gh-149985: Remove future annotations and if TYPE_CHECKING in pyrepl (#149992)

`from __future__ import annotations` is soft-deprecated now that evaluation
of annotations is always deferred. `if TYPE_CHECKING` can often be replaced
with lazy imports.

Author: JelleZijlstra

Lib/_pyrepl/_module_completer.py

@@ -1,5 +1,3 @@
-from __future__ import annotations
-
 import importlib
 import os
 import pkgutil
@@ -15,12 +13,9 @@
 from tokenize import TokenInfo
 from .fancycompleter import safe_getattr
 
-TYPE_CHECKING = False
-
-if TYPE_CHECKING:
-    from types import ModuleType
-    from typing import Any, Iterable, Iterator, Mapping
-    from .types import CompletionAction
+lazy from types import ModuleType
+lazy from typing import Any, Iterable, Iterator, Mapping
+lazy from .types import CompletionAction
 
 
 HARDCODED_SUBMODULES = {

Lib/_pyrepl/_threading_handler.py

@@ -1,30 +1,9 @@
-from __future__ import annotations
-
 from dataclasses import dataclass, field
 import traceback
 
 
-TYPE_CHECKING = False
-if TYPE_CHECKING:
-    from threading import Thread
-    from types import TracebackType
-    from typing import Protocol
-
-    class ExceptHookArgs(Protocol):
-        @property
-        def exc_type(self) -> type[BaseException]: ...
-        @property
-        def exc_value(self) -> BaseException | None: ...
-        @property
-        def exc_traceback(self) -> TracebackType | None: ...
-        @property
-        def thread(self) -> Thread | None: ...
-
-    class ShowExceptions(Protocol):
-        def __call__(self) -> int: ...
-        def add(self, s: str) -> None: ...
-
-    from .reader import Reader
+lazy from threading import ExceptHookArgs
+lazy from .reader import Reader
 
 
 def install_threading_hook(reader: Reader) -> None:

Lib/_pyrepl/base_eventqueue.py

@@ -79,7 +79,7 @@ def push(self, char: int | bytes) -> None:
             if isinstance(k, dict):
                 self.keymap = k
             else:
-                self.insert(Event('key', k, self.buf.take_bytes()))  # type: ignore[attr-defined]
+                self.insert(Event('key', k, self.buf.take_bytes()))
                 self.keymap = self.compiled_keymap
 
         elif self.buf and self.buf[0] == 27:  # escape
@@ -89,7 +89,7 @@ def push(self, char: int | bytes) -> None:
             trace('unrecognized escape sequence, propagating...')
             self.keymap = self.compiled_keymap
             self.insert(Event('key', '\033', b'\033'))
-            for _c in self.buf.take_bytes()[1:]:  # type: ignore[attr-defined]
+            for _c in self.buf.take_bytes()[1:]:
                 self.push(_c)
 
         else:
@@ -98,5 +98,5 @@ def push(self, char: int | bytes) -> None:
             except UnicodeError:
                 return
             else:
-                self.insert(Event('key', decoded, self.buf.take_bytes()))  # type: ignore[attr-defined]
+                self.insert(Event('key', decoded, self.buf.take_bytes()))
             self.keymap = self.compiled_keymap

Lib/_pyrepl/commands.py

@@ -19,10 +19,8 @@
 # CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 # CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
-from __future__ import annotations
 import os
 import time
-from typing import TYPE_CHECKING
 
 # Categories of actions:
 #  killing
@@ -37,8 +35,7 @@
 from .trace import trace
 
 # types
-if TYPE_CHECKING:
-    from .historical_reader import HistoricalReader
+lazy from .historical_reader import HistoricalReader
 
 
 class Command:

Lib/_pyrepl/completing_reader.py

@@ -18,10 +18,7 @@
 # CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 # CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
-from __future__ import annotations
-
 from dataclasses import dataclass, field
-from typing import TYPE_CHECKING
 
 import re
 from . import commands, console, reader
@@ -30,9 +27,7 @@
 
 
 # types
-Command = commands.Command
-if TYPE_CHECKING:
-    from .types import CompletionAction, Keymap
+lazy from .types import CompletionAction, Keymap
 
 
 def prefix(wordlist: list[str], j: int = 0) -> str:
@@ -285,7 +280,7 @@ def collect_keymap(self) -> Keymap:
         return super().collect_keymap() + (
             (r'\t', 'complete'),)
 
-    def after_command(self, cmd: Command) -> None:
+    def after_command(self, cmd: commands.Command) -> None:
         super().after_command(cmd)
         if not isinstance(cmd, (complete, self_insert)):
             self.cmpltn_reset()

Lib/_pyrepl/console.py

@@ -17,8 +17,6 @@
 # CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 # CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
-from __future__ import annotations
-
 import os
 import _colorize
 
@@ -29,15 +27,13 @@
 from dataclasses import dataclass
 import re
 import sys
-from typing import TYPE_CHECKING
 
 from .render import RenderedScreen
 from .trace import trace
 
-if TYPE_CHECKING:
-    from typing import Callable, IO
-
-    from .types import CursorXY
+lazy from collections.abc import Callable
+lazy from typing import IO
+lazy from .types import CursorXY
 
 
 @dataclass

Lib/_pyrepl/content.py

@@ -1,5 +1,3 @@
-from __future__ import annotations
-
 from dataclasses import dataclass
 
 from .utils import ColorSpan, StyleRef, THEME, iter_display_chars, unbracket, wlen

Lib/_pyrepl/fancy_termios.py

@@ -19,13 +19,7 @@
 
 import termios
 
-
-TYPE_CHECKING = False
-
-if TYPE_CHECKING:
-    from typing import cast
-else:
-    cast = lambda typ, val: val
+from typing import cast
 
 
 class TermState:

Lib/_pyrepl/fancycompleter.py

@@ -3,21 +3,16 @@
 #
 #                        All Rights Reserved
 """Colorful tab completion for Python prompt"""
-from __future__ import annotations
-
 from _colorize import ANSIColors, get_colors, get_theme
 import rlcompleter
 import keyword
 import types
 
-TYPE_CHECKING = False
-
-if TYPE_CHECKING:
-    from typing import Any
-    from _colorize import Theme
+lazy from typing import Any
+lazy from _colorize import Theme
 
 
-def safe_getattr(obj, name):
+def safe_getattr(obj: object, name: str) -> object:
     # Mirror rlcompleter's safeguards so completion does not
     # call properties or reify lazy module attributes.
     if isinstance(getattr(type(obj), name, None), property):
@@ -35,7 +30,7 @@ def colorize_matches(names: list[str], values: list[Any], theme: Theme) -> list[
         for name, obj in zip(names, values)
     ]
 
-def _color_for_obj(name: str, value: Any, theme: Theme) -> str:
+def _color_for_obj(name: str, value: object, theme: Theme) -> str:
     t = type(value)
     color = _color_by_type(t, theme)
     return f"{color}{name}{ANSIColors.RESET}"

Lib/_pyrepl/historical_reader.py

@@ -17,17 +17,13 @@
 # CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 # CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
-from __future__ import annotations
-
 from contextlib import contextmanager
 from dataclasses import dataclass, field
 
 from . import commands, input
 from .reader import Reader
 
-
-if False:
-    from .types import SimpleContextManager, KeySpec, CommandName
+lazy from .types import SimpleContextManager, KeySpec, CommandName
 
 
 isearch_keymap: tuple[tuple[KeySpec, CommandName], ...] = tuple(