Scope the nested input keys of a kwargs input to that input

front/elements/elements.py

@@ -630,7 +630,11 @@ class KwargsInputBase(InputBase):
     func_sig: Sig | Callable = None
 
     def pre_render(self):
-        """Make ``self.get_kwargs``, a function with signature ``func_sig`` returning its kwargs."""
+        """Make ``self.get_kwargs``, a function with signature ``func_sig`` returning its kwargs.
+
+        It is named after ``input_key``, so the nested inputs get keys like
+        ``<input_key>_<param>``.
+        """
         super().pre_render()
         func_sig = self.func_sig if isinstance(self.func_sig, Sig) else self.func_sig()
         func_sig = func_sig or Sig()
@@ -639,6 +643,10 @@ def pre_render(self):
         def get_kwargs(**kwargs):
             return kwargs
 
+        # The nested inputs' keys derive from this function's name (see
+        # ``mk_input_element_specs``): name it after this input so that they are
+        # scoped to it and do not collide across kwargs inputs (i2mint/front#40).
+        get_kwargs.__name__ = self.input_key or get_kwargs.__name__
         self.get_kwargs = get_kwargs
 
     def _return_kwargs(self, output):

tests/test_kwargs_input_keys.py

@@ -0,0 +1,40 @@
+"""The nested inputs of a kwargs input are keyed by that input, not by ``get_kwargs``.
+
+Regression test for i2mint/front#40: every parameter inside a ``KwargsInput`` used
+to get the key ``get_kwargs_<param>``, so two kwargs inputs sharing a parameter name
+shared their value, widget key and state.
+"""
+
+from dataclasses import dataclass
+from inspect import Parameter
+
+from i2 import Sig
+
+from front.data_binding import BoundData
+from front.elements.elements import KwargsInputBase, mk_input_element_specs
+
+
+@dataclass
+class _Kwargs(KwargsInputBase):
+    def render(self):
+        return None
+
+
+def _nested_input_keys(input_key, state):
+    kwargs_input = _Kwargs(
+        obj=Parameter("kwargs", Parameter.VAR_KEYWORD),
+        input_key=input_key,
+        func_sig=Sig("data"),
+        bound_data_factory=lambda k: BoundData(k, state),
+    )
+    kwargs_input.pre_render()
+    specs = mk_input_element_specs(kwargs_input.get_kwargs, {})
+    return {name: spec["input_key"] for name, spec in specs.items()}
+
+
+def test_nested_input_keys_are_scoped_to_the_kwargs_input():
+    state = {}
+    first = _nested_input_keys("foo_kwargs", state)
+    second = _nested_input_keys("bar_kwargs", state)
+    assert first == {"data": "foo_kwargs_data"}
+    assert second == {"data": "bar_kwargs_data"}