From 7b907281ea1a90391e52b391f336fac33fd042cf Mon Sep 17 00:00:00 2001
From: Bo Bayles <bbayles@gmail.com>
Date: Thu, 11 Jan 2018 08:21:06 -0600
Subject: [PATCH 01/12] bpo-32146: freeze_support can apply to non-Windows
 platforms also

---
 Doc/library/multiprocessing.rst | 11 +++++------
 Lib/multiprocessing/context.py  |  2 +-
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst
index 8b3081cb80c972..701f75279d838d 100644
--- a/Doc/library/multiprocessing.rst
+++ b/Doc/library/multiprocessing.rst
@@ -926,8 +926,8 @@ Miscellaneous
 .. function:: freeze_support()
 
    Add support for when a program which uses :mod:`multiprocessing` has been
-   frozen to produce a Windows executable.  (Has been tested with **py2exe**,
-   **PyInstaller** and **cx_Freeze**.)
+   frozen to produce an application executable.  (Has been tested with
+   **py2exe**, **PyInstaller** and **cx_Freeze**.)
 
    One needs to call this function straight after the ``if __name__ ==
    '__main__'`` line of the main module.  For example::
@@ -944,10 +944,9 @@ Miscellaneous
    If the ``freeze_support()`` line is omitted then trying to run the frozen
    executable will raise :exc:`RuntimeError`.
 
-   Calling ``freeze_support()`` has no effect when invoked on any operating
-   system other than Windows.  In addition, if the module is being run
-   normally by the Python interpreter on Windows (the program has not been
-   frozen), then ``freeze_support()`` has no effect.
+   ``freeze_support()`` has no effect when invoked in a module that is being
+   run normally by the Python interpreter (i.e., instead of by a frozen
+   executable).
 
 .. function:: get_all_start_methods()
 
diff --git a/Lib/multiprocessing/context.py b/Lib/multiprocessing/context.py
index c98ee434249037..909f3d529d2143 100644
--- a/Lib/multiprocessing/context.py
+++ b/Lib/multiprocessing/context.py
@@ -144,7 +144,7 @@ def freeze_support(self):
         '''Check whether this is a fake forked process in a frozen executable.
         If so then run code specified by commandline and exit.
         '''
-        if sys.platform == 'win32' and getattr(sys, 'frozen', False):
+        if getattr(sys, 'frozen', False):
             from .spawn import freeze_support
             freeze_support()
 

From b0d30bc48c1447356031742b44d95eaa1db17af3 Mon Sep 17 00:00:00 2001
From: Bo Bayles <bbayles@gmail.com>
Date: Fri, 12 Jan 2018 21:05:09 -0600
Subject: [PATCH 02/12] bpo-32146: Provisional fix for non-Windows executables
 (spawn)

---
 Lib/multiprocessing/spawn.py | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Lib/multiprocessing/spawn.py b/Lib/multiprocessing/spawn.py
index 1f4f3f496f51a2..c1c63ca90bd17b 100644
--- a/Lib/multiprocessing/spawn.py
+++ b/Lib/multiprocessing/spawn.py
@@ -73,6 +73,17 @@ def freeze_support():
                 kwds[name] = int(value)
         spawn_main(**kwds)
         sys.exit()
+    # fix the command line for the semaphore tracker (unix)
+    elif (
+        (len(sys.argv) >= 3) and
+        (sys.argv[-2] == '-c') and
+        ('semaphore_tracker import main;' in sys.argv[-1])
+    ):
+        r = int(sys.argv[-1].rsplit('(')[1].split(')')[0])
+        from multiprocessing.semaphore_tracker import main;
+        main(r)
+        sys.exit()
+    # TODO: fix the command line for the fork server (unix)
 
 
 def get_command_line(**kwds):

From 8baf4e4fc686c8e35d4e702bb78812453fe35077 Mon Sep 17 00:00:00 2001
From: Bo Bayles <bbayles@gmail.com>
Date: Sun, 14 Jan 2018 08:19:54 -0600
Subject: [PATCH 03/12] bpo-32146: Provisional fix for non-Windows executables
 (forkserver)

---
 Lib/multiprocessing/spawn.py | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/Lib/multiprocessing/spawn.py b/Lib/multiprocessing/spawn.py
index c1c63ca90bd17b..11b1651b9dc862 100644
--- a/Lib/multiprocessing/spawn.py
+++ b/Lib/multiprocessing/spawn.py
@@ -8,6 +8,7 @@
 # Licensed to PSF under a Contributor Agreement.
 #
 
+import ast
 import os
 import sys
 import runpy
@@ -83,7 +84,22 @@ def freeze_support():
         from multiprocessing.semaphore_tracker import main;
         main(r)
         sys.exit()
-    # TODO: fix the command line for the fork server (unix)
+    # fix the command line for the fork server (unix)
+    elif (
+        (len(sys.argv) >= 3) and
+        (sys.argv[-2] == '-c') and
+        ('forkserver import main;' in sys.argv[-1])
+    ):
+        cmd = sys.argv[-1]
+        main_args = cmd.split('main(')[1].rsplit(')', 1)[0].split(', ', 3)
+        listener_fd = int(main_args[0])
+        alive_r = int(main_args[1])
+        preload = ast.literal_eval(main_args[2])
+        kwds = ast.literal_eval(main_args[3][2:])
+
+        from multiprocessing.forkserver import main
+        main(listener_fd, alive_r, preload, **kwds)
+        sys.exit()
 
 
 def get_command_line(**kwds):

From 64456d9f7be5b0824bea9d7f36fe359042c733ac Mon Sep 17 00:00:00 2001
From: Bo Bayles <bbayles@gmail.com>
Date: Sun, 14 Jan 2018 08:42:07 -0600
Subject: [PATCH 04/12] bpo-32146: Move commandline checks to separate
 functions

---
 Lib/multiprocessing/spawn.py | 36 ++++++++++++++++++++++++++----------
 1 file changed, 26 insertions(+), 10 deletions(-)

diff --git a/Lib/multiprocessing/spawn.py b/Lib/multiprocessing/spawn.py
index 11b1651b9dc862..4c41f8663d88aa 100644
--- a/Lib/multiprocessing/spawn.py
+++ b/Lib/multiprocessing/spawn.py
@@ -60,6 +60,28 @@ def is_forking(argv):
         return False
 
 
+def is_semaphore_tracker(argv):
+    '''
+    Return whether commandline indicates we are running the semaphore tracker
+    '''
+    return (
+        (len(argv) >= 3) and
+        (argv[-2] == '-c') and
+        ('semaphore_tracker import main;' in sys.argv[-1])
+    )
+
+
+def is_forkserver(argv):
+    '''
+    Return whether commandline indicates we are running the forkserver
+    '''
+    return (
+        (len(sys.argv) >= 3) and
+        (sys.argv[-2] == '-c') and
+        ('forkserver import main;' in sys.argv[-1])
+    )
+
+
 def freeze_support():
     '''
     Run code for process object if this in not the main process
@@ -75,21 +97,15 @@ def freeze_support():
         spawn_main(**kwds)
         sys.exit()
     # fix the command line for the semaphore tracker (unix)
-    elif (
-        (len(sys.argv) >= 3) and
-        (sys.argv[-2] == '-c') and
-        ('semaphore_tracker import main;' in sys.argv[-1])
-    ):
+    # we extract the single argument to the semaphore tracker's main()
+    elif is_semaphore_tracker(sys.argv):
         r = int(sys.argv[-1].rsplit('(')[1].split(')')[0])
         from multiprocessing.semaphore_tracker import main;
         main(r)
         sys.exit()
     # fix the command line for the fork server (unix)
-    elif (
-        (len(sys.argv) >= 3) and
-        (sys.argv[-2] == '-c') and
-        ('forkserver import main;' in sys.argv[-1])
-    ):
+    # we extract the 3 args and keywords to the forkserver's main()
+    elif is_forkserver(sys.argv):
         cmd = sys.argv[-1]
         main_args = cmd.split('main(')[1].rsplit(')', 1)[0].split(', ', 3)
         listener_fd = int(main_args[0])

From 748c2f1cc56c235b2ac0ee68286b87a3aa5abd9d Mon Sep 17 00:00:00 2001
From: Bo Bayles <bbayles@gmail.com>
Date: Sun, 14 Jan 2018 17:13:19 -0600
Subject: [PATCH 05/12] bpo-32146: Add Misc/NEWS entry for freeze_support
 enhancements

---
 .../next/Library/2018-01-14-16-34-26.bpo-32146.6pFDbn.rst       | 2 ++
 1 file changed, 2 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Library/2018-01-14-16-34-26.bpo-32146.6pFDbn.rst

diff --git a/Misc/NEWS.d/next/Library/2018-01-14-16-34-26.bpo-32146.6pFDbn.rst b/Misc/NEWS.d/next/Library/2018-01-14-16-34-26.bpo-32146.6pFDbn.rst
new file mode 100644
index 00000000000000..5c5636bf41ffe4
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-01-14-16-34-26.bpo-32146.6pFDbn.rst
@@ -0,0 +1,2 @@
+``multiprocessing.freeze_support`` now works on non-Windows platforms as
+well.

From 3a0964ae759f181371d4520e0984cda71beea05c Mon Sep 17 00:00:00 2001
From: Bo Bayles <bbayles@gmail.com>
Date: Sun, 14 Jan 2018 17:25:41 -0600
Subject: [PATCH 06/12] bpo-32146: Use dummy --multiprocessing- command line
 arguments

---
 Lib/multiprocessing/forkserver.py        |  3 ++-
 Lib/multiprocessing/semaphore_tracker.py |  3 ++-
 Lib/multiprocessing/spawn.py             | 23 ++++++++++-------------
 3 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/Lib/multiprocessing/forkserver.py b/Lib/multiprocessing/forkserver.py
index 040b46e66a0330..10342533a4a8b0 100644
--- a/Lib/multiprocessing/forkserver.py
+++ b/Lib/multiprocessing/forkserver.py
@@ -127,7 +127,8 @@ def ensure_running(self):
                     cmd %= (listener.fileno(), alive_r, self._preload_modules,
                             data)
                     exe = spawn.get_executable()
-                    args = [exe] + util._args_from_interpreter_flags()
+                    args = [exe, '--multiprocessing-forkserver']
+                    args += util._args_from_interpreter_flags()
                     args += ['-c', cmd]
                     pid = util.spawnv_passfds(exe, args, fds_to_pass)
                 except:
diff --git a/Lib/multiprocessing/semaphore_tracker.py b/Lib/multiprocessing/semaphore_tracker.py
index 3e31bf8402ee2d..0d909b3963163a 100644
--- a/Lib/multiprocessing/semaphore_tracker.py
+++ b/Lib/multiprocessing/semaphore_tracker.py
@@ -66,7 +66,8 @@ def ensure_running(self):
                 fds_to_pass.append(r)
                 # process will out live us, so no need to wait on pid
                 exe = spawn.get_executable()
-                args = [exe] + util._args_from_interpreter_flags()
+                args = [exe, '--multiprocessing-semaphore-tracker']
+                args += util._args_from_interpreter_flags()
                 args += ['-c', cmd % r]
                 pid = util.spawnv_passfds(exe, args, fds_to_pass)
             except:
diff --git a/Lib/multiprocessing/spawn.py b/Lib/multiprocessing/spawn.py
index 4c41f8663d88aa..f850dcca5d2cc6 100644
--- a/Lib/multiprocessing/spawn.py
+++ b/Lib/multiprocessing/spawn.py
@@ -64,22 +64,20 @@ def is_semaphore_tracker(argv):
     '''
     Return whether commandline indicates we are running the semaphore tracker
     '''
-    return (
-        (len(argv) >= 3) and
-        (argv[-2] == '-c') and
-        ('semaphore_tracker import main;' in sys.argv[-1])
-    )
+    if len(argv) >= 2 and argv[1] == '--multiprocessing-semaphore-tracker':
+        return True
+    else:
+        return False
 
 
 def is_forkserver(argv):
     '''
     Return whether commandline indicates we are running the forkserver
     '''
-    return (
-        (len(sys.argv) >= 3) and
-        (sys.argv[-2] == '-c') and
-        ('forkserver import main;' in sys.argv[-1])
-    )
+    if len(argv) >= 2 and argv[1] == '--multiprocessing-forkserver':
+        return True
+    else:
+        return False
 
 
 def freeze_support():
@@ -99,21 +97,20 @@ def freeze_support():
     # fix the command line for the semaphore tracker (unix)
     # we extract the single argument to the semaphore tracker's main()
     elif is_semaphore_tracker(sys.argv):
+        from multiprocessing.semaphore_tracker import main
         r = int(sys.argv[-1].rsplit('(')[1].split(')')[0])
-        from multiprocessing.semaphore_tracker import main;
         main(r)
         sys.exit()
     # fix the command line for the fork server (unix)
     # we extract the 3 args and keywords to the forkserver's main()
     elif is_forkserver(sys.argv):
+        from multiprocessing.forkserver import main
         cmd = sys.argv[-1]
         main_args = cmd.split('main(')[1].rsplit(')', 1)[0].split(', ', 3)
         listener_fd = int(main_args[0])
         alive_r = int(main_args[1])
         preload = ast.literal_eval(main_args[2])
         kwds = ast.literal_eval(main_args[3][2:])
-
-        from multiprocessing.forkserver import main
         main(listener_fd, alive_r, preload, **kwds)
         sys.exit()
 

From 7b49c0078945df9bc492c61792e5c7a97c42e7c3 Mon Sep 17 00:00:00 2001
From: Bo Bayles <bbayles@gmail.com>
Date: Sun, 14 Jan 2018 20:00:26 -0600
Subject: [PATCH 07/12] bpo-32146: Only use special command line arguments when
 frozen

---
 Lib/multiprocessing/forkserver.py        | 4 +++-
 Lib/multiprocessing/semaphore_tracker.py | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/Lib/multiprocessing/forkserver.py b/Lib/multiprocessing/forkserver.py
index 10342533a4a8b0..57ea6f584602c5 100644
--- a/Lib/multiprocessing/forkserver.py
+++ b/Lib/multiprocessing/forkserver.py
@@ -127,7 +127,9 @@ def ensure_running(self):
                     cmd %= (listener.fileno(), alive_r, self._preload_modules,
                             data)
                     exe = spawn.get_executable()
-                    args = [exe, '--multiprocessing-forkserver']
+                    args = [exe]
+                    if getattr(sys, 'frozen', False):
+                        args.append('--multiprocessing-forkserver')
                     args += util._args_from_interpreter_flags()
                     args += ['-c', cmd]
                     pid = util.spawnv_passfds(exe, args, fds_to_pass)
diff --git a/Lib/multiprocessing/semaphore_tracker.py b/Lib/multiprocessing/semaphore_tracker.py
index 0d909b3963163a..5055aa85d0fee2 100644
--- a/Lib/multiprocessing/semaphore_tracker.py
+++ b/Lib/multiprocessing/semaphore_tracker.py
@@ -66,7 +66,9 @@ def ensure_running(self):
                 fds_to_pass.append(r)
                 # process will out live us, so no need to wait on pid
                 exe = spawn.get_executable()
-                args = [exe, '--multiprocessing-semaphore-tracker']
+                args = [exe]
+                if getattr(sys, 'frozen', False):
+                    args.append('--multiprocessing-semaphore-tracker')
                 args += util._args_from_interpreter_flags()
                 args += ['-c', cmd % r]
                 pid = util.spawnv_passfds(exe, args, fds_to_pass)

From 26a63138cd40d5d447f57fdadbf4927b532f0e12 Mon Sep 17 00:00:00 2001
From: Bo Bayles <bbayles@gmail.com>
Date: Mon, 15 Jan 2018 13:13:01 -0600
Subject: [PATCH 08/12] bpo-32146: Factor out command line manipulation for
 testing

---
 Lib/multiprocessing/spawn.py      | 108 ++++++++++++++++++++----------
 Lib/test/_test_multiprocessing.py |  71 ++++++++++++++++++++
 2 files changed, 142 insertions(+), 37 deletions(-)

diff --git a/Lib/multiprocessing/spawn.py b/Lib/multiprocessing/spawn.py
index f850dcca5d2cc6..d7a0facc73bd9b 100644
--- a/Lib/multiprocessing/spawn.py
+++ b/Lib/multiprocessing/spawn.py
@@ -50,6 +50,7 @@ def get_executable():
 #
 #
 
+
 def is_forking(argv):
     '''
     Return whether commandline indicates we are forking
@@ -60,58 +61,91 @@ def is_forking(argv):
         return False
 
 
-def is_semaphore_tracker(argv):
+def get_forking_args(argv):
     '''
-    Return whether commandline indicates we are running the semaphore tracker
+    If the command line indicated we are forking, return (args, kwargs)
+    suitable for passing to spawn_main. Otherwise return None.
     '''
-    if len(argv) >= 2 and argv[1] == '--multiprocessing-semaphore-tracker':
-        return True
-    else:
-        return False
+    if not is_forking(argv):
+        return None
+
+    args = []
+    kwds = {}
+    for arg in argv[2:]:
+        name, value = arg.split('=')
+        if value == 'None':
+            kwds[name] = None
+        else:
+            kwds[name] = int(value)
 
+    return args, kwds
 
-def is_forkserver(argv):
+
+def get_semaphore_tracker_args(argv):
     '''
-    Return whether commandline indicates we are running the forkserver
+    If the command line indicates we are running the semaphore tracker,
+    return (args, kwargs) suitable for passing to semaphore_tracker.main.
+    Otherwise return None.
     '''
-    if len(argv) >= 2 and argv[1] == '--multiprocessing-forkserver':
-        return True
-    else:
-        return False
+    if len(argv) < 2 or argv[1] != '--multiprocessing-semaphore-tracker':
+        return None
+
+    # command ends with main(fd) - extract fd
+    r = int(argv[-1].rsplit('(')[1].split(')')[0])
+
+    args = [r]
+    kwds = {}
+    return args, kwds
+
+
+def get_forkserver_args(argv):
+    '''
+    If the command line indicates we are running the forkserver, return
+    (args, kwargs) suitable for passing to forkserver.main. Otherwise return
+    None.
+    '''
+    if len(argv) < 2 or argv[1] != '--multiprocessing-forkserver':
+        return None
+
+    # command ends with main(listener_fd, alive_r, preload, **kwds) - extract
+    # the args and kwarfs
+    # listener_fd and alive_r are integers
+    # preload is a list
+    # kwds map strings to lists
+    main_args = argv[-1].split('main(')[1].rsplit(')', 1)[0].split(', ', 3)
+    listener_fd = int(main_args[0])
+    alive_r = int(main_args[1])
+    preload = ast.literal_eval(main_args[2])
+
+    args = [listener_fd, alive_r, preload]
+    kwds = ast.literal_eval(main_args[3][2:])
+    return args, kwds
 
 
 def freeze_support():
     '''
-    Run code for process object if this in not the main process
+    Run code for process object if this in not the main process.
     '''
-    if is_forking(sys.argv):
-        kwds = {}
-        for arg in sys.argv[2:]:
-            name, value = arg.split('=')
-            if value == 'None':
-                kwds[name] = None
-            else:
-                kwds[name] = int(value)
-        spawn_main(**kwds)
+    argv = sys.argv
+
+    forking_args = get_forking_args(argv)
+    if forking_args is not None:
+        args, kwds = forking_args
+        spawn_main(*args, **kwds)
         sys.exit()
-    # fix the command line for the semaphore tracker (unix)
-    # we extract the single argument to the semaphore tracker's main()
-    elif is_semaphore_tracker(sys.argv):
+
+    semaphore_tracker_args = get_semaphore_tracker_args(argv)
+    if semaphore_tracker_args is not None:
         from multiprocessing.semaphore_tracker import main
-        r = int(sys.argv[-1].rsplit('(')[1].split(')')[0])
-        main(r)
+        args, kwds = semaphore_tracker_args
+        main(*args, **kwds)
         sys.exit()
-    # fix the command line for the fork server (unix)
-    # we extract the 3 args and keywords to the forkserver's main()
-    elif is_forkserver(sys.argv):
+
+    forkserver_args = get_forkserver_args(argv)
+    if get_forkserver_args(sys.argv):
         from multiprocessing.forkserver import main
-        cmd = sys.argv[-1]
-        main_args = cmd.split('main(')[1].rsplit(')', 1)[0].split(', ', 3)
-        listener_fd = int(main_args[0])
-        alive_r = int(main_args[1])
-        preload = ast.literal_eval(main_args[2])
-        kwds = ast.literal_eval(main_args[3][2:])
-        main(listener_fd, alive_r, preload, **kwds)
+        args, kwds = forkserver_args
+        main(*args, **kwds)
         sys.exit()
 
 
diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
index 05166b91ba832a..abf28587480346 100644
--- a/Lib/test/_test_multiprocessing.py
+++ b/Lib/test/_test_multiprocessing.py
@@ -3,6 +3,7 @@
 #
 
 import unittest
+import unittest.mock
 import queue as pyqueue
 import contextlib
 import time
@@ -4493,6 +4494,76 @@ def test_empty(self):
 
         proc.join()
 
+
+#
+# Issue 32146: freeze_support for fork, spawn, and forkserver start methods
+#
+
+class TestFreezeSupport(unittest.TestCase):
+    def setUp(self):
+        import multiprocessing.spawn
+        self.module = multiprocessing.spawn
+
+    def test_get_forking_args(self):
+        # Too few args
+        self.assertIsNone(self.module.get_forking_args(['./embed']))
+
+        # Wrong second argument
+        self.assertIsNone(
+            self.module.get_forking_args(['./embed', '-h'])
+        )
+
+        # All correct
+        args, kwds = self.module.get_forking_args(
+            ['./embed', '--multiprocessing-fork', 'pipe_handle=6', 'key=None']
+        )
+        self.assertEqual(args, [])
+        self.assertEqual(kwds, {'pipe_handle': 6, 'key': None})
+
+    def test_get_semaphore_tracker_args(self):
+        # Too few args
+        self.assertIsNone(self.module.get_semaphore_tracker_args(['.embed']))
+
+        # Wrong second argument
+        self.assertIsNone(self.module.get_semaphore_tracker_args(
+            ['./embed', '-h'])
+        )
+
+        # All correct
+        argv = [
+            './embed',
+            '--multiprocessing-semaphore-tracker',
+            'from multiprocessing.semaphore_tracker import main;main(5)'
+        ]
+        args, kwds = self.module.get_semaphore_tracker_args(argv)
+        self.assertEqual(args, [5])
+        self.assertEqual(kwds, {})
+
+    def test_get_forkserver_args(self):
+        # Too few args
+        self.assertFalse(self.module.get_forkserver_args(['./python-embed']))
+
+        # Wrong second argument
+        self.assertFalse(
+            self.module.get_forkserver_args(['./python-embed', '-h'])
+        )
+
+        # All correct
+        argv = [
+            './embed',
+            '--multiprocessing-forkserver',
+            (
+                "from multiprocessing.forkserver import main; "
+                "main(8, 9, ['__main__'], "
+                "**{'sys_path': ['/embed/lib', '/embed/lib/library.zip']})"
+            )
+        ]
+        args, kwds = self.module.get_forkserver_args(argv)
+        self.assertEqual(args, [8, 9, ['__main__']])
+        self.assertEqual(
+            kwds, {'sys_path': ['/embed/lib', '/embed/lib/library.zip']}
+        )
+
 #
 # Mixins
 #

From afdd5535fb92e19d3a77a8c6bc475b695aa0d4b2 Mon Sep 17 00:00:00 2001
From: Bo Bayles <bbayles@gmail.com>
Date: Mon, 15 Jan 2018 13:27:01 -0600
Subject: [PATCH 09/12] bpo-32146: Add note to docs about freeze_support on
 Unix

---
 Doc/library/multiprocessing.rst | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst
index 701f75279d838d..5aea3c8f8c49b4 100644
--- a/Doc/library/multiprocessing.rst
+++ b/Doc/library/multiprocessing.rst
@@ -942,12 +942,18 @@ Miscellaneous
           Process(target=f).start()
 
    If the ``freeze_support()`` line is omitted then trying to run the frozen
-   executable will raise :exc:`RuntimeError`.
+   executable will cause errors (e.g., :exc:`RuntimeError`). It is needed
+   when using the ``'spawn'`` and ``'forkserver'`` start methods.
+
 
    ``freeze_support()`` has no effect when invoked in a module that is being
    run normally by the Python interpreter (i.e., instead of by a frozen
    executable).
 
+.. versionchanged:: 3.7
+   Now supported on Unix (for the ``'spawn'`` and ``'forkserver'` start
+   methods)
+
 .. function:: get_all_start_methods()
 
    Returns a list of the supported start methods, the first of which

From d72742dea5d50032eaf636193e5956cd07873d82 Mon Sep 17 00:00:00 2001
From: Bo Bayles <bbayles@gmail.com>
Date: Mon, 15 Jan 2018 14:03:32 -0600
Subject: [PATCH 10/12] bpo-32146: Add missing backtick

---
 Doc/library/multiprocessing.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst
index 5aea3c8f8c49b4..cafe0a2288b8c6 100644
--- a/Doc/library/multiprocessing.rst
+++ b/Doc/library/multiprocessing.rst
@@ -951,7 +951,7 @@ Miscellaneous
    executable).
 
 .. versionchanged:: 3.7
-   Now supported on Unix (for the ``'spawn'`` and ``'forkserver'` start
+   Now supported on Unix (for the ``'spawn'`` and ``'forkserver'`` start
    methods)
 
 .. function:: get_all_start_methods()

From 97e6a9d748902353cfb4e730c471ff05810ca160 Mon Sep 17 00:00:00 2001
From: Bo Bayles <bbayles@gmail.com>
Date: Tue, 16 Jan 2018 06:12:14 -0600
Subject: [PATCH 11/12] bpo-32146: Fix and add test for extra preload modules

---
 Lib/multiprocessing/spawn.py      | 10 +++-------
 Lib/test/_test_multiprocessing.py |  4 ++--
 2 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/Lib/multiprocessing/spawn.py b/Lib/multiprocessing/spawn.py
index d7a0facc73bd9b..019467ae1b9d7c 100644
--- a/Lib/multiprocessing/spawn.py
+++ b/Lib/multiprocessing/spawn.py
@@ -112,13 +112,9 @@ def get_forkserver_args(argv):
     # listener_fd and alive_r are integers
     # preload is a list
     # kwds map strings to lists
-    main_args = argv[-1].split('main(')[1].rsplit(')', 1)[0].split(', ', 3)
-    listener_fd = int(main_args[0])
-    alive_r = int(main_args[1])
-    preload = ast.literal_eval(main_args[2])
-
-    args = [listener_fd, alive_r, preload]
-    kwds = ast.literal_eval(main_args[3][2:])
+    parsed = ast.parse(argv[-1])
+    args = [ast.literal_eval(parsed.body[1].value.args[i]) for i in range(3)]
+    kwds = ast.literal_eval(parsed.body[1].value.keywords[0].value)
     return args, kwds
 
 
diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
index abf28587480346..b2bb386711c87a 100644
--- a/Lib/test/_test_multiprocessing.py
+++ b/Lib/test/_test_multiprocessing.py
@@ -4554,12 +4554,12 @@ def test_get_forkserver_args(self):
             '--multiprocessing-forkserver',
             (
                 "from multiprocessing.forkserver import main; "
-                "main(8, 9, ['__main__'], "
+                "main(8, 9, ['__main__', 'other'], "
                 "**{'sys_path': ['/embed/lib', '/embed/lib/library.zip']})"
             )
         ]
         args, kwds = self.module.get_forkserver_args(argv)
-        self.assertEqual(args, [8, 9, ['__main__']])
+        self.assertEqual(args, [8, 9, ['__main__', 'other']])
         self.assertEqual(
             kwds, {'sys_path': ['/embed/lib', '/embed/lib/library.zip']}
         )

From f0ca86b5fb59d3cd84dd2f612103823c90f12fca Mon Sep 17 00:00:00 2001
From: Bo Bayles <bbayles@gmail.com>
Date: Mon, 29 Jan 2018 14:03:03 -0600
Subject: [PATCH 12/12] bpo-32146: Fix up comments

---
 Lib/multiprocessing/spawn.py | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/Lib/multiprocessing/spawn.py b/Lib/multiprocessing/spawn.py
index 019467ae1b9d7c..04c5ff33f85efc 100644
--- a/Lib/multiprocessing/spawn.py
+++ b/Lib/multiprocessing/spawn.py
@@ -90,7 +90,7 @@ def get_semaphore_tracker_args(argv):
     if len(argv) < 2 or argv[1] != '--multiprocessing-semaphore-tracker':
         return None
 
-    # command ends with main(fd) - extract fd
+    # command ends with main(fd) - extract the fd.
     r = int(argv[-1].rsplit('(')[1].split(')')[0])
 
     args = [r]
@@ -108,10 +108,8 @@ def get_forkserver_args(argv):
         return None
 
     # command ends with main(listener_fd, alive_r, preload, **kwds) - extract
-    # the args and kwarfs
-    # listener_fd and alive_r are integers
-    # preload is a list
-    # kwds map strings to lists
+    # the args and kwargs. listener_fd and alive_r are integers.
+    # preload is a list. The kwds map strings to lists.
     parsed = ast.parse(argv[-1])
     args = [ast.literal_eval(parsed.body[1].value.args[i]) for i in range(3)]
     kwds = ast.literal_eval(parsed.body[1].value.keywords[0].value)