mandatory attribute and typing for ToggleButtons

solara/components/togglebuttons.py

@@ -50,6 +50,36 @@ def ToggleButtonsSingle(
     ...
 
 
+@overload
+@solara.value_component(None)
+def ToggleButtonsSingle(
+    value: Union[T, solara.Reactive[T]],
+    values: List[T] = ...,
+    children: List[reacton.core.Element] = ...,
+    on_value: Optional[Callable[[T], None]] = ...,
+    dense: bool = ...,
+    mandatory: Literal[True] = ...,
+    classes: List[str] = ...,
+    style: Union[str, Dict[str, str], None] = ...,
+) -> reacton.core.ValueElement[v.BtnToggle, T]:
+    ...
+
+
+@overload
+@solara.value_component(None)
+def ToggleButtonsSingle(
+    value: Union[Optional[T], solara.Reactive[Optional[T]]] = None,
+    values: List[T] = ...,
+    children: List[reacton.core.Element] = ...,
+    on_value: Optional[Callable[[T], None]] = ...,
+    dense: bool = ...,
+    mandatory: Literal[False] = ...,
+    classes: List[str] = ...,
+    style: Union[str, Dict[str, str], None] = ...,
+) -> reacton.core.ValueElement[v.BtnToggle, T]:
+    ...
+
+
 @solara.value_component(None)
 def ToggleButtonsSingle(
     value: Union[None, T, Optional[T], solara.Reactive[T], solara.Reactive[Optional[T]]] = None,
@@ -123,6 +153,10 @@ def Page():
     # (see https://github.com/widgetti/solara/issues/282)
     # TODO: set index to 0 on python side (after #282 is resolved)
     index, set_index = solara.use_state_or_update(values.index(reactive_value.value) if reactive_value.value is not None else None, key="index")
+    # When mandatory = True, index should not be None, but we are letting the front-end take care of setting index to 0 because of a bug
+    # (see https://github.com/widgetti/solara/issues/282)
+    # TODO: set index to 0 on python side (after #282 is resolved)
+    index, set_index = solara.use_state_or_update(values.index(reactive_value.value) if reactive_value.value is not None else None, key="index")
 
     def on_index(index):
         set_index(index)
@@ -142,6 +176,7 @@ def on_index(index):
     )
 
 
+@overload
 @overload
 @solara.value_component(None)
 def ToggleButtonsMultiple(