🐛 Fix support for UnionType (e.g. str | None) with Python 3.11 (#548

)

Co-authored-by: svlandeg <svlandeg@github.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

tests/test_type_conversion.py

@@ -7,6 +7,8 @@
 import typer
 from typer.testing import CliRunner
 
+from .utils import needs_py310
+
 runner = CliRunner()
 
 
@@ -29,6 +31,26 @@ def opt(user: Optional[str] = None):
     assert "User: Camila" in result.output
 
 
+@needs_py310
+def test_union_type_optional():
+    app = typer.Typer()
+
+    @app.command()
+    def opt(user: str | None = None):
+        if user:
+            print(f"User: {user}")
+        else:
+            print("No user")
+
+    result = runner.invoke(app)
+    assert result.exit_code == 0
+    assert "No user" in result.output
+
+    result = runner.invoke(app, ["--user", "Camila"])
+    assert result.exit_code == 0
+    assert "User: Camila" in result.output
+
+
 def test_optional_tuple():
     app = typer.Typer()
 

typer/main.py

@@ -13,6 +13,7 @@
 
 import click
 
+from ._typing import get_args, get_origin, is_union
 from .completion import get_completion_inspect_parameters
 from .core import MarkupMode, TyperArgument, TyperCommand, TyperGroup, TyperOption
 from .models import (
@@ -825,30 +826,31 @@ def get_click_param(
     is_tuple = False
     parameter_type: Any = None
     is_flag = None
-    origin = getattr(main_type, "__origin__", None)
+    origin = get_origin(main_type)
+
     if origin is not None:
-        # Handle Optional[SomeType]
-        if origin is Union:
+        # Handle SomeType | None and Optional[SomeType]
+        if is_union(origin):
             types = []
-            for type_ in main_type.__args__:
+            for type_ in get_args(main_type):
                 if type_ is NoneType:
                     continue
                 types.append(type_)
             assert len(types) == 1, "Typer Currently doesn't support Union types"
             main_type = types[0]
-            origin = getattr(main_type, "__origin__", None)
+            origin = get_origin(main_type)
         # Handle Tuples and Lists
         if lenient_issubclass(origin, List):
-            main_type = main_type.__args__[0]
-            assert not getattr(
-                main_type, "__origin__", None
+            main_type = get_args(main_type)[0]
+            assert not get_origin(
+                main_type
             ), "List types with complex sub-types are not currently supported"
             is_list = True
         elif lenient_issubclass(origin, Tuple):  # type: ignore
             types = []
-            for type_ in main_type.__args__:
-                assert not getattr(
-                    type_, "__origin__", None
+            for type_ in get_args(main_type):
+                assert not get_origin(
+                    type_
                 ), "Tuple types with complex sub-types are not currently supported"
                 types.append(
                     get_click_type(annotation=type_, parameter_info=parameter_info)
@@ -865,7 +867,7 @@ def get_click_param(
             convertor=convertor, default_value=default_value
         )
     if is_tuple:
-        convertor = generate_tuple_convertor(main_type.__args__)
+        convertor = generate_tuple_convertor(get_args(main_type))
     if isinstance(parameter_info, OptionInfo):
         if main_type is bool and parameter_info.is_flag is not False:
             is_flag = True
@@ -1020,7 +1022,7 @@ def get_param_completion(
     incomplete_name = None
     unassigned_params = list(parameters.values())
     for param_sig in unassigned_params[:]:
-        origin = getattr(param_sig.annotation, "__origin__", None)
+        origin = get_origin(param_sig.annotation)
         if lenient_issubclass(param_sig.annotation, click.Context):
             ctx_name = param_sig.name
             unassigned_params.remove(param_sig)