Remove the warning of getargspec removal

The method getargspec is deprecated and will be removed [1].
This produces a lot of deprecation warning in the logs which is
noisy. This patch proposes to use getfullargspec if it is available.
For python 2 compatibility, we need to fall back to getargspec.

[1] https://docs.python.org/3/library/inspect.html#inspect.getargspec

Change-Id: Ide7d9ca99e0edf23261b5d47f35766aaaac9059b

cliff/app.py

@@ -14,7 +14,6 @@
 """
 
 import codecs
-import inspect
 import locale
 import logging
 import logging.handlers
@@ -384,7 +383,7 @@ class App(object):
             return 2
         cmd_factory, cmd_name, sub_argv = subcommand
         kwargs = {}
-        if 'cmd_name' in inspect.getargspec(cmd_factory.__init__).args:
+        if 'cmd_name' in utils.getargspec(cmd_factory.__init__).args:
             kwargs['cmd_name'] = cmd_name
         cmd = cmd_factory(self, self.options, **kwargs)
         err = None

cliff/commandmanager.py

@@ -13,11 +13,12 @@
 """Discover and lookup command plugins.
 """
 
-import inspect
 import logging
 
 import pkg_resources
 
+from . import utils
+
 
 LOG = logging.getLogger(__name__)
 
@@ -103,7 +104,7 @@ class CommandManager(object):
                 else:
                     # NOTE(dhellmann): Some fake classes don't take
                     # require as an argument. Yay?
-                    arg_spec = inspect.getargspec(cmd_ep.load)
+                    arg_spec = utils.getargspec(cmd_ep.load)
                     if 'require' in arg_spec[0]:
                         cmd_factory = cmd_ep.load(require=False)
                     else:

cliff/help.py

@@ -16,6 +16,7 @@ import sys
 import traceback
 
 from . import command
+from . import utils
 
 
 class HelpAction(argparse.Action):
@@ -47,7 +48,7 @@ class HelpAction(argparse.Action):
                 continue
             try:
                 kwargs = {}
-                if 'cmd_name' in inspect.getargspec(factory.__init__).args:
+                if 'cmd_name' in utils.getargspec(factory.__init__).args:
                     kwargs['cmd_name'] = name
                 cmd = factory(app, None, **kwargs)
                 if cmd.deprecated:
@@ -100,7 +101,7 @@ class HelpCommand(command.Command):
                 return
             self.app_args.cmd = search_args
             kwargs = {}
-            if 'cmd_name' in inspect.getargspec(cmd_factory.__init__).args:
+            if 'cmd_name' in utils.getargspec(cmd_factory.__init__).args:
                 kwargs['cmd_name'] = cmd_name
             cmd = cmd_factory(self.app, self.app_args, **kwargs)
             full_name = (cmd_name

cliff/utils.py

@@ -13,6 +13,7 @@
 
 import codecs
 import ctypes
+import inspect
 import os
 import struct
 import sys
@@ -28,6 +29,12 @@ import six
 COST = {'w': 0, 's': 2, 'a': 1, 'd': 3}
 
 
+if hasattr(inspect, 'getfullargspec'):
+    getargspec = inspect.getfullargspec
+else:
+    getargspec = inspect.getargspec
+
+
 def damerau_levenshtein(s1, s2, cost):
     """Calculates the Damerau-Levenshtein distance between two strings.