Avoid duplicated recursive calls in inventory CLI (#48598)

lib/ansible/cli/inventory.py

@@ -324,6 +324,8 @@ class InventoryCLI(CLI):
 
     def json_inventory(self, top):
 
+        seen = set()
+
         def format_group(group):
             results = {}
             results[group.name] = {}
@@ -332,7 +334,9 @@ class InventoryCLI(CLI):
             results[group.name]['children'] = []
             for subgroup in sorted(group.child_groups, key=attrgetter('name')):
                 results[group.name]['children'].append(subgroup.name)
+                if subgroup.name not in seen:
                     results.update(format_group(subgroup))
+                    seen.add(subgroup.name)
             if self.options.export:
                 results[group.name]['vars'] = self._get_group_variables(group)