Enable option to raise excpetion if magicgui cannot determine widget …

…for provided value/annotation (#476)

* initial implementation

* add tests

* add argument to magic factory

magicgui/_magicgui.py

@@ -25,6 +25,7 @@ def magicgui(
     main_window: bool = False,
     app: AppRef = None,
     persist: bool = False,
+    raise_on_unknown: bool = False,
     **param_options: dict,
 ):
     """Return a :class:`FunctionGui` for ``function``.
@@ -65,6 +66,9 @@ def magicgui(
         disk and restored when the widget is loaded again with ``persist = True``.
         Call ``magicgui._util.user_cache_dir()`` to get the default cache location.
         By default False.
+    raise_on_unknown : bool, optional
+        If ``True``, raise an error if magicgui cannot determine widget for function
+        argument or return type. If ``False``, ignore unknown types. By default False.
 
     **param_options : dict of dict
         Any additional keyword arguments will be used as parameter-specific options.
@@ -108,6 +112,7 @@ def magic_factory(
     app: AppRef = None,
     persist: bool = False,
     widget_init: Callable[[FunctionGui], None] | None = None,
+    raise_on_unknown: bool = False,
     **param_options: dict,
 ):
     """Return a :class:`MagicFactory` for ``function``."""

magicgui/_magicgui.pyi

@@ -35,6 +35,7 @@ def magicgui(  # noqa
     main_window: Literal[False] = False,
     app: AppRef = None,
     persist: bool = False,
+    raise_on_unknown: bool = False,
     **param_options: dict,
 ) -> FunctionGui[_R]: ...
 @overload  # noqa: E302
@@ -51,6 +52,7 @@ def magicgui(  # noqa
     main_window: Literal[False] = False,
     app: AppRef = None,
     persist: bool = False,
+    raise_on_unknown: bool = False,
     **param_options: dict,
 ) -> Callable[[Callable[..., _R]], FunctionGui[_R]]: ...
 @overload  # noqa: E302
@@ -67,6 +69,7 @@ def magicgui(  # noqa
     main_window: Literal[True],
     app: AppRef = None,
     persist: bool = False,
+    raise_on_unknown: bool = False,
     **param_options: dict,
 ) -> MainFunctionGui[_R]: ...
 @overload  # noqa: E302
@@ -83,6 +86,7 @@ def magicgui(  # noqa
     main_window: Literal[True],
     app: AppRef = None,
     persist: bool = False,
+    raise_on_unknown: bool = False,
     **param_options: dict,
 ) -> Callable[[Callable[..., _R]], MainFunctionGui[_R]]: ...
 @overload  # noqa: E302
@@ -100,6 +104,7 @@ def magic_factory(  # noqa
     app: AppRef = None,
     persist: bool = False,
     widget_init: Callable[[FunctionGui], None] | None = None,
+    raise_on_unknown: bool = False,
     **param_options: dict,
 ) -> MagicFactory[FunctionGui[_R]]: ...
 @overload  # noqa: E302
@@ -117,6 +122,7 @@ def magic_factory(  # noqa
     app: AppRef = None,
     persist: bool = False,
     widget_init: Callable[[FunctionGui], None] | None = None,
+    raise_on_unknown: bool = False,
     **param_options: dict,
 ) -> Callable[[Callable[..., _R]], MagicFactory[FunctionGui[_R]]]: ...
 @overload  # noqa: E302
@@ -134,6 +140,7 @@ def magic_factory(  # noqa
     app: AppRef = None,
     persist: bool = False,
     widget_init: Callable[[FunctionGui], None] | None = None,
+    raise_on_unknown: bool = False,
     **param_options: dict,
 ) -> MagicFactory[MainFunctionGui[_R]]: ...
 @overload  # noqa: E302
@@ -151,5 +158,6 @@ def magic_factory(  # noqa
     app: AppRef = None,
     persist: bool = False,
     widget_init: Callable[[FunctionGui], None] | None = None,
+    raise_on_unknown: bool = False,
     **param_options: dict,
 ) -> Callable[[Callable[..., _R]], MagicFactory[MainFunctionGui[_R]]]: ...

magicgui/signature.py

@@ -107,9 +107,11 @@ def __init__(
         default: Any = inspect.Parameter.empty,
         annotation: Any = inspect.Parameter.empty,
         gui_options: dict = None,
+        raise_on_unknown: bool = False,
     ):
         _annotation = make_annotated(annotation, gui_options)
         super().__init__(name, kind, default=default, annotation=_annotation)
+        self.raise_on_unknown = raise_on_unknown
 
     @property
     def options(self) -> WidgetOptions:
@@ -118,7 +120,7 @@ def options(self) -> WidgetOptions:
 
     def __repr__(self) -> str:
         """Return __repr__, replacing NoneType if present."""
-        rep = super().__repr__()[:-1] + f" {self.options}>"
+        rep = f"{super().__repr__()[:-1]} {self.options}>"
         rep = rep.replace(": NoneType = ", "=")
         return rep
 
@@ -144,6 +146,7 @@ def to_widget(self, app: AppRef = None) -> Widget:
             annotation=annotation,
             app=app,
             options=options,
+            raise_on_unknown=self.raise_on_unknown,
         )
         widget.param_kind = self.kind
         return widget
@@ -161,7 +164,10 @@ def from_widget(cls, widget: Widget) -> MagicParameter:
 
     @classmethod
     def from_parameter(
-        cls, param: inspect.Parameter, gui_options: dict = None
+        cls,
+        param: inspect.Parameter,
+        gui_options: dict = None,
+        raise_on_unknown: bool = False,
     ) -> MagicParameter:
         """Create MagicParameter from an inspect.Parameter."""
         if isinstance(param, MagicParameter):
@@ -172,6 +178,7 @@ def from_parameter(
             default=param.default,
             annotation=param.annotation,
             gui_options=gui_options,
+            raise_on_unknown=raise_on_unknown,
         )
 
 
@@ -198,15 +205,20 @@ def __init__(
         *,
         return_annotation=inspect.Signature.empty,
         gui_options: dict[str, dict] = None,
+        raise_on_unknown: bool = False,
     ):
         params = [
-            MagicParameter.from_parameter(p, (gui_options or {}).get(p.name))
+            MagicParameter.from_parameter(
+                p, (gui_options or {}).get(p.name), raise_on_unknown
+            )
             for p in parameters or []
         ]
         super().__init__(params, return_annotation=return_annotation)
 
     @classmethod
-    def from_signature(cls, sig: inspect.Signature, gui_options=None) -> MagicSignature:
+    def from_signature(
+        cls, sig: inspect.Signature, gui_options=None, raise_on_unknown=False
+    ) -> MagicSignature:
         """Convert regular inspect.Signature to MagicSignature."""
         if type(sig) is cls:
             return cast(MagicSignature, sig)
@@ -216,6 +228,7 @@ def from_signature(cls, sig: inspect.Signature, gui_options=None) -> MagicSignat
             list(sig.parameters.values()),
             return_annotation=sig.return_annotation,
             gui_options=gui_options,
+            raise_on_unknown=raise_on_unknown,
         )
 
     def widgets(self, app: AppRef = None) -> MappingProxyType:
@@ -254,7 +267,11 @@ def replace(
 
 
 def magic_signature(
-    obj: Callable, *, gui_options: dict[str, dict] = None, follow_wrapped: bool = True
+    obj: Callable,
+    *,
+    gui_options: dict[str, dict] = None,
+    follow_wrapped: bool = True,
+    raise_on_unknown: bool = False,
 ) -> MagicSignature:
     """Create a MagicSignature from a callable object.
 
@@ -270,6 +287,8 @@ def magic_signature(
         Will be passed to `MagicSignature.from_signature` by default None
     follow_wrapped : bool, optional
         passed to inspect.signature, by default True
+    raise_on_unknown : bool, optional
+        If True, raise an error if a parameter annotation is not recognized.
 
     Returns
     -------
@@ -297,4 +316,6 @@ def magic_signature(
             s = "s" if len(bad) > 1 else ""
             raise TypeError(f"Value for parameter{s} {bad} must be a dict")
 
-    return MagicSignature.from_signature(sig, gui_options=gui_options)
+    return MagicSignature.from_signature(
+        sig, gui_options=gui_options, raise_on_unknown=raise_on_unknown
+    )

magicgui/type_map.py

@@ -155,6 +155,7 @@ def pick_widget_type(
     annotation: type[Any] | None = None,
     options: WidgetOptions | None = None,
     is_result: bool = False,
+    raise_on_unknown: bool = True,
 ) -> WidgetTuple:
     """Pick the appropriate widget type for ``value`` with ``annotation``."""
     if is_result and annotation is inspect.Parameter.empty:
@@ -208,6 +209,11 @@ def pick_widget_type(
         _cls, opts = _widget_type
         return _cls, {**options, **opts}  # type: ignore
 
+    if raise_on_unknown:
+        raise ValueError(
+            f"No widget found for type {_type} and annotation {annotation}"
+        )
+
     return widgets.EmptyWidget, {"visible": False}
 
 
@@ -216,6 +222,7 @@ def get_widget_class(
     annotation: type[Any] | None = None,
     options: WidgetOptions | None = None,
     is_result: bool = False,
+    raise_on_unknown: bool = True,
 ) -> tuple[WidgetClass, WidgetOptions]:
     """Return a WidgetClass appropriate for the given parameters.
 
@@ -231,6 +238,8 @@ def get_widget_class(
     is_result : bool, optional
         Identifies whether the returned widget should be tailored to
         an input or to an output.
+    raise_on_unknown : bool, optional
+        Raise exception if no widget is found for the given type, by default True
 
     Returns
     -------
@@ -240,7 +249,9 @@ def get_widget_class(
     """
     _options = cast(WidgetOptions, options)
 
-    widget_type, _options = pick_widget_type(value, annotation, _options, is_result)
+    widget_type, _options = pick_widget_type(
+        value, annotation, _options, is_result, raise_on_unknown
+    )
 
     if isinstance(widget_type, str):
         widget_class: WidgetClass = _import_class(widget_type)

magicgui/widgets/_bases/create_widget.py

@@ -23,6 +23,7 @@ def create_widget(
     widget_type: str | type[_protocols.WidgetProtocol] | None = None,
     options: WidgetOptions = dict(),
     is_result: bool = False,
+    raise_on_unknown: bool = True,
 ):
     """Create and return appropriate widget subclass.
 
@@ -62,6 +63,8 @@ def create_widget(
     is_result : boolean, optional
         Whether the widget belongs to an input or an output. By defult, an input
         is assumed.
+     raise_on_unknown : bool, optional
+        Raise exception if no widget is found for the given type, by default True
 
     Returns
     -------
@@ -77,6 +80,7 @@ def create_widget(
     options = options.copy()
     kwargs = locals().copy()
     _kind = kwargs.pop("param_kind", None)
+    kwargs.pop("raise_on_unknown")
     _is_result = kwargs.pop("is_result", None)
     _app = use_app(kwargs.pop("app"))
     assert _app.native
@@ -87,7 +91,9 @@ def create_widget(
 
         if widget_type:
             options["widget_type"] = widget_type
-        wdg_class, opts = get_widget_class(value, annotation, options, is_result)
+        wdg_class, opts = get_widget_class(
+            value, annotation, options, is_result, raise_on_unknown
+        )
 
         if issubclass(wdg_class, Widget):
             opts.update(kwargs.pop("options"))

magicgui/widgets/_function_gui.py

@@ -136,6 +136,7 @@ def __init__(
         param_options: dict[str, dict] | None = None,
         name: str = None,
         persist: bool = False,
+        raise_on_unknown=False,
         **kwargs,
     ):
         if not callable(function):
@@ -151,7 +152,9 @@ def __init__(
         elif not isinstance(param_options, dict):
             raise TypeError("'param_options' must be a dict of dicts")
 
-        sig = magic_signature(function, gui_options=param_options)
+        sig = magic_signature(
+            function, gui_options=param_options, raise_on_unknown=raise_on_unknown
+        )
         self.return_annotation = sig.return_annotation
         self._tooltips = tooltips
         if tooltips:
@@ -221,6 +224,7 @@ def _disable_button_and_call():
                 annotation=self._return_annotation,
                 gui_only=True,
                 is_result=True,
+                raise_on_unknown=raise_on_unknown,
             )
             self.append(self._result_widget)
 

tests/test_magicgui.py

@@ -373,7 +373,7 @@ def get_layout_items(gui):
 
     gui = magicgui(func, labels=labels)
     assert get_layout_items(gui) == ["a", "b", "c", "call_button"]
-    gui.insert(1, widgets.create_widget(name="new"))
+    gui.insert(1, widgets.create_widget(name="new", raise_on_unknown=False))
     assert get_layout_items(gui) == ["a", "new", "b", "c", "call_button"]
 
 
@@ -842,3 +842,31 @@ def test_nonscrollable(a: int = 1, y: str = "a"):
 
     assert test_nonscrollable.native is test_nonscrollable.root_native_widget
     assert not isinstance(test_nonscrollable.native, QScrollArea)
+
+
+def test_unknown_exception_magicgui():
+    """Test that an unknown type is raised as a RuntimeError."""
+
+    class A:
+        pass
+
+    with pytest.raises(ValueError, match="No widget found for type"):
+
+        @magicgui(raise_on_unknown=True)
+        def func(a: A):
+            print(a)
+
+
+def test_unknown_exception_create_widget():
+    """Test that an unknown type is raised as a RuntimeError."""
+
+    class A:
+        pass
+
+    with pytest.raises(ValueError, match="No widget found for type"):
+        widgets.create_widget(A, raise_on_unknown=True)
+    with pytest.raises(ValueError, match="No widget found for type"):
+        widgets.create_widget(A)
+    assert isinstance(
+        widgets.create_widget(A, raise_on_unknown=False), widgets.EmptyWidget
+    )