✨ Add support for typing.TypeAliasType as valid parameter type.

pyproject.toml

@@ -36,7 +36,7 @@ classifiers = [
 ]
 dependencies = [
     "click >= 8.0.0",
-    "typing-extensions >= 3.7.4.3",
+    "typing-extensions >= 4.6.0",
 ]
 readme = "README.md"
 [project.urls]

tests/test_main.py

@@ -0,0 +1,139 @@
+from datetime import datetime
+from enum import Enum
+from pathlib import Path
+from uuid import UUID
+
+import click
+import pytest
+from typer._typing import TypeAliasType
+from typer.main import get_click_type
+from typer.models import FileBinaryRead, FileTextWrite, ParameterInfo
+
+
+def test_get_click_type_with_custom_click_type():
+    custom_click_type = click.INT
+    param_info = ParameterInfo(click_type=custom_click_type)
+    result = get_click_type(annotation=int, parameter_info=param_info)
+    assert result is custom_click_type
+
+
+def test_get_click_type_with_custom_parser():
+    def mock_parser(x):
+        return 42
+
+    param_info = ParameterInfo(parser=mock_parser)
+    result = get_click_type(annotation=int, parameter_info=param_info)
+    assert isinstance(result, click.types.FuncParamType)
+    assert result.convert("42", None, None) == 42
+
+
+def test_get_click_type_with_str_annotation():
+    param_info = ParameterInfo()
+    result = get_click_type(annotation=str, parameter_info=param_info)
+    assert result is click.STRING
+
+
+def test_get_click_type_with_int_annotation_no_min_max():
+    param_info = ParameterInfo()
+    result = get_click_type(annotation=int, parameter_info=param_info)
+    assert result is click.INT
+
+
+def test_get_click_type_with_int_annotation_with_min_max():
+    param_info = ParameterInfo(min=10, max=100)
+    result = get_click_type(annotation=int, parameter_info=param_info)
+    assert isinstance(result, click.IntRange)
+    assert result.min == 10
+    assert result.max == 100
+
+
+def test_get_click_type_with_float_annotation_no_min_max():
+    param_info = ParameterInfo()
+    result = get_click_type(annotation=float, parameter_info=param_info)
+    assert result is click.FLOAT
+
+
+def test_get_click_type_with_float_annotation_with_min_max():
+    param_info = ParameterInfo(min=0.1, max=10.5)
+    result = get_click_type(annotation=float, parameter_info=param_info)
+    assert isinstance(result, click.FloatRange)
+    assert result.min == 0.1
+    assert result.max == 10.5
+
+
+def test_get_click_type_with_bool_annotation():
+    param_info = ParameterInfo()
+    result = get_click_type(annotation=bool, parameter_info=param_info)
+    assert result is click.BOOL
+
+
+def test_get_click_type_with_uuid_annotation():
+    param_info = ParameterInfo()
+    result = get_click_type(annotation=UUID, parameter_info=param_info)
+    assert result is click.UUID
+
+
+def test_get_click_type_with_datetime_annotation():
+    param_info = ParameterInfo(formats=["%Y-%m-%d"])
+    result = get_click_type(annotation=datetime, parameter_info=param_info)
+    assert isinstance(result, click.DateTime)
+    assert result.formats == ["%Y-%m-%d"]
+
+
+def test_get_click_type_with_path_annotation():
+    param_info = ParameterInfo(resolve_path=True)
+    result = get_click_type(annotation=Path, parameter_info=param_info)
+    assert isinstance(result, click.Path)
+    assert result.resolve_path is True
+
+
+def test_get_click_type_with_enum_annotation():
+    class Color(Enum):
+        RED = "red"
+        BLUE = "blue"
+
+    param_info = ParameterInfo()
+    result = get_click_type(annotation=Color, parameter_info=param_info)
+    assert isinstance(result, click.Choice)
+    assert result.choices == ("red", "blue")
+
+
+def test_get_click_type_with_file_text_write_annotation():
+    param_info = ParameterInfo(mode="w", encoding="utf-8")
+    result = get_click_type(annotation=FileTextWrite, parameter_info=param_info)
+    assert isinstance(result, click.File)
+    assert result.mode == "w"
+    assert result.encoding == "utf-8"
+
+
+def test_get_click_type_with_file_binary_read_annotation():
+    param_info = ParameterInfo(mode="rb")
+    result = get_click_type(annotation=FileBinaryRead, parameter_info=param_info)
+    assert isinstance(result, click.File)
+    assert result.mode == "rb"
+
+
+def test_get_click_type_with_type_alias_type():
+    # define TypeAliasType
+    Name = TypeAliasType(name="Name", value=str)
+    Surname = TypeAliasType(name="Surname", value=Name)
+
+    param_info = ParameterInfo()
+    result = get_click_type(annotation=Name, parameter_info=param_info)
+    assert result is click.STRING
+
+    # recursive types
+    param_info = ParameterInfo()
+    result = get_click_type(annotation=Surname, parameter_info=param_info)
+    assert result is click.STRING
+
+
+def test_get_click_type_with_unsupported_type():
+    class UnsupportedType:
+        pass
+
+    param_info = ParameterInfo()
+    with pytest.raises(
+        RuntimeError, match="Type not yet supported: <class '.*UnsupportedType.*'>"
+    ):
+        get_click_type(annotation=UnsupportedType, parameter_info=param_info)

typer/_typing.py

@@ -36,6 +36,11 @@ def is_union(tp: Optional[Type[Any]]) -> bool:
         return tp is Union or tp is types.UnionType  # noqa: E721
 
 
+if sys.version_info < (3, 12):
+    from typing_extensions import TypeAliasType, TypeVar
+else:
+    from typing import TypeAliasType, TypeVar
+
 __all__ = (
     "NoneType",
     "is_none_type",
@@ -45,6 +50,8 @@ def is_union(tp: Optional[Type[Any]]) -> bool:
     "is_union",
     "Annotated",
     "Literal",
+    "TypeAliasType",
+    "TypeVar",
     "get_args",
     "get_origin",
     "get_type_hints",

typer/main.py

@@ -11,13 +11,30 @@
 from pathlib import Path
 from traceback import FrameSummary, StackSummary
 from types import TracebackType
-from typing import Any, Callable, Dict, List, Optional, Sequence, Tuple, Type, Union
+from typing import (
+    Any,
+    Callable,
+    Dict,
+    List,
+    Optional,
+    Sequence,
+    Tuple,
+    Type,
+    Union,
+)
 from uuid import UUID
 
 import click
 from typer._types import TyperChoice
 
-from ._typing import get_args, get_origin, is_literal_type, is_union, literal_values
+from ._typing import (
+    TypeAliasType,
+    get_args,
+    get_origin,
+    is_literal_type,
+    is_union,
+    literal_values,
+)
 from .completion import get_completion_inspect_parameters
 from .core import (
     DEFAULT_MARKUP_MODE,
@@ -48,7 +65,7 @@
     TyperInfo,
     TyperPath,
 )
-from .utils import get_params_from_function
+from .utils import get_original_type, get_params_from_function
 
 _original_except_hook = sys.excepthook
 _typer_developer_exception_attr_name = "__typer_developer_exception__"
@@ -697,6 +714,9 @@ def wrapper(**kwargs: Any) -> Any:
 def get_click_type(
     *, annotation: Any, parameter_info: ParameterInfo
 ) -> click.ParamType:
+    if isinstance(annotation, TypeAliasType):
+        annotation = get_original_type(annotation)
+
     if parameter_info.click_type is not None:
         return parameter_info.click_type
 

typer/utils.py

@@ -3,9 +3,19 @@
 from copy import copy
 from typing import Any, Callable, Dict, List, Tuple, Type, cast
 
-from ._typing import Annotated, get_args, get_origin, get_type_hints
+from ._typing import (
+    Annotated,
+    TypeAliasType,
+    TypeVar,
+    get_args,
+    get_origin,
+    get_type_hints,
+)
 from .models import ArgumentInfo, OptionInfo, ParameterInfo, ParamMeta
 
+T = TypeVar("T")
+TypeAliasTypeVar = TypeAliasType("TypeAliasTypeVar", value=T, type_params=(T,))
+
 
 def _param_type_to_user_string(param_type: Type[ParameterInfo]) -> str:
     # Render a `ParameterInfo` subclass for use in error messages.
@@ -188,3 +198,24 @@ def get_params_from_function(func: Callable[..., Any]) -> Dict[str, ParamMeta]:
             name=param.name, default=default, annotation=annotation
         )
     return params
+
+
+def get_original_type(alias: TypeAliasTypeVar[T]) -> T:
+    """Return the original type of an alias.
+
+    Examples
+    --------
+    >>> Name = TypeAliasType(name="Name", value=str)
+    >>> Surname = TypeAliasType(name="Surname", value=Name)
+    >>> get_original_type(Name)
+    str
+    >>> get_original_type(Surname)
+    str
+    >>> get_original_type(int)
+    int
+    """
+    otype = alias
+    while isinstance(otype, TypeAliasType):
+        otype = otype.__value__
+
+    return otype