
@@ -24,7 +23,7 @@ class ABCMeta(type):
 
     def __instancecheck__(cls: ABCMeta, instance: Any) -> bool: ...
     def __subclasscheck__(cls: ABCMeta, subclass: type) -> bool: ...
-    def _dump_registry(cls: ABCMeta, file: SupportsWrite[str] | None = None) -> None: ...
+    def _dump_registry(cls: ABCMeta, file: Writer[str] | None = None) -> None: ...
     def register(cls: ABCMeta, subclass: type[_T]) -> type[_T]: ...
 
 def abstractmethod(funcobj: _FuncT) -> _FuncT: ...

diff --git a/stdlib/argparse.pyi b/stdlib/argparse.pyi
@@ -1,9 +1,9 @@
 import sys
-from _typeshed import SupportsWrite, sentinel
+from _typeshed import sentinel
 from collections.abc import Callable, Generator, Iterable, Sequence
 from re import Pattern
 from typing import IO, Any, ClassVar, Final, Generic, NoReturn, Protocol, TypeVar, overload
-from typing_extensions import Self, TypeAlias, deprecated
+from typing_extensions import Self, TypeAlias, Writer, deprecated
 
 __all__ = [
     "ArgumentParser",
@@ -208,8 +208,8 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer):
         help: str | None = None,
         metavar: str | None = None,
     ) -> _SubParsersAction[_ArgumentParserT]: ...
-    def print_usage(self, file: SupportsWrite[str] | None = None) -> None: ...
-    def print_help(self, file: SupportsWrite[str] | None = None) -> None: ...
+    def print_usage(self, file: Writer[str] | None = None) -> None: ...
+    def print_help(self, file: Writer[str] | None = None) -> None: ...
     def format_usage(self) -> str: ...
     def format_help(self) -> str: ...
     @overload
@@ -255,7 +255,7 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer):
     def _get_value(self, action: Action, arg_string: str) -> Any: ...
     def _check_value(self, action: Action, value: Any) -> None: ...
     def _get_formatter(self) -> HelpFormatter: ...
-    def _print_message(self, message: str, file: SupportsWrite[str] | None = None) -> None: ...
+    def _print_message(self, message: str, file: Writer[str] | None = None) -> None: ...
 
 class HelpFormatter:
     # undocumented

diff --git a/stdlib/array.pyi b/stdlib/array.pyi
@@ -1,9 +1,9 @@
 import sys
-from _typeshed import ReadableBuffer, SupportsRead, SupportsWrite
+from _typeshed import ReadableBuffer
 from collections.abc import Iterable, MutableSequence
 from types import GenericAlias
 from typing import Any, ClassVar, Literal, SupportsIndex, TypeVar, overload
-from typing_extensions import Self, TypeAlias
+from typing_extensions import Reader, Self, TypeAlias, Writer
 
 _IntTypeCode: TypeAlias = Literal["b", "B", "h", "H", "i", "I", "l", "L", "q", "Q"]
 _FloatTypeCode: TypeAlias = Literal["f", "d"]
@@ -41,7 +41,7 @@ class array(MutableSequence[_T]):
     def count(self, v: _T, /) -> int: ...
     def extend(self, bb: Iterable[_T], /) -> None: ...
     def frombytes(self, buffer: ReadableBuffer, /) -> None: ...
-    def fromfile(self, f: SupportsRead[bytes], n: int, /) -> None: ...
+    def fromfile(self, f: Reader[bytes], n: int, /) -> None: ...
     def fromlist(self, list: list[_T], /) -> None: ...
     def fromunicode(self, ustr: str, /) -> None: ...
     if sys.version_info >= (3, 10):
@@ -53,7 +53,7 @@ class array(MutableSequence[_T]):
     def pop(self, i: int = -1, /) -> _T: ...
     def remove(self, v: _T, /) -> None: ...
     def tobytes(self) -> bytes: ...
-    def tofile(self, f: SupportsWrite[bytes], /) -> None: ...
+    def tofile(self, f: Writer[bytes], /) -> None: ...
     def tolist(self) -> list[_T]: ...
     def tounicode(self) -> str: ...
 

diff --git a/stdlib/asyncio/graph.pyi b/stdlib/asyncio/graph.pyi
@@ -1,8 +1,8 @@
-from _typeshed import SupportsWrite
 from asyncio import Future
 from dataclasses import dataclass
 from types import FrameType
 from typing import Any, overload
+from typing_extensions import Writer
 
 __all__ = ("capture_call_graph", "format_call_graph", "print_call_graph", "FrameCallGraphEntry", "FutureCallGraph")
 
@@ -22,5 +22,5 @@ def capture_call_graph(future: None = None, /, *, depth: int = 1, limit: int | N
 def capture_call_graph(future: Future[Any], /, *, depth: int = 1, limit: int | None = None) -> FutureCallGraph | None: ...
 def format_call_graph(future: Future[Any] | None = None, /, *, depth: int = 1, limit: int | None = None) -> str: ...
 def print_call_graph(
-    future: Future[Any] | None = None, /, *, file: SupportsWrite[str] | None = None, depth: int = 1, limit: int | None = None
+    future: Future[Any] | None = None, /, *, file: Writer[str] | None = None, depth: int = 1, limit: int | None = None
 ) -> None: ...
diff --git a/stdlib/builtins.pyi b/stdlib/builtins.pyi
@@ -28,7 +28,6 @@ from _typeshed import (
     SupportsRDivMod,
     SupportsRichComparison,
     SupportsRichComparisonT,
-    SupportsWrite,
 )
 from collections.abc import Awaitable, Callable, Iterable, Iterator, MutableSet, Reversible, Set as AbstractSet, Sized
 from io import BufferedRandom, BufferedReader, BufferedWriter, FileIO, TextIOWrapper
@@ -70,6 +69,7 @@ from typing_extensions import (  # noqa: Y023
     TypeGuard,
     TypeIs,
     TypeVarTuple,
+    Writer,
     deprecated,
 )
 
@@ -1768,15 +1768,11 @@ def open(
 ) -> IO[Any]: ...
 def ord(c: str | bytes | bytearray, /) -> int: ...
 
-class _SupportsWriteAndFlush(SupportsWrite[_T_contra], SupportsFlush, Protocol[_T_contra]): ...
+class _SupportsWriteAndFlush(Writer[_T_contra], SupportsFlush, Protocol[_T_contra]): ...
 
 @overload
 def print(
-    *values: object,
-    sep: str | None = " ",
-    end: str | None = "\n",
-    file: SupportsWrite[str] | None = None,
-    flush: Literal[False] = False,
+    *values: object, sep: str | None = " ", end: str | None = "\n", file: Writer[str] | None = None, flush: Literal[False] = False
 ) -> None: ...
 @overload
 def print(

diff --git a/stdlib/configparser.pyi b/stdlib/configparser.pyi
@@ -1,9 +1,9 @@
 import sys
-from _typeshed import MaybeNone, StrOrBytesPath, SupportsWrite
+from _typeshed import MaybeNone, StrOrBytesPath
 from collections.abc import Callable, ItemsView, Iterable, Iterator, Mapping, MutableMapping, Sequence
 from re import Pattern
 from typing import Any, ClassVar, Final, Literal, TypeVar, overload
-from typing_extensions import TypeAlias
+from typing_extensions import TypeAlias, Writer
 
 if sys.version_info >= (3, 14):
     __all__ = (
@@ -312,7 +312,7 @@ class RawConfigParser(_Parser):
     @overload
     def items(self, section: _SectionName, raw: bool = False, vars: _Section | None = None) -> list[tuple[str, str]]: ...
     def set(self, section: _SectionName, option: str, value: str | None = None) -> None: ...
-    def write(self, fp: SupportsWrite[str], space_around_delimiters: bool = True) -> None: ...
+    def write(self, fp: Writer[str], space_around_delimiters: bool = True) -> None: ...
     def remove_option(self, section: _SectionName, option: str) -> bool: ...
     def remove_section(self, section: _SectionName) -> bool: ...
     def optionxform(self, optionstr: str) -> str: ...

diff --git a/stdlib/csv.pyi b/stdlib/csv.pyi
@@ -24,11 +24,10 @@ if sys.version_info >= (3, 10):
 else:
     from _csv import _reader as Reader, _writer as Writer
 
-from _typeshed import SupportsWrite
 from collections.abc import Collection, Iterable, Mapping, Sequence
 from types import GenericAlias
 from typing import Any, Generic, Literal, TypeVar, overload
-from typing_extensions import Self
+from typing_extensions import Self, Writer as _Writer
 
 __all__ = [
     "QUOTE_MINIMAL",
@@ -128,7 +127,7 @@ class DictWriter(Generic[_T]):
     writer: Writer
     def __init__(
         self,
-        f: SupportsWrite[str],
+        f: _Writer[str],
         fieldnames: Collection[_T],
         restval: Any | None = "",
         extrasaction: Literal["raise", "ignore"] = "raise",

diff --git a/stdlib/distutils/dist.pyi b/stdlib/distutils/dist.pyi
@@ -1,4 +1,4 @@
-from _typeshed import Incomplete, StrOrBytesPath, StrPath, SupportsWrite
+from _typeshed import Incomplete, StrOrBytesPath, StrPath
 from collections.abc import Iterable, MutableMapping
 from distutils.cmd import Command
 from distutils.command.bdist import bdist
@@ -23,7 +23,7 @@ from distutils.command.sdist import sdist
 from distutils.command.upload import upload
 from re import Pattern
 from typing import IO, ClassVar, Literal, TypeVar, overload
-from typing_extensions import TypeAlias
+from typing_extensions import TypeAlias, Writer
 
 command_re: Pattern[str]
 
@@ -51,7 +51,7 @@ class DistributionMetadata:
     obsoletes: list[str] | None
     def read_pkg_file(self, file: IO[str]) -> None: ...
     def write_pkg_info(self, base_dir: StrPath) -> None: ...
-    def write_pkg_file(self, file: SupportsWrite[str]) -> None: ...
+    def write_pkg_file(self, file: Writer[str]) -> None: ...
     def get_name(self) -> str: ...
     def get_version(self) -> str: ...
     def get_fullname(self) -> str: ...

diff --git a/stdlib/email/generator.pyi b/stdlib/email/generator.pyi
@@ -1,8 +1,7 @@
-from _typeshed import SupportsWrite
 from email.message import Message
 from email.policy import Policy
 from typing import Any, Generic, TypeVar, overload
-from typing_extensions import Self
+from typing_extensions import Self, Writer
 
 __all__ = ["Generator", "DecodedGenerator", "BytesGenerator"]
 
@@ -15,30 +14,25 @@ class Generator(Generic[_MessageT]):
     @overload
     def __init__(
         self: Generator[Any],  # The Policy of the message is used.
-        outfp: SupportsWrite[str],
+        outfp: Writer[str],
         mangle_from_: bool | None = None,
         maxheaderlen: int | None = None,
         *,
         policy: None = None,
     ) -> None: ...
     @overload
     def __init__(
-        self,
-        outfp: SupportsWrite[str],
-        mangle_from_: bool | None = None,
-        maxheaderlen: int | None = None,
-        *,
-        policy: Policy[_MessageT],
+        self, outfp: Writer[str], mangle_from_: bool | None = None, maxheaderlen: int | None = None, *, policy: Policy[_MessageT]
     ) -> None: ...
     def write(self, s: str) -> None: ...
     def flatten(self, msg: _MessageT, unixfrom: bool = False, linesep: str | None = None) -> None: ...
-    def clone(self, fp: SupportsWrite[str]) -> Self: ...
+    def clone(self, fp: Writer[str]) -> Self: ...
 
 class BytesGenerator(Generator[_MessageT]):
     @overload
     def __init__(
         self: BytesGenerator[Any],  # The Policy of the message is used.
-        outfp: SupportsWrite[bytes],
+        outfp: Writer[bytes],
         mangle_from_: bool | None = None,
         maxheaderlen: int | None = None,
         *,
@@ -47,7 +41,7 @@ class BytesGenerator(Generator[_MessageT]):
     @overload
     def __init__(
         self,
-        outfp: SupportsWrite[bytes],
+        outfp: Writer[bytes],
         mangle_from_: bool | None = None,
         maxheaderlen: int | None = None,
         *,
@@ -58,7 +52,7 @@ class DecodedGenerator(Generator[_MessageT]):
     @overload
     def __init__(
         self: DecodedGenerator[Any],  # The Policy of the message is used.
-        outfp: SupportsWrite[str],
+        outfp: Writer[str],
         mangle_from_: bool | None = None,
         maxheaderlen: int | None = None,
         fmt: str | None = None,
@@ -68,7 +62,7 @@ class DecodedGenerator(Generator[_MessageT]):
     @overload
     def __init__(
         self,
-        outfp: SupportsWrite[str],
+        outfp: Writer[str],
         mangle_from_: bool | None = None,
         maxheaderlen: int | None = None,
         fmt: str | None = None,

diff --git a/stdlib/email/iterators.pyi b/stdlib/email/iterators.pyi
@@ -1,6 +1,6 @@
-from _typeshed import SupportsWrite
 from collections.abc import Iterator
 from email.message import Message
+from typing_extensions import Writer
 
 __all__ = ["body_line_iterator", "typed_subpart_iterator", "walk"]
 
@@ -9,4 +9,4 @@ def typed_subpart_iterator(msg: Message, maintype: str = "text", subtype: str |
 def walk(self: Message) -> Iterator[Message]: ...
 
 # We include the seemingly private function because it is documented in the stdlib documentation.
-def _structure(msg: Message, fp: SupportsWrite[str] | None = None, level: int = 0, include_default: bool = False) -> None: ...
+def _structure(msg: Message, fp: Writer[str] | None = None, level: int = 0, include_default: bool = False) -> None: ...