Improved subprocess handling.

README.rst

@@ -24,7 +24,6 @@ The following standard library modules are available on macOS, but not the other
 Apple platforms:
     * curses
     * posixshmem
-    * posixsubprocess
 
 The binaries support x86_64 and arm64 for macOS; arm64 for iOS and appleTV
 devices; and arm64_32 for watchOS. It also supports device simulators on both

patch/Python/Python.patch

@@ -699,7 +699,7 @@ index 49bcaea78d..891356e54d 100644
                                  + _CASE_INSENSITIVE_PLATFORMS_STR_KEY)
 
 diff --git a/Lib/os.py b/Lib/os.py
-index d26cfc9993..b4db279e00 100644
+index d26cfc9993..ae6629424e 100644
 --- a/Lib/os.py
 +++ b/Lib/os.py
 @@ -36,7 +36,7 @@
@@ -716,7 +716,7 @@ index d26cfc9993..b4db279e00 100644
  del _fscodec
 
 +
-+if sys.platform in ('iOS', 'tvos', 'watchos'):
++if sys.platform in ('ios', 'tvos', 'watchos'):
 +    allows_subprocesses = False
 +else:
 +    allows_subprocesses = True
@@ -834,74 +834,20 @@ index 939893eb5e..8c550ed95a 100644
      return f'{userbase}/lib/python{version[0]}.{version[1]}/site-packages'
 
 diff --git a/Lib/subprocess.py b/Lib/subprocess.py
-index ccb46a6337..6193bcbeaf 100644
+index ccb46a6337..45fefd522d 100644
 --- a/Lib/subprocess.py
 +++ b/Lib/subprocess.py
-@@ -71,9 +71,13 @@
-     _mswindows = True
- except ModuleNotFoundError:
-     _mswindows = False
--    import _posixsubprocess
--    import select
--    import selectors
-+    try:
-+        import _posixsubprocess
-+        import select
-+        import selectors
-+    except ModuleNotFoundError:
-+        # iOS *has* subprocesses, but doesn't support them.
-+        _posixsubprocess = None
- else:
-     from _winapi import (CREATE_NEW_CONSOLE, CREATE_NEW_PROCESS_GROUP,
-                          STD_INPUT_HANDLE, STD_OUTPUT_HANDLE,
-@@ -208,7 +212,7 @@
-             return "%s(%d)" % (self.__class__.__name__, int(self))
-
-         __del__ = Close
--else:
-+elif _posixsubprocess:
-     # When select or poll has indicated that the file is writable,
-     # we can write up to _PIPE_BUF bytes without risk of blocking.
-     # POSIX defines PIPE_BUF as >= 512.
-@@ -236,7 +240,7 @@
-
-     def _cleanup():
-         pass
--else:
-+elif _posixsubprocess:
-     # This lists holds Popen instances for which the underlying process had not
-     # exited at the time its __del__ method got called: those processes are
-     # wait()ed for synchronously from _cleanup() when a new Popen object is
-@@ -255,6 +259,9 @@
-                     # This can happen if two threads create a new Popen instance.
-                     # It's harmless that it was already removed, so ignore.
-                     pass
-+else:
-+    def _cleanup():
-+        pass
-
- PIPE = -1
- STDOUT = -2
-@@ -656,7 +663,7 @@
-     Prefer an implementation which can use vfork() in some cases for best
-     performance.
-     """
--    if _mswindows or not hasattr(os, 'posix_spawn'):
-+    if _mswindows or _posixsubprocess is None or not hasattr(os, 'posix_spawn'):
-         # os.posix_spawn() is not available
-         return False
-
-@@ -759,6 +766,9 @@
+@@ -759,6 +759,9 @@
                   pass_fds=(), *, user=None, group=None, extra_groups=None,
                   encoding=None, errors=None, text=None, umask=-1, pipesize=-1):
          """Create new Popen instance."""
-+        if not _mswindows and _posixsubprocess is None:
++        if not os.allows_subprocesses:
 +            raise RuntimeError(f"Subprocesses are not supported on {sys.platform}")
 +
          _cleanup()
          # Held while anything is calling waitpid before returncode has been
          # updated to prevent clobbering returncode if wait() or poll() are
-@@ -1855,7 +1865,7 @@
+@@ -1855,7 +1858,7 @@
              else:
                  self.returncode = waitstatus_to_exitcode(sts)
 
@@ -910,7 +856,7 @@ index ccb46a6337..6193bcbeaf 100644
                  _WNOHANG=os.WNOHANG, _ECHILD=errno.ECHILD):
              """Check if child process has terminated.  Returns returncode
              attribute.
-@@ -1864,6 +1874,8 @@
+@@ -1864,6 +1867,8 @@
              outside of the local scope (nor can any methods it calls).
 
              """

patch/Python/Setup.embedded

@@ -36,6 +36,7 @@ _multiprocessing _multiprocessing/multiprocessing.c _multiprocessing/semaphore.c
 _opcode _opcode.c
 _operator _operator.c
 _pickle _pickle.c -DPy_BUILD_CORE_MODULE
+_posixsubprocess _posixsubprocess.c
 _queue _queuemodule.c
 _random _randommodule.c -DPy_BUILD_CORE_MODULE
 _sha1 sha1module.c

patch/Python/Setup.macOS

@@ -37,7 +37,6 @@ _decimal _decimal/_decimal.c \
     -DCONFIG_64=1 -DANSI=1 -DHAVE_UINT128_T=1
 
 _posixshmem -I$(srcdir)/Modules/_multiprocessing _multiprocessing/posixshmem.c
-_posixsubprocess _posixsubprocess.c
 
 _scproxy _scproxy.c -framework SystemConfiguration -framework CoreFoundation
 

tests/testbed/src/testbed/app.py

@@ -48,11 +48,11 @@ def main():
                 print(f"{sys_platform}: {test.__name__}", end="...")
             test()
             print(" ok")
-        except Exception as e:
+        except Exception:
             failures += 1
             print(" FAILED!")
             print("-" * 80)
-            traceback.print_exception(e)
+            traceback.print_exc()
             print("-" * 80)
 
     print("=" * 80)