[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 42a139e)

Author: serhiy-storchaka

Lib/bdb.py

@@ -616,11 +616,23 @@ def runctx(self, cmd, globals, locals):
 
     # This method is more useful to debug a single function call.
 
-    def runcall(self, func, *args, **kwds):
+    def runcall(*args, **kwds):
         """Debug a single function call.
 
         Return the result of the function call.
         """
+        if len(args) >= 2:
+            self, func, *args = args
+        elif not args:
+            raise TypeError("descriptor 'runcall' of 'Bdb' object "
+                            "needs an argument")
+        elif 'func' in kwds:
+            func = kwds.pop('func')
+            self, *args = args
+        else:
+            raise TypeError('runcall expected at least 1 positional argument, '
+                            'got %d' % (len(args)-1))
+
         self.reset()
         sys.settrace(self.trace_dispatch)
         res = None

Lib/cProfile.py

@@ -103,7 +103,19 @@ def runctx(self, cmd, globals, locals):
         return self
 
     # This method is more useful to profile a single function call.
-    def runcall(self, func, *args, **kw):
+    def runcall(*args, **kw):
+        if len(args) >= 2:
+            self, func, *args = args
+        elif not args:
+            raise TypeError("descriptor 'runcall' of 'Profile' object "
+                            "needs an argument")
+        elif 'func' in kw:
+            func = kw.pop('func')
+            self, *args = args
+        else:
+            raise TypeError('runcall expected at least 1 positional argument, '
+                            'got %d' % (len(args)-1))
+
         self.enable()
         try:
             return func(*args, **kw)

Lib/concurrent/futures/_base.py

@@ -536,7 +536,7 @@ def set_exception(self, exception):
 class Executor(object):
     """This is an abstract base class for concrete asynchronous executors."""
 
-    def submit(self, fn, *args, **kwargs):
+    def submit(*args, **kwargs):
         """Submits a callable to be executed with the given arguments.
 
         Schedules the callable to be executed as fn(*args, **kwargs) and returns
@@ -545,6 +545,15 @@ def submit(self, fn, *args, **kwargs):
         Returns:
             A Future representing the given call.
         """
+        if len(args) >= 2:
+            pass
+        elif not args:
+            raise TypeError("descriptor 'submit' of 'Executor' object "
+                            "needs an argument")
+        elif 'fn' not in kwargs:
+            raise TypeError('submit expected at least 1 positional argument, '
+                            'got %d' % (len(args)-1))
+
         raise NotImplementedError()
 
     def map(self, fn, *iterables, timeout=None, chunksize=1):

Lib/concurrent/futures/process.py

@@ -593,7 +593,19 @@ def _adjust_process_count(self):
             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)

Lib/concurrent/futures/thread.py

@@ -142,7 +142,19 @@ def __init__(self, max_workers=None, thread_name_prefix='',
         self._initializer = initializer
         self._initargs = initargs
 
-    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 'ThreadPoolExecutor' 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 BrokenThreadPool(self._broken)

Lib/contextlib.py

@@ -378,7 +378,8 @@ def _exit_wrapper(exc_type, exc, tb):
         return _exit_wrapper
 
     @staticmethod
-    def _create_cb_wrapper(callback, *args, **kwds):
+    def _create_cb_wrapper(*args, **kwds):
+        callback, *args = args
         def _exit_wrapper(exc_type, exc, tb):
             callback(*args, **kwds)
         return _exit_wrapper
@@ -427,11 +428,23 @@ def enter_context(self, cm):
         self._push_cm_exit(cm, _exit)
         return result
 
-    def callback(self, callback, *args, **kwds):
+    def callback(*args, **kwds):
         """Registers an arbitrary callback and arguments.
 
         Cannot suppress exceptions.
         """
+        if len(args) >= 2:
+            self, callback, *args = args
+        elif not args:
+            raise TypeError("descriptor 'callback' of '_BaseExitStack' object "
+                            "needs an argument")
+        elif 'callback' in kwds:
+            callback = kwds.pop('callback')
+            self, *args = args
+        else:
+            raise TypeError('callback expected at least 1 positional argument, '
+                            'got %d' % (len(args)-1))
+
         _exit_wrapper = self._create_cb_wrapper(callback, *args, **kwds)
 
         # We changed the signature, so using @wraps is not appropriate, but
@@ -540,7 +553,8 @@ async def _exit_wrapper(exc_type, exc, tb):
         return _exit_wrapper
 
     @staticmethod
-    def _create_async_cb_wrapper(callback, *args, **kwds):
+    def _create_async_cb_wrapper(*args, **kwds):
+        callback, *args = args
         async def _exit_wrapper(exc_type, exc, tb):
             await callback(*args, **kwds)
         return _exit_wrapper
@@ -575,11 +589,23 @@ def push_async_exit(self, exit):
             self._push_async_cm_exit(exit, exit_method)
         return exit  # Allow use as a decorator
 
-    def push_async_callback(self, callback, *args, **kwds):
+    def push_async_callback(*args, **kwds):
         """Registers an arbitrary coroutine function and arguments.
 
         Cannot suppress exceptions.
         """
+        if len(args) >= 2:
+            self, callback, *args = args
+        elif not args:
+            raise TypeError("descriptor 'push_async_callback' of "
+                            "'AsyncExitStack' object needs an argument")
+        elif 'callback' in kwds:
+            callback = kwds.pop('callback')
+            self, *args = args
+        else:
+            raise TypeError('push_async_callback expected at least 1 '
+                            'positional argument, got %d' % (len(args)-1))
+
         _exit_wrapper = self._create_async_cb_wrapper(callback, *args, **kwds)
 
         # We changed the signature, so using @wraps is not appropriate, but

Lib/curses/__init__.py

@@ -60,14 +60,22 @@ def start_color():
 # raises an exception, wrapper() will restore the terminal to a sane state so
 # you can read the resulting traceback.
 
-def wrapper(func, *args, **kwds):
+def wrapper(*args, **kwds):
     """Wrapper function that initializes curses and calls another function,
     restoring normal keyboard/screen behavior on error.
     The callable object 'func' is then passed the main window 'stdscr'
     as its first argument, followed by any other arguments passed to
     wrapper().
     """
 
+    if args:
+        func, *args = args
+    elif 'func' in kwds:
+        func = kwds.pop('func')
+    else:
+        raise TypeError('wrapper expected at least 1 positional argument, '
+                        'got %d' % len(args))
+
     try:
         # Initialize curses
         stdscr = initscr()

Lib/functools.py

@@ -323,7 +323,20 @@ class partialmethod(object):
     callables as instance methods.
     """
 
-    def __init__(self, func, *args, **keywords):
+    def __init__(*args, **keywords):
+        if len(args) >= 2:
+            self, func, *args = args
+        elif not args:
+            raise TypeError("descriptor '__init__' of partialmethod "
+                            "needs an argument")
+        elif 'func' in keywords:
+            func = keywords.pop('func')
+            self, *args = args
+        else:
+            raise TypeError("type 'partialmethod' takes at least one argument, "
+                            "got %d" % (len(args)-1))
+        args = tuple(args)
+
         if not callable(func) and not hasattr(func, "__get__"):
             raise TypeError("{!r} is not callable or a descriptor"
                                  .format(func))

Lib/multiprocessing/managers.py

@@ -351,10 +351,30 @@ def shutdown(self, c):
         finally:
             self.stop_event.set()
 
-    def create(self, c, typeid, *args, **kwds):
+    def create(*args, **kwds):
         '''
         Create a new shared object and return its id
         '''
+        if len(args) >= 3:
+            self, c, typeid, *args = args
+        elif not args:
+            raise TypeError("descriptor 'create' of 'Server' object "
+                            "needs an argument")
+        else:
+            if 'typeid' not in kwds:
+                raise TypeError('create expected at least 2 positional '
+                                'arguments, got %d' % (len(args)-1))
+            typeid = kwds.pop('typeid')
+            if len(args) >= 2:
+                self, c, *args = args
+            else:
+                if 'c' not in kwds:
+                    raise TypeError('create expected at least 2 positional '
+                                    'arguments, got %d' % (len(args)-1))
+                c = kwds.pop('c')
+                self, *args = args
+        args = tuple(args)
+
         with self.mutex:
             callable, exposed, method_to_typeid, proxytype = \
                       self.registry[typeid]
@@ -576,10 +596,13 @@ def _run_server(cls, registry, address, authkey, serializer, writer,
         util.info('manager serving at %r', server.address)
         server.serve_forever()
 
-    def _create(self, typeid, *args, **kwds):
+    def _create(*args, **kwds):
         '''
         Create a new shared object; return the token and exposed tuple
         '''
+        self, typeid, *args = args
+        args = tuple(args)
+
         assert self._state.value == State.STARTED, 'server not yet started'
         conn = self._Client(self._address, authkey=self._authkey)
         try:

Lib/profile.py

@@ -425,7 +425,19 @@ def runctx(self, cmd, globals, locals):
         return self
 
     # This method is more useful to profile a single function call.
-    def runcall(self, func, *args, **kw):
+    def runcall(*args, **kw):
+        if len(args) >= 2:
+            self, func, *args = args
+        elif not args:
+            raise TypeError("descriptor 'runcall' of 'Profile' object "
+                            "needs an argument")
+        elif 'func' in kw:
+            func = kw.pop('func')
+            self, *args = args
+        else:
+            raise TypeError('runcall expected at least 1 positional argument, '
+                            'got %d' % (len(args)-1))
+
         self.set_cmd(repr(func))
         sys.setprofile(self.dispatcher)
         try: