prevent children of children in data associations

jdaviz/app.py

@@ -1283,10 +1283,12 @@ def add_data(self, data, data_label=None, notify_done=True, parent=None):
             The name associated with this data. If none is given, label is pulled
             from the input data (if `~glue.core.data.Data`) or a generic name is
             generated.
-        notify_done: bool
+        notify_done : bool
             Flag controlling whether a snackbar message is set when the data is
             added to the app. Set to False to avoid overwhelming the user if
             lots of data is getting loaded at once.
+        parent : str, optional
+            Associate the added Data entry as the child of layer ``parent``.
         """
 
         if not data_label and hasattr(data, "label"):
@@ -1300,6 +1302,13 @@ def add_data(self, data, data_label=None, notify_done=True, parent=None):
         # manage associated Data entries:
         self._add_assoc_data_as_parent(data_label)
         if parent is not None:
+            # Does the parent Data have a parent? If so, raise error:
+            parent_of_parent = self._get_assoc_data_parent(parent)
+            if parent_of_parent is not None:
+                raise NotImplementedError('Data associations are currently supported '
+                                          'between root layers (without parents) and their '
+                                          f'children, but the proposed parent "{parent}" has '
+                                          f'parent "{parent_of_parent}".')
             self._set_assoc_data_as_child(data_label, new_parent_label=parent)
 
         # Send out a toast message

jdaviz/configs/imviz/plugins/parsers.py

@@ -189,7 +189,6 @@ def _parse_image(app, file_obj, data_label, ext=None, parent=None):
 
         # TODO: generalize/centralize this for use in other configs too
         if parent is not None and ext == 'DQ':
-            print('data', data.main_components)
             # nans are used to mark "good" flags in the DQ colormap, so
             # convert DQ array to float to support nans:
             cid = data.get_component("DQ")

jdaviz/tests/test_app.py

@@ -184,3 +184,7 @@ def test_data_associations(imviz_helper):
 
     assert imviz_helper.app._get_assoc_data_children('parent_data') == ['child_data']
     assert imviz_helper.app._get_assoc_data_parent('child_data') == 'parent_data'
+
+    with pytest.raises(NotImplementedError):
+        # we don't (yet) allow children of children:
+        imviz_helper.load_data(data_child, data_label='grandchild_data', parent='child_data')