bpo-46364: Use sockets for stdin of asyncio only on AIX (GH-30596)

Signed-off-by: Christoph Hamsen <hamsen.christoph@posteo.de>
Co-authored-by: July Tikhonov <july.tikh@gmail.com>
(cherry picked from commit c9ed0327a9c741a1808926b409df29467baf303a)

Co-authored-by: Christoph Hamsen <37963496+xopham@users.noreply.github.com>

1 files changed, 3 insertions, 4 deletions

diff --git a/Lib/asyncio/unix_events.py b/Lib/asyncio/unix_events.py
index 96e6d73..0495f33 100644
--- a/Lib/asyncio/unix_events.py
+++ b/Lib/asyncio/unix_events.py
@@ -800,12 +800,11 @@ class _UnixSubprocessTransport(base_subprocess.BaseSubprocessTransport):
 
     def _start(self, args, shell, stdin, stdout, stderr, bufsize, **kwargs):
         stdin_w = None
-        if stdin == subprocess.PIPE:
-            # Use a socket pair for stdin, since not all platforms
+        if stdin == subprocess.PIPE and sys.platform.startswith('aix'):
+            # Use a socket pair for stdin on AIX, since it does not
             # support selecting read events on the write end of a
             # socket (which we use in order to detect closing of the
-            # other end).  Notably this is needed on AIX, and works
-            # just fine on other platforms.
+            # other end).
             stdin, stdin_w = socket.socketpair()
         try:
             self._proc = subprocess.Popen(