typing.Annotated workaround for pydantic v1 (#187)

* Workaround for pydantic v1, which strips `typing.Annotated` metadata

* docstring_parser doesn't seem to work with Pydantic v1 + Python 3.8

* sys version check

src/tyro/_fields.py

@@ -674,6 +674,10 @@ def _field_list_from_pydantic(
             cls_cast = cast(pydantic_v1.BaseModel, cls)  # type: ignore
         else:
             cls_cast = cls
+
+        hints = _resolver.get_type_hints_with_backported_syntax(
+            cls, include_extras=True
+        )
         for pd1_field in cls_cast.__fields__.values():
             helptext = pd1_field.field_info.description
             if helptext is None:
@@ -686,7 +690,7 @@ def _field_list_from_pydantic(
             field_list.append(
                 FieldDefinition.make(
                     name=pd1_field.name,
-                    type_or_callable=pd1_field.outer_type_,
+                    type_or_callable=hints[pd1_field.name],
                     default=default,
                     is_default_from_default_instance=is_default_from_default_instance,
                     helptext=helptext,

tests/test_py311_generated/test_pydantic_generated.py

@@ -6,6 +6,7 @@
 from typing import Annotated, cast
 
 import pytest
+from helptext_utils import get_helptext_with_checks
 from pydantic import BaseModel, Field, v1
 
 import tyro
@@ -51,6 +52,32 @@ class ManyTypesA(v1.BaseModel):
     ) == ManyTypesA(i=5, s="hello", f=3.0, p=pathlib.Path("~"))
 
 
+def test_pydantic_v1_conf() -> None:
+    class ManyTypesA(v1.BaseModel):
+        i: int
+        """This is a docstring."""
+        s: tyro.conf.Suppress[str] = "hello"
+        f: float = v1.Field(default_factory=lambda: 3.0)
+
+    class ManyTypesB(ManyTypesA):
+        p: pathlib.Path
+
+    # We can directly pass a dataclass to `tyro.cli()`:
+    assert tyro.cli(
+        ManyTypesB,
+        args=[
+            "--i",
+            "5",
+            "--p",
+            "~",
+        ],
+    ) == ManyTypesB(i=5, s="hello", f=3.0, p=pathlib.Path("~"))
+    helptext = get_helptext_with_checks(ManyTypesB)
+    assert "--s" not in helptext
+    assert "--i" in helptext
+    assert "This is a docstring" in helptext
+
+
 def test_pydantic_helptext() -> None:
     class Helptext(BaseModel):
         """This docstring should be printed as a description."""

tests/test_pydantic.py

@@ -3,9 +3,11 @@
 import contextlib
 import io
 import pathlib
+import sys
 from typing import cast
 
 import pytest
+from helptext_utils import get_helptext_with_checks
 from pydantic import BaseModel, Field, v1
 from typing_extensions import Annotated
 
@@ -52,6 +54,37 @@ class ManyTypesA(v1.BaseModel):
     ) == ManyTypesA(i=5, s="hello", f=3.0, p=pathlib.Path("~"))
 
 
+def test_pydantic_v1_conf() -> None:
+    class ManyTypesA(v1.BaseModel):
+        i: int
+        """This is a docstring."""
+        s: tyro.conf.Suppress[str] = "hello"
+        f: float = v1.Field(default_factory=lambda: 3.0)
+
+    class ManyTypesB(ManyTypesA):
+        p: pathlib.Path
+
+    # We can directly pass a dataclass to `tyro.cli()`:
+    assert tyro.cli(
+        ManyTypesB,
+        args=[
+            "--i",
+            "5",
+            "--p",
+            "~",
+        ],
+    ) == ManyTypesB(i=5, s="hello", f=3.0, p=pathlib.Path("~"))
+    helptext = get_helptext_with_checks(ManyTypesB)
+    assert "--s" not in helptext
+    assert "--i" in helptext
+
+    # This doesn't work when combining older versions of Python with older
+    # versions of pydantic. The root cause may be in the docstring_parser
+    # dependency.
+    if sys.version_info >= (3, 10):
+        assert "This is a docstring" in helptext
+
+
 def test_pydantic_helptext() -> None:
     class Helptext(BaseModel):
         """This docstring should be printed as a description."""