Sort lists in exported dashboards

superset/superset/connectors/base/models.py

@@ -358,6 +358,7 @@ class BaseColumn(AuditMixinNullable, ImportMixin):
 
     # [optional] Set this to support import/export functionality
     export_fields = []
+    export_ordering = 'column_name'
 
     def __repr__(self):
         return self.column_name
@@ -419,6 +420,8 @@ class BaseMetric(AuditMixinNullable, ImportMixin):
     d3format = Column(String(128))
     warning_text = Column(Text)
 
+    export_ordering = 'metric_name'
+
     """
     The interface should also declare a datasource relationship pointing
     to a derivative of BaseDatasource, along with a FK

superset/superset/connectors/sqla/models.py

@@ -289,6 +289,7 @@ class SqlaTable(Model, BaseDatasource):
         f for f in export_fields if f not in ('table_name', 'database_id')]
     export_parent = 'database'
     export_children = ['metrics', 'columns']
+    export_ordering = 'table_name'
 
     sqla_aggregations = {
         'COUNT_DISTINCT': lambda column_name: sa.func.COUNT(sa.distinct(column_name)),

superset/superset/models/core.py

@@ -657,7 +657,8 @@ def export_dashboards(cls, dashboard_ids):
             )
             # remove ids and relations (like owners, created by, slices, ...)
             copied_dashboard = dashboard.copy()
-            for slc in dashboard.slices:
+            sorted_slices = sorted(dashboard.slices, key=lambda x: (x.slice_name or ''))
+            for slc in sorted_slices:
                 datasource_ids.add((slc.datasource_id, slc.datasource_type))
                 copied_slc = slc.copy()
                 # save original id into json
@@ -685,6 +686,11 @@ def export_dashboards(cls, dashboard_ids):
                 datasource_class = copied_datasource.__class__
                 for field_name in datasource_class.export_children:
                     field_val = getattr(eager_datasource, field_name).copy()
+                    sort_by = None
+                    if len(field_val) > 0:
+                        sort_by = field_val[0].export_ordering
+                    if sort_by:
+                        field_val = sorted(field_val, key=lambda x: getattr(x, sort_by))
                     # set children without creating ORM relations
                     copied_datasource.__dict__[field_name] = field_val
                 eager_datasources.append(copied_datasource)

superset/superset/models/helpers.py

@@ -56,6 +56,11 @@ class ImportMixin(object):
     # The names of the attributes
     # that are available for import and export
 
+    # If a collection is exported, this str represents by which argument
+    # to sort the collection achieve a deterministic order.
+    # Deterministic ordering is useful for diffing and unit tests
+    export_ordering = None
+
     @classmethod
     def _parent_foreign_key_mappings(cls):
         """Get a mapping of foreign name to the local name of foreign keys"""
@@ -203,16 +208,22 @@ def export_to_dict(self, recursive=True, include_parent_ref=False,
                     }
         if recursive:
             for c in self.export_children:
-                # sorting to make lists of children stable
-                dict_rep[c] = sorted(
-                    [
+                sort_by = None
+                orm_children = getattr(self, c)
+                children = []
+                if orm_children:
+                    children = [
                         child.export_to_dict(
                             recursive=recursive,
                             include_parent_ref=include_parent_ref,
                             include_defaults=include_defaults,
-                        ) for child in getattr(self, c)
-                    ],
-                    key=lambda k: sorted(k.items()))
+                        ) for child in orm_children
+                    ]
+                    sort_by = orm_children[0].export_ordering
+                # sorting to make lists of children stable
+                if sort_by:
+                    children = sorted(children, key=lambda x: x.get(sort_by))
+                dict_rep[c] = children
 
         return dict_rep