Fix bug where options with a single letter were being considered as numbers.

2 files changed, 18 insertions, 1 deletions

diff --git a/argparse.py b/argparse.py
index 2ba966c..1ab2a53 100644
--- a/argparse.py
+++ b/argparse.py
@@ -1203,7 +1203,7 @@ class _ActionsContainer(object):
         self._defaults = {}
 
         # determines whether an "option" looks like a negative number
-        self._negative_number_matcher = _re.compile(r'^-\d+|-\d*.\d+$')
+        self._negative_number_matcher = _re.compile(r'^-\d+$|^-\d*\.\d+$')
 
         # whether or not there are any optionals that look like negative
         # numbers -- uses a list so it can be shared and edited
diff --git a/test/test_argparse.py b/test/test_argparse.py
index 8860592..0bd06ca 100644
--- a/test/test_argparse.py
+++ b/test/test_argparse.py
@@ -1121,6 +1121,23 @@ class TestOptionalsNumericAndPositionals(ParserTestCase):
     ]
 
 
+class TestOptionalsAlmostNumericAndPositionals(ParserTestCase):
+    """Tests negative number args when almost numeric options are present"""
+
+    argument_signatures = [
+        Sig('x', nargs='?'),
+        Sig('-k4', dest='y', action='store_true'),
+    ]
+    failures = ['-k3']
+    successes = [
+        ('', NS(x=None, y=False)),
+        ('-2', NS(x='-2', y=False)),
+        ('a', NS(x='a', y=False)),
+        ('-k4', NS(x=None, y=True)),
+        ('-k4 a', NS(x='a', y=True)),
+    ]
+
+
 class TestEmptyAndSpaceContainingArguments(ParserTestCase):
 
     argument_signatures = [