gh-85984: Utilize new "winsize" functions from termios in pty tests. (#101831)

Utilize new functions termios.tcgetwinsize() and termios.tcsetwinsize in test_pty.py.

Signed-off-by: Soumendra Ganguly <soumendraganguly@gmail.com>
Co-authored-by: Gregory P. Smith <greg@krypto.org>

1 files changed, 27 insertions, 69 deletions

diff --git a/Lib/test/test_pty.py b/Lib/test/test_pty.py
index fa0dbcc..c723bb3 100644
--- a/Lib/test/test_pty.py
+++ b/Lib/test/test_pty.py
@@ -3,6 +3,8 @@ from test.support.import_helper import import_module
 
 # Skip these tests if termios or fcntl are not available
 import_module('termios')
+# fcntl is a proxy for not being one of the wasm32 platforms even though we
+# don't use this module... a proper check for what crashes those is needed.
 import_module("fcntl")
 
 import errno
@@ -15,20 +17,12 @@ import signal
 import socket
 import io # readline
 import unittest
-
-import struct
-import fcntl
 import warnings
 
 TEST_STRING_1 = b"I wish to buy a fish license.\n"
 TEST_STRING_2 = b"For my pet fish, Eric.\n"
 
-try:
-    _TIOCGWINSZ = tty.TIOCGWINSZ
-    _TIOCSWINSZ = tty.TIOCSWINSZ
-    _HAVE_WINSZ = True
-except AttributeError:
-    _HAVE_WINSZ = False
+_HAVE_WINSZ = hasattr(tty, "TIOCGWINSZ") and hasattr(tty, "TIOCSWINSZ")
 
 if verbose:
     def debug(msg):
@@ -82,14 +76,6 @@ def expectedFailureIfStdinIsTTY(fun):
         pass
     return fun
 
-def _get_term_winsz(fd):
-    s = struct.pack("HHHH", 0, 0, 0, 0)
-    return fcntl.ioctl(fd, _TIOCGWINSZ, s)
-
-def _set_term_winsz(fd, winsz):
-    fcntl.ioctl(fd, _TIOCSWINSZ, winsz)
-
-
 # Marginal testing of pty suite. Cannot do extensive 'do or fail' testing
 # because pty code is not too portable.
 class PtyTest(unittest.TestCase):
@@ -105,18 +91,14 @@ class PtyTest(unittest.TestCase):
         self.addCleanup(signal.alarm, 0)
         signal.alarm(10)
 
-        # Save original stdin window size
-        self.stdin_rows = None
-        self.stdin_cols = None
+        # Save original stdin window size.
+        self.stdin_dim = None
         if _HAVE_WINSZ:
             try:
-                stdin_dim = os.get_terminal_size(pty.STDIN_FILENO)
-                self.stdin_rows = stdin_dim.lines
-                self.stdin_cols = stdin_dim.columns
-                old_stdin_winsz = struct.pack("HHHH", self.stdin_rows,
-                                              self.stdin_cols, 0, 0)
-                self.addCleanup(_set_term_winsz, pty.STDIN_FILENO, old_stdin_winsz)
-            except OSError:
+                self.stdin_dim = tty.tcgetwinsize(pty.STDIN_FILENO)
+                self.addCleanup(tty.tcsetwinsize, pty.STDIN_FILENO,
+                                self.stdin_dim)
+            except tty.error:
                 pass
 
     def handle_sig(self, sig, frame):
@@ -131,41 +113,40 @@ class PtyTest(unittest.TestCase):
         try:
             mode = tty.tcgetattr(pty.STDIN_FILENO)
         except tty.error:
-            # not a tty or bad/closed fd
+            # Not a tty or bad/closed fd.
             debug("tty.tcgetattr(pty.STDIN_FILENO) failed")
             mode = None
 
-        new_stdin_winsz = None
-        if self.stdin_rows is not None and self.stdin_cols is not None:
+        new_dim = None
+        if self.stdin_dim:
             try:
                 # Modify pty.STDIN_FILENO window size; we need to
                 # check if pty.openpty() is able to set pty slave
                 # window size accordingly.
-                debug("Setting pty.STDIN_FILENO window size")
-                debug(f"original size: (rows={self.stdin_rows}, cols={self.stdin_cols})")
-                target_stdin_rows = self.stdin_rows + 1
-                target_stdin_cols = self.stdin_cols + 1
-                debug(f"target size: (rows={target_stdin_rows}, cols={target_stdin_cols})")
-                target_stdin_winsz = struct.pack("HHHH", target_stdin_rows,
-                                                 target_stdin_cols, 0, 0)
-                _set_term_winsz(pty.STDIN_FILENO, target_stdin_winsz)
+                debug("Setting pty.STDIN_FILENO window size.")
+                debug(f"original size: (row, col) = {self.stdin_dim}")
+                target_dim = (self.stdin_dim[0] + 1, self.stdin_dim[1] + 1)
+                debug(f"target size: (row, col) = {target_dim}")
+                tty.tcsetwinsize(pty.STDIN_FILENO, target_dim)
 
                 # Were we able to set the window size
                 # of pty.STDIN_FILENO successfully?
-                new_stdin_winsz = _get_term_winsz(pty.STDIN_FILENO)
-                self.assertEqual(new_stdin_winsz, target_stdin_winsz,
+                new_dim = tty.tcgetwinsize(pty.STDIN_FILENO)
+                self.assertEqual(new_dim, target_dim,
                                  "pty.STDIN_FILENO window size unchanged")
             except OSError:
-                warnings.warn("Failed to set pty.STDIN_FILENO window size")
+                warnings.warn("Failed to set pty.STDIN_FILENO window size.")
                 pass
 
         try:
             debug("Calling pty.openpty()")
             try:
-                master_fd, slave_fd = pty.openpty(mode, new_stdin_winsz)
+                master_fd, slave_fd, slave_name = pty.openpty(mode, new_dim,
+                                                              True)
             except TypeError:
                 master_fd, slave_fd = pty.openpty()
-            debug(f"Got master_fd '{master_fd}', slave_fd '{slave_fd}'")
+                slave_name = None
+            debug(f"Got {master_fd=}, {slave_fd=}, {slave_name=}")
         except OSError:
             # " An optional feature could not be imported " ... ?
             raise unittest.SkipTest("Pseudo-terminals (seemingly) not functional.")
@@ -181,8 +162,8 @@ class PtyTest(unittest.TestCase):
         if mode:
             self.assertEqual(tty.tcgetattr(slave_fd), mode,
                              "openpty() failed to set slave termios")
-        if new_stdin_winsz:
-            self.assertEqual(_get_term_winsz(slave_fd), new_stdin_winsz,
+        if new_dim:
+            self.assertEqual(tty.tcgetwinsize(slave_fd), new_dim,
                              "openpty() failed to set slave window size")
 
         # Ensure the fd is non-blocking in case there's nothing to read.
@@ -367,9 +348,8 @@ class SmallPtyTests(unittest.TestCase):
         self.files.extend(socketpair)
         return socketpair
 
-    def _mock_select(self, rfds, wfds, xfds, timeout=0):
+    def _mock_select(self, rfds, wfds, xfds):
         # This will raise IndexError when no more expected calls exist.
-        # This ignores the timeout
         self.assertEqual(self.select_rfds_lengths.pop(0), len(rfds))
         return self.select_rfds_results.pop(0), [], []
 
@@ -409,28 +389,6 @@ class SmallPtyTests(unittest.TestCase):
         self.assertEqual(os.read(read_from_stdout_fd, 20), b'from master')
         self.assertEqual(os.read(masters[1], 20), b'from stdin')
 
-    def test__copy_eof_on_all(self):
-        """Test the empty read EOF case on both master_fd and stdin."""
-        read_from_stdout_fd, mock_stdout_fd = self._pipe()
-        pty.STDOUT_FILENO = mock_stdout_fd
-        mock_stdin_fd, write_to_stdin_fd = self._pipe()
-        pty.STDIN_FILENO = mock_stdin_fd
-        socketpair = self._socketpair()
-        masters = [s.fileno() for s in socketpair]
-
-        socketpair[1].close()
-        os.close(write_to_stdin_fd)
-
-        pty.select = self._mock_select
-        self.select_rfds_lengths.append(2)
-        self.select_rfds_results.append([mock_stdin_fd, masters[0]])
-        # We expect that both fds were removed from the fds list as they
-        # both encountered an EOF before the second select call.
-        self.select_rfds_lengths.append(0)
-
-        # We expect the function to return without error.
-        self.assertEqual(pty._copy(masters[0]), None)
-
     def test__restore_tty_mode_normal_return(self):
         """Test that spawn resets the tty mode no when _copy returns normally."""