bpo-19764: Fixed the handle_list warning with close_fds=True

Also fixed the documentation for handle_list.

Author: segevfiner

Doc/library/subprocess.rst

@@ -809,7 +809,7 @@ on Windows.
       Supported attributes:
 
       **handle_list**
-         When *close_fds* is :const:`True`, supplies a list of
+         When *close_fds* is :const:`False`, supplies a list of
          handles that will be inherited.
 
       .. versionadded:: 3.7

Lib/subprocess.py

@@ -981,9 +981,9 @@ def _execute_child(self, args, executable, preexec_fn, close_fds,
                 startupinfo.hStdError = errwrite
 
             attribute_list = startupinfo.lpAttributeList
-            have_handle_list = (attribute_list and
-                                "handle_list" in attribute_list and
-                                attribute_list["handle_list"])
+            have_handle_list = bool(attribute_list and
+                                    "handle_list" in attribute_list and
+                                    attribute_list["handle_list"])
 
             # If we were given an handle_list or need to create one
             if have_handle_list or (use_std_handles and close_fds):
@@ -997,7 +997,7 @@ def _execute_child(self, args, executable, preexec_fn, close_fds,
                 handle_list[:] = self._filter_handle_list(handle_list)
 
                 if handle_list:
-                    if have_handle_list and not close_fds:
+                    if have_handle_list and close_fds:
                         warnings.warn("startupinfo.lpAttributeList['handle_list'] "
                                       "overriding close_fds", RuntimeWarning)