Add support for forward references

pyproject.toml

@@ -38,7 +38,7 @@ Documentation = "https://typer.tiangolo.com/"
 [tool.flit.metadata.requires-extra]
 test = [
     "shellingham",
-    "pytest >=4.4.0",
+    "pytest >=4.4.0,< 5.4",
     "pytest-cov",
     "coverage",
     "pytest-xdist",

tests/test_others.py

@@ -199,3 +199,26 @@ def main(name: str = typer.Option(..., autocompletion=name_callback)):
     with pytest.raises(click.ClickException) as exc_info:
         runner.invoke(app, ["--name", "Camila"])
     assert exc_info.value.message == "Invalid autocompletion callback parameters: val2"
+
+
+def test_forward_references():
+    app = typer.Typer()
+
+    @app.command()
+    def main(arg1, arg2: int, arg3: "int", arg4: bool = False, arg5: "bool" = False):
+        typer.echo(f"arg1: {type(arg1)} {arg1}")
+        typer.echo(f"arg2: {type(arg2)} {arg2}")
+        typer.echo(f"arg3: {type(arg3)} {arg3}")
+        typer.echo(f"arg4: {type(arg4)} {arg4}")
+        typer.echo(f"arg5: {type(arg5)} {arg5}")
+
+    result = runner.invoke(app, ["Hello", "2", "invalid"])
+    assert (
+        "Error: Invalid value for 'ARG3': invalid is not a valid integer"
+        in result.stdout
+    )
+    result = runner.invoke(app, ["Hello", "2", "3", "--arg4", "--arg5"])
+    assert (
+        "arg1: <class 'str'> Hello\narg2: <class 'int'> 2\narg3: <class 'int'> 3\narg4: <class 'bool'> True\narg5: <class 'bool'> True\n"
+        in result.stdout
+    )

typer/completion.py

@@ -1,4 +1,3 @@
-import inspect
 import os
 import re
 import subprocess
@@ -10,7 +9,9 @@
 import click
 import click._bashcomplete
 
+from .models import ParamMeta
 from .params import Option
+from .utils import get_params_from_function
 
 try:
     import shellingham
@@ -21,14 +22,16 @@
 _click_patched = False
 
 
-def get_completion_inspect_parameters() -> Tuple[inspect.Parameter, inspect.Parameter]:
+def get_completion_inspect_parameters() -> Tuple[ParamMeta, ParamMeta]:
     completion_init()
     test_disable_detection = os.getenv("_TYPER_COMPLETE_TEST_DISABLE_SHELL_DETECTION")
     if shellingham and not test_disable_detection:
-        signature = inspect.signature(_install_completion_placeholder_function)
+        parameters = get_params_from_function(_install_completion_placeholder_function)
     else:
-        signature = inspect.signature(_install_completion_no_auto_placeholder_function)
-    install_param, show_param = signature.parameters.values()
+        parameters = get_params_from_function(
+            _install_completion_no_auto_placeholder_function
+        )
+    install_param, show_param = parameters.values()
     return install_param, show_param
 
 
@@ -204,7 +207,7 @@ def install_bash(*, prog_name: str, complete_var: str, shell: str) -> Path:
         rc_content = rc_path.read_text()
     completion_init_lines = [f"source {completion_path}"]
     for line in completion_init_lines:
-        if line not in rc_content:
+        if line not in rc_content:  # pragma: nocover
             rc_content += f"\n{line}"
     rc_content += "\n"
     rc_path.write_text(rc_content)
@@ -231,7 +234,7 @@ def install_zsh(*, prog_name: str, complete_var: str, shell: str) -> Path:
         "fpath+=~/.zfunc",
     ]
     for line in completion_init_lines:
-        if line not in zshrc_content:
+        if line not in zshrc_content:  # pragma: nocover
             zshrc_content += f"\n{line}"
     zshrc_content += "\n"
     zshrc_path.write_text(zshrc_content)

typer/main.py

@@ -23,9 +23,11 @@
     NoneType,
     OptionInfo,
     ParameterInfo,
+    ParamMeta,
     Required,
     TyperInfo,
 )
+from .utils import get_params_from_function
 
 
 def get_install_completion_arguments() -> Tuple[click.Parameter, click.Parameter]:
@@ -393,8 +395,8 @@ def get_params_convertors_ctx_param_name_from_function(
     convertors = {}
     context_param_name = None
     if callback:
-        signature = inspect.signature(callback)
-        for param_name, param in signature.parameters.items():
+        parameters = get_params_from_function(callback)
+        for param_name, param in parameters.items():
             if lenient_issubclass(param.annotation, click.Context):
                 context_param_name = param_name
                 continue
@@ -476,9 +478,9 @@ def get_callback(
 ) -> Optional[Callable]:
     if not callback:
         return None
-    signature = inspect.signature(callback)
+    parameters = get_params_from_function(callback)
     use_params: Dict[str, Any] = {}
-    for param_name, param_sig in signature.parameters.items():
+    for param_name in parameters:
         use_params[param_name] = None
     for param in params:
         use_params[param.name] = param.default
@@ -591,7 +593,7 @@ def lenient_issubclass(
 
 
 def get_click_param(
-    param: inspect.Parameter,
+    param: ParamMeta,
 ) -> Tuple[Union[click.Argument, click.Option], Any]:
     # First, find out what will be:
     # * ParamInfo (ArgumentInfo or OptionInfo)
@@ -744,12 +746,12 @@ def get_param_callback(
 ) -> Optional[Callable]:
     if not callback:
         return None
-    signature = inspect.signature(callback)
+    parameters = get_params_from_function(callback)
     ctx_name = None
     click_param_name = None
     value_name = None
     untyped_names: List[str] = []
-    for param_name, param_sig in signature.parameters.items():
+    for param_name, param_sig in parameters.items():
         if lenient_issubclass(param_sig.annotation, click.Context):
             ctx_name = param_name
         elif lenient_issubclass(param_sig.annotation, click.Parameter):
@@ -792,11 +794,11 @@ def wrapper(ctx: click.Context, param: click.Parameter, value: Any) -> Any:
 def get_param_completion(callback: Optional[Callable] = None) -> Optional[Callable]:
     if not callback:
         return None
-    signature = inspect.signature(callback)
+    parameters = get_params_from_function(callback)
     ctx_name = None
     args_name = None
     incomplete_name = None
-    unassigned_params = [param for param in signature.parameters.values()]
+    unassigned_params = [param for param in parameters.values()]
     for param_sig in unassigned_params[:]:
         origin = getattr(param_sig.annotation, "__origin__", None)
         if lenient_issubclass(param_sig.annotation, click.Context):

typer/models.py

@@ -1,3 +1,4 @@
+import inspect
 import io
 from typing import (
     TYPE_CHECKING,
@@ -388,3 +389,18 @@ def __init__(
             allow_dash=allow_dash,
             path_type=path_type,
         )
+
+
+class ParamMeta:
+    empty = inspect.Parameter.empty
+
+    def __init__(
+        self,
+        *,
+        name: str,
+        default: Any = inspect.Parameter.empty,
+        annotation: Any = inspect.Parameter.empty,
+    ) -> None:
+        self.name = name
+        self.default = default
+        self.annotation = annotation

typer/utils.py

@@ -0,0 +1,18 @@
+import inspect
+from typing import Callable, Dict, get_type_hints
+
+from .models import ParamMeta
+
+
+def get_params_from_function(func: Callable) -> Dict[str, ParamMeta]:
+    signature = inspect.signature(func)
+    type_hints = get_type_hints(func)
+    params = {}
+    for param in signature.parameters.values():
+        annotation = param.annotation
+        if param.name in type_hints:
+            annotation = type_hints[param.name]
+        params[param.name] = ParamMeta(
+            name=param.name, default=param.default, annotation=annotation
+        )
+    return params