manage: Extract traverse method

manage.py

@@ -174,6 +174,20 @@ def coerce_to_list(data, key):
     return item
 
 
+def traverse(block):
+    def method(schema, pointer='', **kwargs):
+        if isinstance(schema, list):
+            for index, item in enumerate(schema):
+                method(item, pointer=f'{pointer}/{index}', **kwargs)
+        elif isinstance(schema, dict):
+            block(schema, pointer=pointer, **kwargs)
+
+            for key, value in schema.items():
+                method(value, pointer=f'{pointer}/{key}', **kwargs)
+
+    return method
+
+
 def get_metaschema():
     """
     Patches and returns the JSON Schema Draft 4 metaschema.
@@ -291,14 +305,11 @@ def update_refs_to_unversioned_definitions(schema):
             update_refs_to_unversioned_definitions(value)
 
 
-def get_unversioned_pointers(schema, fields, pointer=''):
+def get_unversioned_pointers(schema, fields):
     """
     Returns the JSON Pointers to ``id`` fields that must not be versioned if the object is in an array.
     """
-    if isinstance(schema, list):
-        for index, item in enumerate(schema):
-            get_unversioned_pointers(item, fields, pointer=f'{pointer}/{index}')
-    elif isinstance(schema, dict):
+    def block(schema, pointer='', fields=()):
         # Follows the logic of _get_merge_rules in merge.py from ocds-merge.
         types = coerce_to_list(schema, 'type')
 
@@ -318,50 +329,45 @@ def get_unversioned_pointers(schema, fields, pointer=''):
                     reference = pointer
                 fields.add(f'{reference}/properties/id')
 
-        for key, value in schema.items():
-            get_unversioned_pointers(value, fields, pointer=f'{pointer}/{key}')
+    traverse(block)(schema, fields=fields)
 
 
 def remove_omit_when_merged(schema):
     """
     Removes properties that set ``omitWhenMerged``.
     """
-    if isinstance(schema, list):
-        for item in schema:
-            remove_omit_when_merged(item)
-    elif isinstance(schema, dict):
+    def block(schema, **kwargs):
         for key, value in schema.items():
             if key == 'properties':
                 for prop in list(value):
                     if value[prop].get('omitWhenMerged'):
                         del value[prop]
                         if prop in schema['required']:
                             schema['required'].remove(prop)
-            remove_omit_when_merged(value)
+
+    traverse(block)(schema)
 
 
 def remove_metadata_and_extended_keywords(schema):
     """
     Removes metadata and extended keywords from properties and definitions.
     """
-    if isinstance(schema, list):
-        for item in schema:
-            remove_metadata_and_extended_keywords(item)
-    elif isinstance(schema, dict):
+    def block(schema, **kwargs):
         for key, value in schema.items():
             if key in ('definitions', 'properties'):
                 for subschema in value.values():
                     for keyword in keywords_to_remove:
                         subschema.pop(keyword, None)
-            remove_metadata_and_extended_keywords(value)
+
+    traverse(block)(schema)
 
 
 def get_dereferenced_release_schema(schema, output=None):
     """
     Returns the dereferenced release schema.
     """
-    # Without a deepcopy, changes to referenced objects are copied across referring objects. However, the deepcopy does
-    # not retain the `__reference__` property.
+    # Without a deepcopy, all referring objects will share the same referenced objects. However, the deepcopy does not
+    # retain the `__reference__` property. So, we need to pass both when recursing.
     if not output:
         output = deepcopy(schema)
 
@@ -473,10 +479,10 @@ def pre_commit():
     Update meta-schema.json, dereferenced-release-schema.json and versioned-release-validation-schema.json.
     """
     release_schema = json_load('release-schema.json')
-    jsonref_release_schema = json_load('release-schema.json', jsonref)
+    jsonref_schema = json_load('release-schema.json', jsonref)
 
     json_dump('meta-schema.json', get_metaschema())
-    json_dump('dereferenced-release-schema.json', get_dereferenced_release_schema(jsonref_release_schema))
+    json_dump('dereferenced-release-schema.json', get_dereferenced_release_schema(jsonref_schema))
     json_dump('versioned-release-validation-schema.json', get_versioned_release_schema(release_schema))