[3.13] gh-120221: Support KeyboardInterrupt in asyncio REPL (GH-123795) (#123799)

This switches the main pyrepl event loop to always be non-blocking so that it
can listen to incoming interruptions from other threads.

This also resolves invalid display of exceptions from other threads
(gh-123178).

This also fixes freezes with pasting and an active input hook.
(cherry picked from commit 033510e11d)

Co-authored-by: Łukasz Langa <lukasz@langa.pl>

Lib/_pyrepl/reader.py

@@ -36,8 +36,7 @@ from .trace import trace
 
 # types
 Command = commands.Command
-if False:
-    from .types import Callback, SimpleContextManager, KeySpec, CommandName
+from .types import Callback, SimpleContextManager, KeySpec, CommandName
 
 
 def disp_str(buffer: str) -> tuple[str, list[int]]:
@@ -247,6 +246,7 @@ class Reader:
     lxy: tuple[int, int] = field(init=False)
     scheduled_commands: list[str] = field(default_factory=list)
     can_colorize: bool = False
+    threading_hook: Callback | None = None
 
     ## cached metadata to speed up screen refreshes
     @dataclass
@@ -722,6 +722,24 @@ class Reader:
             self.console.finish()
             self.finish()
 
+    def run_hooks(self) -> None:
+        threading_hook = self.threading_hook
+        if threading_hook is None and 'threading' in sys.modules:
+            from ._threading_handler import install_threading_hook
+            install_threading_hook(self)
+        if threading_hook is not None:
+            try:
+                threading_hook()
+            except Exception:
+                pass
+
+        input_hook = self.console.input_hook
+        if input_hook:
+            try:
+                input_hook()
+            except Exception:
+                pass
+
     def handle1(self, block: bool = True) -> bool:
         """Handle a single event.  Wait as long as it takes if block
         is true (the default), otherwise return False if no event is
@@ -732,16 +750,13 @@ class Reader:
             self.dirty = True
 
         while True:
-            input_hook = self.console.input_hook
-            if input_hook:
-                input_hook()
-                # We use the same timeout as in readline.c: 100ms
-                while not self.console.wait(100):
-                    input_hook()
-                event = self.console.get_event(block=False)
-            else:
-                event = self.console.get_event(block)
-            if not event:  # can only happen if we're not blocking
+            # We use the same timeout as in readline.c: 100ms
+            self.run_hooks()
+            self.console.wait(100)
+            event = self.console.get_event(block=False)
+            if not event:
+                if block:
+                    continue
                 return False
 
             translate = True
@@ -763,8 +778,7 @@ class Reader:
             if cmd is None:
                 if block:
                     continue
-                else:
-                    return False
+                return False
 
             self.do_cmd(cmd)
             return True