Jun 24, 2025 · Jun 24, 2025 · Jun 24, 2025
diff --git a/Lib/asyncio/base_events.py b/Lib/asyncio/base_events.py
                infos = _interleave_addrinfos(infos, interleave)

            exceptions = []
            staggered_exceptions = []
            if happy_eyeballs_delay is None:
                # not using happy eyeballs
                for addrinfo in infos:
                    except OSError:
                        continue
            else:  # using happy eyeballs
                sock = (await staggered.staggered_race(
                sock, _, staggered_exceptions = (await staggered.staggered_race(
                    (
                        # can't use functools.partial as it keeps a reference
                        # to exceptions
                    ),
                    happy_eyeballs_delay,
                    loop=self,
                ))[0]  # can't use sock, _, _ as it keeks a reference to exceptions
                ))

            if sock is None:
                exceptions = [exc for sub in exceptions for exc in sub]
                for exc in staggered_exceptions:
                    if not (isinstance(exc, CancelledError) or exc in exceptions):
                        exceptions.append(exc)
                        del exc

                try:
                    if all_errors:
                        raise ExceptionGroup("create_connection failed", exceptions)
                            ', '.join(str(exc) for exc in exceptions)))
                finally:
                    exceptions = None
                    staggered_exceptions = None

        else:
            if sock is None:
diff --git a/Misc/NEWS.d/next/Library/2025-06-24-06-18-49.gh-issue-135836.7-KHAd.rst b/Misc/NEWS.d/next/Library/2025-06-24-06-18-49.gh-issue-135836.7-KHAd.rst
 Fix :exc:`IndexError` in :meth:`asyncio.loop.create_connection` that could occur when the Happy Eyeballs algorithm resulted in an empty exceptions list during connection attempts, by capturing any exceptions raised by ``staggered_race``
Original file line number	Diff line number	Diff line change
Expand Up		@@ -1131,6 +1131,7 @@ async def create_connection(
		infos = _interleave_addrinfos(infos, interleave)

		exceptions = []
		staggered_exceptions = []
		if happy_eyeballs_delay is None:
		# not using happy eyeballs
		for addrinfo in infos:
Expand All		@@ -1141,7 +1142,7 @@ async def create_connection(
		except OSError:
		continue
		else: # using happy eyeballs
		sock = (await staggered.staggered_race(
		sock, _, staggered_exceptions = (await staggered.staggered_race(
		(
		# can't use functools.partial as it keeps a reference
		# to exceptions
Expand All		@@ -1152,10 +1153,15 @@ async def create_connection(
		),
		happy_eyeballs_delay,
		loop=self,
		))[0] # can't use sock, _, _ as it keeks a reference to exceptions
		))

		if sock is None:
		exceptions = [exc for sub in exceptions for exc in sub]
		for exc in staggered_exceptions:
		if not (isinstance(exc, CancelledError) or exc in exceptions):
		exceptions.append(exc)
		del exc

		try:
		if all_errors:
		raise ExceptionGroup("create_connection failed", exceptions)
Expand All		@@ -1172,6 +1178,7 @@ async def create_connection(
		', '.join(str(exc) for exc in exceptions)))
		finally:
		exceptions = None
		staggered_exceptions = None

		else:
		if sock is None:
Expand Down
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Fix :exc:`IndexError` in :meth:`asyncio.loop.create_connection` that could occur when the Happy Eyeballs algorithm resulted in an empty exceptions list during connection attempts, by capturing any exceptions raised by ``staggered_race``