Fix intermittent failure on add_parent test

arkindex/documents/models.py

@@ -294,11 +294,13 @@ class Element(IndexableModel):
             # and always tries to add a GROUP BY documents_elementpath.id, which returns
             # wildly incorrect results.
             # We use two CTEs here to make this already fast query twice as fast.
+            # The parent_paths CTE is sorted to avoid intermittent test failures.
             cursor.execute(
                 """
                 WITH parent_paths AS (
                     SELECT path FROM documents_elementpath
                     WHERE element_id = %(parent_id)s
+                    ORDER BY path
                 ), child_paths AS (
                     SELECT path FROM documents_elementpath
                     WHERE element_id = %(self_id)s

arkindex/documents/tests/test_edit_elementpath.py

@@ -98,7 +98,12 @@ class TestEditElementPath(FixtureTestCase):
                 'savepoint': f"s{_thread.get_ident()}_x{connections['default'].savepoint_state + 1}",
                 'A': elements['A'].id,
                 'B': elements['B'].id,
-                'X': elements['X'].id,
+                # Element A has two parents so it has two paths.
+                # add_parent will pick the first one to perform updates on the new child's paths,
+                # so it will be seen in the SQL queries. To avoid intermittent failures,
+                # add_parent sorts parent paths by `path`, so we apply the same sort here.
+                # The paths only contain one ID, X's or Y's.
+                'first_parent': elements['A'].paths.order_by('path').first().path[0],
             }
         ):
             elements['B'].add_parent(elements['A'])

arkindex/sql_validation/add_first_parent.sql

@@ -3,7 +3,8 @@ SAVEPOINT "{savepoint}";
 WITH parent_paths AS
     (SELECT path
      FROM documents_elementpath
-     WHERE element_id = '{A}'::uuid ),
+     WHERE element_id = '{A}'::uuid
+     ORDER BY path),
      child_paths AS
     (SELECT path
      FROM documents_elementpath
@@ -38,16 +39,16 @@ SELECT uuid_generate_v4(),
                1
 FROM documents_elementpath
 WHERE element_id = '{A}'::uuid
-    AND path <> ARRAY['{X}'::uuid];
+    AND path <> ARRAY['{first_parent}'::uuid];
 
 UPDATE "documents_elementpath"
-SET "path" = ARRAY['{X}'::uuid,
+SET "path" = ARRAY['{first_parent}'::uuid,
                    '{A}'::uuid]::uuid[], "ordering" = 1
 WHERE ("documents_elementpath"."element_id" = '{B}'::uuid
        AND "documents_elementpath"."path" = (ARRAY[])::uuid[]);
 
 UPDATE "documents_elementpath"
-SET "path" = array_cat(ARRAY['{X}'::uuid, '{A}'::uuid], "documents_elementpath"."path")::uuid[]
+SET "path" = array_cat(ARRAY['{first_parent}'::uuid, '{A}'::uuid], "documents_elementpath"."path")::uuid[]
 WHERE "documents_elementpath"."path" && (ARRAY['{B}'::uuid])::uuid[];
 
 INSERT INTO documents_elementpath (id, element_id, path, ordering)
@@ -57,10 +58,10 @@ SELECT uuid_generate_v4(),
        child_paths.ordering
 FROM documents_elementpath child_paths,
      documents_elementpath new_parent_paths
-WHERE child_paths.path @ > ARRAY['{X}'::uuid,
+WHERE child_paths.path @ > ARRAY['{first_parent}'::uuid,
                                  '{A}'::uuid,
                                  '{B}'::uuid]
     AND new_parent_paths.element_id = '{A}'::uuid
-    AND new_parent_paths.path <> ARRAY['{X}'::uuid];
+    AND new_parent_paths.path <> ARRAY['{first_parent}'::uuid];
 
 RELEASE SAVEPOINT "{savepoint}"

arkindex/sql_validation/add_second_parent.sql

@@ -3,7 +3,8 @@ SAVEPOINT "{savepoint}";
 WITH parent_paths AS
     (SELECT path
      FROM documents_elementpath
-     WHERE element_id = '{A}'::uuid ),
+     WHERE element_id = '{A}'::uuid
+     ORDER BY path),
      child_paths AS
     (SELECT path
      FROM documents_elementpath

arkindex/sql_validation/element_move_with_children.sql

@@ -38,7 +38,8 @@ SAVEPOINT "{savepoints[1]}";
 WITH parent_paths AS
     (SELECT path
      FROM documents_elementpath
-     WHERE element_id = '{destination_id}'::uuid ),
+     WHERE element_id = '{destination_id}'::uuid
+     ORDER BY path),
      child_paths AS
     (SELECT path
      FROM documents_elementpath

arkindex/sql_validation/element_move_without_child.sql

@@ -38,7 +38,8 @@ SAVEPOINT "{savepoints[1]}";
 WITH parent_paths AS
     (SELECT path
      FROM documents_elementpath
-     WHERE element_id = '{destination_id}'::uuid ),
+     WHERE element_id = '{destination_id}'::uuid
+     ORDER BY path),
      child_paths AS
     (SELECT path
      FROM documents_elementpath