Allow Dash children to be a tuple instead of a list

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.28.4 - 2018-10-18
+## Fixed
+- The `Component.traverse()` and `Component.traverse_with_paths()` methods now work correctly for components with `children` of type `tuple` (before, this only worked for `list`s). [#430](https://github.com/plotly/dash/pull/430)
+
 ## 0.28.3 - 2018-10-17
 ## Fixed
 - Fix http-equiv typo [#418](https://github.com/plotly/dash/pull/418)

dash/dash.py

@@ -775,9 +775,10 @@ def _validate_value(val, index=None):
                         )
 
                     # Children that are not of type Component or
-                    # collections.MutableSequence not returned by traverse
+                    # list/tuple not returned by traverse
                     child = getattr(j, 'children', None)
-                    if not isinstance(child, collections.MutableSequence):
+                    if not isinstance(child, (tuple,
+                                              collections.MutableSequence)):
                         if child and not _value_is_valid(child):
                             _raise_invalid(
                                 bad_val=child,
@@ -789,7 +790,7 @@ def _validate_value(val, index=None):
 
                 # Also check the child of val, as it will not be returned
                 child = getattr(val, 'children', None)
-                if not isinstance(child, collections.MutableSequence):
+                if not isinstance(child, (tuple, collections.MutableSequence)):
                     if child and not _value_is_valid(child):
                         _raise_invalid(
                             bad_val=child,

dash/development/base_component.py

@@ -16,7 +16,8 @@ def is_number(s):
 def _check_if_has_indexable_children(item):
     if (not hasattr(item, 'children') or
             (not isinstance(item.children, Component) and
-             not isinstance(item.children, collections.MutableSequence))):
+             not isinstance(item.children, (tuple,
+                                            collections.MutableSequence)))):
 
         raise KeyError
 
@@ -145,7 +146,7 @@ def _get_set_or_delete(self, id, operation, new_item=None):
                 pass
 
         # if children is like a list
-        if isinstance(self.children, collections.MutableSequence):
+        if isinstance(self.children, (tuple, collections.MutableSequence)):
             for i, item in enumerate(self.children):
                 # If the item itself is the one we're looking for
                 if getattr(item, 'id', None) == id:
@@ -221,7 +222,7 @@ def traverse_with_paths(self):
                 yield "\n".join(["[*] " + children_string, p]), t
 
         # children is a list of components
-        elif isinstance(children, collections.MutableSequence):
+        elif isinstance(children, (tuple, collections.MutableSequence)):
             for idx, i in enumerate(children):
                 list_path = "[{:d}] {:s} {}".format(
                     idx,
@@ -254,7 +255,7 @@ def __len__(self):
         elif isinstance(self.children, Component):
             length = 1
             length += len(self.children)
-        elif isinstance(self.children, collections.MutableSequence):
+        elif isinstance(self.children, (tuple, collections.MutableSequence)):
             for c in self.children:
                 length += 1
                 if isinstance(c, Component):

dash/version.py

@@ -1 +1 @@
-__version__ = '0.28.3'
+__version__ = '0.28.4'

tests/development/test_base_component.py

@@ -156,6 +156,16 @@ def test_traverse_with_nested_children_with_mixed_strings_and_without_lists(self
             c.children + [c3] + [c2] + c2.children
         )
 
+    def test_traverse_with_tuples(self):  # noqa: E501
+        c, c1, c2, c3, c4, c5 = nested_tree()
+        c2.children = tuple(c2.children)
+        c.children = tuple(c.children)
+        elements = [i for i in c.traverse()]
+        self.assertEqual(
+            elements,
+            list(c.children) + [c3] + [c2] + list(c2.children)
+        )
+
     def test_iter_with_nested_children_with_mixed_strings_and_without_lists(self):  # noqa: E501
         c = nested_tree()[0]
         keys = list(c.keys())