schema: use post_load to load parent info

invenio_communities/communities/schema.py

@@ -9,6 +9,7 @@
 
 """Community schema."""
 import re
+from copy import deepcopy
 from functools import partial
 from uuid import UUID
 
@@ -252,16 +253,11 @@ def post_dump(self, data, many, **kwargs):
 class CommunityParentSchema(BaseCommunitySchema):
     """Community parent schema."""
 
-    id = fields.String(required=True)
-    slug = SanitizedUnicode()
-    metadata = NestedAttribute(CommunityMetadataSchema)
-    access = NestedAttribute(CommunityAccessSchema)
-
 
 class CommunitySchema(BaseCommunitySchema):
     """Community schema."""
 
-    parent = NestedAttribute(CommunityParentSchema, allow_none=True)
+    parent = NestedAttribute(CommunityParentSchema, dump_only=True, allow_none=True)
 
     @post_dump
     def post_dump(self, data, many, **kwargs):
@@ -271,11 +267,15 @@ def post_dump(self, data, many, **kwargs):
             data.pop("parent", None)
         return data
 
-    @post_load
-    def filter_parent_id(self, in_data, **kwargs):
+    @post_load(pass_original=True)
+    def filter_parent_id(self, in_data, original_data, **kwargs):
         """Simply keep the parent id."""
-        if in_data.get("parent"):
-            in_data["parent"] = dict(id=in_data.get("parent", {}).get("id"))
+        if "parent" in original_data:
+            in_data["parent"] = (
+                dict(id=original_data["parent"]["id"])
+                if original_data["parent"]
+                else None
+            )
         return in_data
 
     @pre_load