bpo-31904: disable os.popen and impacted test cases on VxWorks

Doc/library/os.rst

@@ -32,7 +32,7 @@ Notes on the availability of these functions:
   objects, and result in an object of the same type, if a path or file name is
   returned.
 
-* On VxWorks, os.fork, os.execv and os.spawn*p* are not supported.
+* On VxWorks, os.popen, os.fork, os.execv and os.spawn*p* are not supported.
 
 .. note::
 

Lib/os.py

@@ -36,7 +36,7 @@
 __all__ = ["altsep", "curdir", "pardir", "sep", "pathsep", "linesep",
            "defpath", "name", "path", "devnull", "SEEK_SET", "SEEK_CUR",
            "SEEK_END", "fsencode", "fsdecode", "get_exec_path", "fdopen",
-           "popen", "extsep"]
+           "extsep"]
 
 def _exists(name):
     return name in globals()
@@ -969,51 +969,55 @@ def spawnlpe(mode, file, *args):
 
     __all__.extend(["spawnlp", "spawnlpe"])
 
-
-# Supply os.popen()
-def popen(cmd, mode="r", buffering=-1):
-    if not isinstance(cmd, str):
-        raise TypeError("invalid cmd type (%s, expected string)" % type(cmd))
-    if mode not in ("r", "w"):
-        raise ValueError("invalid mode %r" % mode)
-    if buffering == 0 or buffering is None:
-        raise ValueError("popen() does not support unbuffered streams")
-    import subprocess, io
-    if mode == "r":
-        proc = subprocess.Popen(cmd,
-                                shell=True,
-                                stdout=subprocess.PIPE,
-                                bufsize=buffering)
-        return _wrap_close(io.TextIOWrapper(proc.stdout), proc)
-    else:
-        proc = subprocess.Popen(cmd,
-                                shell=True,
-                                stdin=subprocess.PIPE,
-                                bufsize=buffering)
-        return _wrap_close(io.TextIOWrapper(proc.stdin), proc)
-
-# Helper for popen() -- a proxy for a file whose close waits for the process
-class _wrap_close:
-    def __init__(self, stream, proc):
-        self._stream = stream
-        self._proc = proc
-    def close(self):
-        self._stream.close()
-        returncode = self._proc.wait()
-        if returncode == 0:
-            return None
-        if name == 'nt':
-            return returncode
+# VxWorks has no user space shell provided. As a result, running
+# command in a shell can't be supported.
+if sys.platform != 'vxworks':
+    # Supply os.popen()
+    def popen(cmd, mode="r", buffering=-1):
+        if not isinstance(cmd, str):
+            raise TypeError("invalid cmd type (%s, expected string)" % type(cmd))
+        if mode not in ("r", "w"):
+            raise ValueError("invalid mode %r" % mode)
+        if buffering == 0 or buffering is None:
+            raise ValueError("popen() does not support unbuffered streams")
+        import subprocess, io
+        if mode == "r":
+            proc = subprocess.Popen(cmd,
+                                    shell=True,
+                                    stdout=subprocess.PIPE,
+                                    bufsize=buffering)
+            return _wrap_close(io.TextIOWrapper(proc.stdout), proc)
         else:
-            return returncode << 8  # Shift left to match old behavior
-    def __enter__(self):
-        return self
-    def __exit__(self, *args):
-        self.close()
-    def __getattr__(self, name):
-        return getattr(self._stream, name)
-    def __iter__(self):
-        return iter(self._stream)
+            proc = subprocess.Popen(cmd,
+                                    shell=True,
+                                    stdin=subprocess.PIPE,
+                                    bufsize=buffering)
+            return _wrap_close(io.TextIOWrapper(proc.stdin), proc)
+
+    # Helper for popen() -- a proxy for a file whose close waits for the process
+    class _wrap_close:
+        def __init__(self, stream, proc):
+            self._stream = stream
+            self._proc = proc
+        def close(self):
+            self._stream.close()
+            returncode = self._proc.wait()
+            if returncode == 0:
+                return None
+            if name == 'nt':
+                return returncode
+            else:
+                return returncode << 8  # Shift left to match old behavior
+        def __enter__(self):
+            return self
+        def __exit__(self, *args):
+            self.close()
+        def __getattr__(self, name):
+            return getattr(self._stream, name)
+        def __iter__(self):
+            return iter(self._stream)
+
+    __all__.append("popen")
 
 # Supply os.fdopen()
 def fdopen(fd, *args, **kwargs):

Lib/test/test_os.py

@@ -987,6 +987,7 @@ def _empty_mapping(self):
     # Bug 1110478
     @unittest.skipUnless(unix_shell and os.path.exists(unix_shell),
                          'requires a shell')
+    @unittest.skipUnless(hasattr(os, 'popen'), "needs os.popen()")
     def test_update2(self):
         os.environ.clear()
         os.environ.update(HELLO="World")
@@ -996,6 +997,7 @@ def test_update2(self):
 
     @unittest.skipUnless(unix_shell and os.path.exists(unix_shell),
                          'requires a shell')
+    @unittest.skipUnless(hasattr(os, 'popen'), "needs os.popen()")
     def test_os_popen_iter(self):
         with os.popen("%s -c 'echo \"line1\nline2\nline3\"'"
                       % unix_shell) as popen:

Lib/test/test_popen.py

@@ -7,6 +7,9 @@
 from test import support
 import os, sys
 
+if not hasattr(os, 'popen'):
+    raise unittest.SkipTest("need os.popen()")
+
 # Test that command-lines get down as we expect.
 # To do this we execute:
 #    python -c "import sys;print(sys.argv)" {rest_of_commandline}

Lib/test/test_posix.py

@@ -1040,6 +1040,7 @@ def test_getgrouplist(self):
 
 
     @unittest.skipUnless(hasattr(os, 'getegid'), "test needs os.getegid()")
+    @unittest.skipUnless(hasattr(os, 'popen'), "test needs os.popen()")
     def test_getgroups(self):
         with os.popen('id -G 2>/dev/null') as idg:
             groups = idg.read().strip()
@@ -1929,7 +1930,7 @@ def test_posix_spawnp(self):
 class TestPosixWeaklinking(unittest.TestCase):
     # These test cases verify that weak linking support on macOS works
     # as expected. These cases only test new behaviour introduced by weak linking,
-    # regular behaviour is tested by the normal test cases. 
+    # regular behaviour is tested by the normal test cases.
     #
     # See the section on Weak Linking in Mac/README.txt for more information.
     def setUp(self):

Lib/test/test_select.py

@@ -44,6 +44,7 @@ def test_returned_list_identity(self):
         self.assertIsNot(r, x)
         self.assertIsNot(w, x)
 
+    @unittest.skipUnless(hasattr(os, 'popen'), "need os.popen()")
     def test_select(self):
         cmd = 'for i in 0 1 2 3 4 5 6 7 8 9; do echo testing...; sleep 1; done'
         with os.popen(cmd) as p:

Misc/NEWS.d/next/Tests/2020-07-30-18-06-15.bpo-31904.y3d8dk.rst

@@ -0,0 +1 @@
+Disable os.popen and impacted tests on VxWorks