Bugfix ModelCreator for required model parameters and user adjusted model parameters (#2780)

Holzhauer · web-flow · commit 2e6ab85dc8cb · 2025-05-17T08:23:28.000-04:00
* bugfix _check_model_params in ModelCreator

* undo debug info in error message
diff --git a/mesa/visualization/solara_viz.py b/mesa/visualization/solara_viz.py
@@ -553,18 +553,18 @@ def ModelCreator(
     model_parameters = solara.use_reactive(model_parameters)
 
     solara.use_effect(
-        lambda: _check_model_params(model.value.__class__.__init__, fixed_params),
+        lambda: _check_model_params(model.value.__class__.__init__, user_params),
         [model.value],
     )
-    user_params, fixed_params = split_model_params(user_params)
+    user_adjust_params, fixed_params = split_model_params(user_params)
 
     # Use solara.use_effect to run the initialization code only once
     solara.use_effect(
         # set model_parameters to the default values for all parameters
         lambda: model_parameters.set(
             {
                 **fixed_params,
-                **{k: v.get("value") for k, v in user_params.items()},
+                **{k: v.get("value") for k, v in user_adjust_params.items()},
             }
         ),
         [],
@@ -574,7 +574,7 @@ def ModelCreator(
     def on_change(name, value):
         model_parameters.value = {**model_parameters.value, name: value}
 
-    UserInputs(user_params, on_change=on_change)
+    UserInputs(user_adjust_params, on_change=on_change)
 
 
 def _check_model_params(init_func, model_params):
diff --git a/tests/test_solara_viz.py b/tests/test_solara_viz.py
@@ -13,6 +13,7 @@
 from mesa.visualization.components.altair_components import make_altair_space
 from mesa.visualization.components.matplotlib_components import make_mpl_space_component
 from mesa.visualization.solara_viz import (
+    ModelCreator,
     Slider,
     SolaraViz,
     UserInputs,
@@ -273,6 +274,36 @@ def __init__(self, **kwargs):
         _check_model_params(ModelWithOnlyRequired.__init__, {})
 
 
+def test_model_creator():  # noqa: D103
+    class ModelWithRequiredParam:
+        def __init__(self, param1):
+            pass
+
+    solara.render(
+        ModelCreator(
+            solara.reactive(ModelWithRequiredParam(param1="mock")),
+            user_params={"param1": 1},
+        ),
+        handle_error=False,
+    )
+
+    solara.render(
+        ModelCreator(
+            solara.reactive(ModelWithRequiredParam(param1="mock")),
+            user_params={"param1": Slider("Param1", 10, 10, 100, 1)},
+        ),
+        handle_error=False,
+    )
+
+    with pytest.raises(ValueError, match="Missing required model parameter"):
+        solara.render(
+            ModelCreator(
+                solara.reactive(ModelWithRequiredParam(param1="mock")), user_params={}
+            ),
+            handle_error=False,
+        )
+
+
 # test that _check_model_params raises ValueError when *args are present
 def test_check_model_params_with_args_only():
     """Test that _check_model_params raises ValueError when *args are present."""
