remove -s alias for --sort-columns

Cliff normally uses short option name aliases which are global
in to the CLI.  We want commands to not use them due to the
limited number and ease of collision.  However this one
was already in use by a well-known plugin so we will not take it.

Change-Id: Id348dad450b52716b82d7852d6378ecc48808f26
Closes-Bug: #1743578
Signed-off-by: Doug Hellmann <doug@doughellmann.com>

cliff/lister.py

@@ -50,7 +50,7 @@ class Lister(display.DisplayCommandBase):
         parser = super(Lister, self).get_parser(prog_name)
         group = self._formatter_group
         group.add_argument(
-            '-s', '--sort-column',
+            '--sort-column',
             action='append',
             default=[],
             dest='sort_columns',

cliff/tests/test_command.py

@@ -10,6 +10,7 @@
 #  License for the specific language governing permissions and limitations
 #  under the License.
 
+import argparse
 import functools
 
 from cliff import command
@@ -42,6 +43,10 @@ class TestCommand(command.Command):
             help="The quick brown fox jumps "
                  "over the lazy dog.",
         )
+        parser.add_argument(
+            '-z',
+            help='used in TestArgumentParser',
+        )
         return parser
 
     def take_action(self, parsed_args):
@@ -128,3 +133,18 @@ class TestHelp(base.TestBase):
             width=78,
         )
         self.assertIn(expected_help_message, parser.format_help())
+
+
+class TestArgumentParser(base.TestBase):
+
+    def test_option_name_collision(self):
+        cmd = TestCommand(None, None)
+        parser = cmd.get_parser('NAME')
+        # We should have an exception registering an option with a
+        # name that already exists because we do not want commands to
+        # override global options.
+        self.assertRaises(
+            argparse.ArgumentError,
+            parser.add_argument,
+            '-z',
+        )