[3.7] bpo-36492: Fix passing special keyword arguments to some functions. (GH-12637) (GH-12645)

The following arguments can be passed as keyword arguments for passing
to other function if the corresponding required argument is passed as
positional:

- "func" in functools.partialmethod(), weakref.finalize(),
  profile.Profile.runcall(), cProfile.Profile.runcall(),
  bdb.Bdb.runcall(), trace.Trace.runfunc() and
  curses.wrapper().
- "function" in unittest.addModuleCleanup() and
  unittest.TestCase.addCleanup().
- "fn" in the submit() method of concurrent.futures.ThreadPoolExecutor
  and concurrent.futures.ProcessPoolExecutor.
- "callback" in contextlib.ExitStack.callback(),
  contextlib.AsyncExitStack.callback() and
  contextlib.AsyncExitStack.push_async_callback().
- "c" and "typeid" in multiprocessing.managers.Server.create().
- "obj" in weakref.finalize().

(cherry picked from commit 42a139ed88c487f325a241c6ee8b308b3c045975)

1 files changed, 13 insertions, 1 deletions

diff --git a/Lib/concurrent/futures/process.py b/Lib/concurrent/futures/process.py
index ce7d642..8a0ed98 100644
--- a/Lib/concurrent/futures/process.py
+++ b/Lib/concurrent/futures/process.py
@@ -593,7 +593,19 @@ class ProcessPoolExecutor(_base.Executor):
             p.start()
             self._processes[p.pid] = p
 
-    def submit(self, fn, *args, **kwargs):
+    def submit(*args, **kwargs):
+        if len(args) >= 2:
+            self, fn, *args = args
+        elif not args:
+            raise TypeError("descriptor 'submit' of 'ProcessPoolExecutor' object "
+                            "needs an argument")
+        elif 'fn' in kwargs:
+            fn = kwargs.pop('fn')
+            self, *args = args
+        else:
+            raise TypeError('submit expected at least 1 positional argument, '
+                            'got %d' % (len(args)-1))
+
         with self._shutdown_lock:
             if self._broken:
                 raise BrokenProcessPool(self._broken)