--- cpython/Lib/pty.py	2020-08-17 19:38:35.113811651 -0500
+++ pty.py	2020-08-17 19:43:13.021171983 -0500
@@ -148,6 +148,22 @@
             else:
                 _writen(master_fd, data)
 
+def _setwinsz(master_fd):
+    """Sets window size."""
+    try:
+        from struct import pack, error as StructError
+        from fcntl import ioctl
+        from termios import TIOCGWINSZ, TIOCSWINSZ
+    except ImportError:
+        pass
+    else:
+        try:
+            w = pack('HHHH', 0, 0, 0, 0)
+            s = ioctl(STDIN_FILENO, TIOCGWINSZ, w)
+            ioctl(master_fd, TIOCSWINSZ, s)
+        except (struct.error, OSError):
+            pass
+
 def spawn(argv, master_read=_read, stdin_read=_read):
     """Create a spawned process."""
     if type(argv) == type(''):
@@ -162,6 +178,7 @@
         restore = 1
     except tty.error:    # This is the same as termios.error
         restore = 0
+    _setwinsz(master_fd)
     try:
         _copy(master_fd, master_read, stdin_read)
     except OSError: