Fix positional arg corner case, help formatting for tyro.conf.arg()

examples/04_additional/06_conf.py

@@ -7,6 +7,7 @@
 
 Usage:
 `python ./06_conf.py --help`
+`python ./06_conf.py 5 --boolean True`
 """
 
 import dataclasses
@@ -34,15 +35,25 @@ class CommitArgs:
 
 @dataclasses.dataclass
 class Args:
-    # A boolean field with flag conversion turned off.
-    boolean: tyro.conf.FlagConversionOff[bool] = False
-
     # A numeric field parsed as a positional argument.
     positional: tyro.conf.Positional[int] = 3
 
+    # A boolean field with flag conversion turned off.
+    boolean: tyro.conf.FlagConversionOff[bool] = False
+
     # A numeric field that can't be changed via the CLI.
     fixed: tyro.conf.Fixed[int] = 5
 
+    # A field with manually overridden properties.
+    manual: Annotated[
+        str,
+        tyro.conf.arg(
+            name="renamed",
+            metavar="STRING",
+            help="A field with manually overridden properties!",
+        ),
+    ] = "Hello"
+
     # A union over nested structures, but without subcommand generation. When a default
     # is provided, the type is simply fixed to that default.
     union_without_subcommand: tyro.conf.AvoidSubcommands[

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "tyro"
-version = "0.3.32"
+version = "0.3.33"
 description = "Strongly typed, zero-effort CLI interfaces"
 authors = ["brentyi <[email protected]>"]
 include = ["./tyro/**/*"]

tests/test_conf.py

@@ -527,3 +527,19 @@ def main(x: Any = Struct()) -> int:
 
     assert tyro.cli(main, args=[]) == 5
     assert tyro.cli(main, args=["--x.nice", "3"]) == 3
+
+
+def test_positional():
+    def main(x: tyro.conf.Positional[int], y: int) -> int:
+        return x + y
+
+    assert tyro.cli(main, args="5 --y 3".split(" ")) == 8
+    assert tyro.cli(main, args="--y 3 5".split(" ")) == 8
+
+
+def test_positional_order_swap():
+    def main(x: int, y: tyro.conf.Positional[int]) -> int:
+        return x + y
+
+    assert tyro.cli(main, args="5 --x 3".split(" ")) == 8
+    assert tyro.cli(main, args="--x 3 5".split(" ")) == 8

tyro/_arguments.py

@@ -65,13 +65,8 @@ def add_argument(
 
         # Apply overrides in our arg configuration object.
         # Note that the `name` field is applied when the field object is instantiated!
-        kwargs.update(
-            {
-                k: v
-                for k, v in vars(self.field.argconf).items()
-                if v is not None and k != "name"
-            }
-        )
+        if self.field.argconf.metavar is not None:
+            kwargs["metavar"] = self.field.argconf.metavar
 
         # Add argument! Note that the name must be passed in as a position argument.
         arg = parser.add_argument(name_or_flag, **kwargs)
@@ -314,13 +309,13 @@ def _rule_generate_helptext(
 
     help_parts = []
 
-    docstring_help = arg.field.helptext
+    primary_help = arg.field.helptext
 
-    if docstring_help is not None and docstring_help != "":
+    if primary_help is not None and primary_help != "":
         # Note that the percent symbol needs some extra handling in argparse.
         # https://stackoverflow.com/questions/21168120/python-argparse-errors-with-in-help-string
-        docstring_help = docstring_help.replace("%", "%%")
-        help_parts.append(_rich_tag_if_enabled(docstring_help, "helptext"))
+        primary_help = primary_help.replace("%", "%%")
+        help_parts.append(_rich_tag_if_enabled(primary_help, "helptext"))
 
     default = lowered.default
     if lowered.is_fixed():

tyro/_calling.py

@@ -163,7 +163,7 @@ def get_value_from_arg(prefixed_field_name: str) -> Any:
                 consumed_keywords |= consumed_keywords_child
 
         if value is not _fields.EXCLUDE_FROM_CALL:
-            if field.is_positional():
+            if field.is_positional_call():
                 args.append(value)
             else:
                 kwargs[field.call_argname] = value

tyro/_fields.py

@@ -83,6 +83,7 @@ def make(
         else:
             assert len(argconfs) == 1
             (argconf,) = argconfs
+            helptext = argconf.help
 
         typ, inferred_markers = _resolver.unwrap_annotated(typ, _markers.Marker)
         return FieldDefinition(
@@ -102,13 +103,23 @@ def add_markers(self, markers: Tuple[_markers.Marker, ...]) -> FieldDefinition:
         )
 
     def is_positional(self) -> bool:
+        """Returns True if the argument should be positional in the commandline."""
         return (
             # Explicit positionals.
             _markers.Positional in self.markers
             # Dummy dataclasses should have a single positional field.
             or self.name == _strings.dummy_field_name
         )
 
+    def is_positional_call(self) -> bool:
+        """Returns True if the argument should be positional in underlying Python call."""
+        return (
+            # Explicit positionals.
+            _markers._PositionalCall in self.markers
+            # Dummy dataclasses should have a single positional field.
+            or self.name == _strings.dummy_field_name
+        )
+
 
 class PropagatingMissingType(_singleton.Singleton):
     pass
@@ -646,7 +657,7 @@ def _field_list_from_params(
                 typ=hints[param.name],
                 default=default,
                 helptext=helptext,
-                markers=(_markers.Positional,)
+                markers=(_markers.Positional, _markers._PositionalCall)
                 if param.kind is inspect.Parameter.POSITIONAL_ONLY
                 else (),
             )

tyro/conf/_markers.py

@@ -18,6 +18,10 @@
 """A type `T` can be annotated as `Positional[T]` if we want to parse it as a positional
 argument."""
 
+# Private marker. For when an argument is not only positional in the CLI, but also in
+# the callable.
+_PositionalCall = Annotated[T, None]
+
 # TODO: the verb tenses here are inconsistent, naming could be revisited.
 # Perhaps Suppress should be Suppressed? But SuppressedFixed would be weird.