app,command: disallow abbrev by default

By default, abbrev support is enabled in argparse, which can mangle
cliff arguments as shown in the test since all the arguments from all
the commands are not registered at once in the parser, but are parsed in
multiple passes.

It's a nasty behaviour that by default can break application using cliff
without having them noticing. Since I don't think anyone is really
relying on the abbrev behaviour for real, let's just disable it
altogether.

Depends-On: I903ce9564a83d3ee69f4efeb726d3c2d3ff69bbb
Change-Id: I77127e364e938418de36b09c0b80644b77d62336

cliff/app.py

@@ -122,6 +122,7 @@ class App(object):
         parser = argparse.ArgumentParser(
             description=description,
             add_help=False,
+            allow_abbrev=False,
             **argparse_kwargs
         )
         parser.add_argument(

cliff/command.py

@@ -34,6 +34,7 @@ class Command(object):
         parser = argparse.ArgumentParser(
             description=self.get_description(),
             prog=prog_name,
+            allow_abbrev=False,
         )
         return parser
 

cliff/tests/test_app.py

@@ -264,8 +264,7 @@ def test_option_parser_abbrev_issue():
         def build_option_parser(self, description, version):
             parser = super(MyApp, self).build_option_parser(
                 description,
-                version,
-                argparse_kwargs={'allow_abbrev': False})
+                version)
             parser.add_argument('--endpoint')
             return parser