Merge "add argparse conflict handler "ignore""

3 files changed, 106 insertions, 5 deletions

diff --git a/cliff/_argparse.py b/cliff/_argparse.py
index e48dc79..5358e72 100644
--- a/cliff/_argparse.py
+++ b/cliff/_argparse.py
@@ -14,11 +14,14 @@
 
 from __future__ import absolute_import
 from argparse import *  # noqa
+import argparse
 import sys
+import warnings
 
 
-if sys.version_info < (3, 5):
-    class ArgumentParser(ArgumentParser):  # noqa
+class ArgumentParser(argparse.ArgumentParser):
+
+    if sys.version_info < (3, 5):
         def __init__(self, *args, **kwargs):
             self.allow_abbrev = kwargs.pop("allow_abbrev", True)
             super(ArgumentParser, self).__init__(*args, **kwargs)
@@ -28,3 +31,76 @@ if sys.version_info < (3, 5):
                 return super(ArgumentParser, self)._get_option_tuples(
                     option_string)
             return ()
+
+    # NOTE(dhellmann): We have to override the methods for creating
+    # groups to return our objects that know how to deal with the
+    # special conflict handler.
+
+    def add_argument_group(self, *args, **kwargs):
+        group = _ArgumentGroup(self, *args, **kwargs)
+        self._action_groups.append(group)
+        return group
+
+    def add_mutually_exclusive_group(self, **kwargs):
+        group = _MutuallyExclusiveGroup(self, **kwargs)
+        self._mutually_exclusive_groups.append(group)
+        return group
+
+    def _handle_conflict_ignore(self, action, conflicting_actions):
+        _handle_conflict_ignore(
+            self,
+            self._option_string_actions,
+            action,
+            conflicting_actions,
+        )
+
+
+def _handle_conflict_ignore(container, option_string_actions,
+                            new_action, conflicting_actions):
+
+    # Remember the option strings the new action starts with so we can
+    # restore them as part of error reporting if we need to.
+    original_option_strings = new_action.option_strings
+
+    # Remove all of the conflicting option strings from the new action
+    # and report an error if none are left at the end.
+    for option_string, action in conflicting_actions:
+
+        # remove the conflicting option from the new action
+        new_action.option_strings.remove(option_string)
+        warnings.warn(
+            ('Ignoring option string {} for new action '
+             'because it conflicts with an existing option.').format(
+                 option_string))
+
+        # if the option now has no option string, remove it from the
+        # container holding it
+        if not new_action.option_strings:
+            new_action.option_strings = original_option_strings
+            raise argparse.ArgumentError(
+                new_action,
+                ('Cannot resolve conflicting option string, '
+                 'all names conflict.'),
+            )
+
+
+class _ArgumentGroup(argparse._ArgumentGroup):
+
+    def _handle_conflict_ignore(self, action, conflicting_actions):
+        _handle_conflict_ignore(
+            self,
+            self._option_string_actions,
+            action,
+            conflicting_actions,
+        )
+
+
+class _MutuallyExclusiveGroup(argparse._MutuallyExclusiveGroup):
+
+    def _handle_conflict_ignore(self, action, conflicting_actions):
+        _handle_conflict_ignore(
+            self,
+            self._option_string_actions,
+            action,
+            conflicting_actions,
+        )
diff --git a/cliff/command.py b/cliff/command.py
index 13b872d..760832b 100644
--- a/cliff/command.py
+++ b/cliff/command.py
@@ -156,6 +156,7 @@ class Command(object):
             epilog=self.get_epilog(),
             prog=prog_name,
             formatter_class=_SmartHelpFormatter,
+            conflict_handler='ignore',
         )
         for hook in self._hooks:
             hook.obj.get_parser(parser)
diff --git a/cliff/tests/test_command.py b/cliff/tests/test_command.py
index 6aecff3..29c8c33 100644
--- a/cliff/tests/test_command.py
+++ b/cliff/tests/test_command.py
@@ -45,7 +45,9 @@ class TestCommand(command.Command):
         )
         parser.add_argument(
             '-z',
-            help='used in TestArgumentParser',
+            dest='zippy',
+            default='zippy-default',
+            help='defined in TestCommand and used in TestArgumentParser',
         )
         return parser
 
@@ -141,10 +143,32 @@ class TestArgumentParser(base.TestBase):
         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.
+        # name that already exists because we configure the argument
+        # parser to ignore conflicts but this option has no other name
+        # to be used.
         self.assertRaises(
             argparse.ArgumentError,
             parser.add_argument,
             '-z',
         )
+
+    def test_option_name_collision_with_alias(self):
+        cmd = TestCommand(None, None)
+        parser = cmd.get_parser('NAME')
+        # We not should have an exception registering an option with a
+        # name that already exists because we configure the argument
+        # parser to ignore conflicts and this option can be added as
+        # --zero even if the -z is ignored.
+        parser.add_argument('-z', '--zero')
+
+    def test_resolve_option_with_name_collision(self):
+        cmd = TestCommand(None, None)
+        parser = cmd.get_parser('NAME')
+        parser.add_argument(
+            '-z', '--zero',
+            dest='zero',
+            default='zero-default',
+        )
+        args = parser.parse_args(['-z', 'foo', 'a', 'b'])
+        self.assertEqual(args.zippy, 'foo')
+        self.assertEqual(args.zero, 'zero-default')