Now we refrain from changing underscores in postional arguments to dashes

Author: martinjm97

tap/tap.py

@@ -242,7 +242,9 @@ def _add_argument(self, *name_or_flags, **kwargs) -> None:
                     kwargs['type'] = var_type
 
         if self._underscores_to_dashes:
-            name_or_flags = [name_or_flag.replace('_', '-') for name_or_flag in name_or_flags]
+            # Replace "_" with "-" for arguments that aren't positional
+            name_or_flags = tuple(name_or_flag.replace('_', '-') if name_or_flag.startswith('-') else name_or_flag
+                                  for name_or_flag in name_or_flags)
 
         super(Tap, self).add_argument(*name_or_flags, **kwargs)
 

tests/test_integration.py

@@ -1349,6 +1349,30 @@ def my_property(self):
         self.assertEqual(args._get_class_dict(), result)
 
 
+class TestPositionalArguments(TestCase):
+
+    def test_underscores_to_dashes_does_not_modify_positional(self):
+        class PositionalTap(Tap):
+            under_score: int
+
+            def configure(self):
+                self.add_argument('under_score')
+
+        args = PositionalTap(underscores_to_dashes=True).parse_args(['1'])
+
+        self.assertEqual(args.under_score, 1)
+
+    def test_positional_maintains_types(self):
+        class PositionalTap(Tap):
+            a: int
+
+            def configure(self) -> None:
+                self.add_argument('a')
+
+        args = PositionalTap().parse_args(['1'])
+
+        self.assertEqual(args.a, 1)
+
 """
 - crash if default type not supported
 - user specifying process_args