Merge pull request #2915 from martian0x80/layout-function-patch

Fixes 'AttributeError' when layout is a function that returns a list of components in dash layout setter

Author: T4rk1n

CHANGELOG.md

@@ -15,6 +15,7 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 - [#2896](https://github.com/plotly/dash/pull/2896) The tabIndex parameter of Div can accept number or string type. Fixes [#2891](https://github.com/plotly/dash/issues/2891)
 - [#2900](https://github.com/plotly/dash/pull/2900) Allow strings in layout list. Fixes [#2890](https://github.com/plotly/dash/issues/2890)
 - [#2908](https://github.com/plotly/dash/pull/2908) Fix when environment variables are ignored by Dash.run() at runtime. Fixes [#2902](https://github.com/plotly/dash/issues/2902)
+- [#2915](https://github.com/plotly/dash/pull/2915) Fix 'AttributeError' when layout is a function that returns a list of components. Fixes [#2905](https://github.com/plotly/dash/issues/2905)
 
 ## [2.17.1] - 2024-06-12
 

dash/dash.py

@@ -714,31 +714,9 @@ def layout(self, value):
             and not self.config.suppress_callback_exceptions
         ):
 
-            def simple_clone(c, children=None):
-                cls = type(c)
-                # in Py3 we can use the __init__ signature to reduce to just
-                # required args and id; in Py2 this doesn't work so we just
-                # empty out children.
-                sig = getattr(cls.__init__, "__signature__", None)
-                props = {
-                    p: getattr(c, p)
-                    for p in c._prop_names  # pylint: disable=protected-access
-                    if hasattr(c, p)
-                    and (
-                        p == "id" or not sig or sig.parameters[p].default == c.REQUIRED
-                    )
-                }
-                if props.get("children", children):
-                    props["children"] = children or []
-                return cls(**props)
-
             layout_value = self._layout_value()
             _validate.validate_layout(value, layout_value)
-            self.validation_layout = simple_clone(
-                # pylint: disable=protected-access
-                layout_value,
-                [simple_clone(c) for c in layout_value._traverse_ids()],
-            )
+            self.validation_layout = layout_value
 
     @property
     def index_string(self):