Fix attribute name inflection

AUTHORS.rst

@@ -33,3 +33,4 @@ Contributors (chronological)
 - Areeb Jamal `@iamareebjamal <https://github.com/iamareebjamal>`_
 - Suren Khorenyan `@mahenzon <https://github.com/mahenzon>`_
 - Karthikeyan Singaravelan `@tirkarthi <https://github.com/tirkarthi>`_
+- Jannik Bamberger `@JBamberger <https://github.com/JBamberger>`_

marshmallow_jsonapi/schema.py

@@ -216,7 +216,7 @@ def unwrap_request(self, data, many, **kwargs):
 
     def on_bind_field(self, field_name, field_obj):
         """Schema hook override. When binding fields, set ``data_key`` to the inflected form of field_name."""
-        if not field_obj.data_key:
+        if not field_obj.data_key and not field_name == "id":
             field_obj.data_key = self.inflect(field_name)
         return None
 
@@ -321,7 +321,7 @@ def format_error(self, field_name, message, index=None):
             # JSONAPI identifier is a special field that exists above the attribute object.
             pointer.append("attributes")
 
-        pointer.append(self.inflect(field_name))
+        pointer.append(field_name)
 
         if relationship:
             pointer.append("data")
@@ -363,11 +363,11 @@ def format_item(self, item):
                 if value:
                     if "relationships" not in ret:
                         ret["relationships"] = self.dict_class()
-                    ret["relationships"][self.inflect(field_name)] = value
+                    ret["relationships"][field_name] = value
             else:
                 if "attributes" not in ret:
                     ret["attributes"] = self.dict_class()
-                ret["attributes"][self.inflect(field_name)] = value
+                ret["attributes"][field_name] = value
 
         links = self.get_resource_links(item)
         if links:

tests/test_options.py

@@ -6,6 +6,10 @@
 from tests.test_schema import make_serialized_author, get_error_by_field
 
 
+def add_postfix_inflection(text):
+    return text + "_x"
+
+
 def dasherize(text):
     return text.replace("_", "-")
 
@@ -33,6 +37,15 @@ class Meta:
         strict = True
 
 
+class PostfixInflectionSchema(Schema):
+    id = fields.Str()
+    test_attr = fields.Str(required=True, allow_none=False)
+
+    class Meta:
+        type_ = "postfix_inflection_type"
+        inflect = add_postfix_inflection
+
+
 class TestInflection:
     @pytest.fixture()
     def schema(self):
@@ -119,6 +132,31 @@ class Meta:
         ]
         assert related_href == f"http://test.test/posts/{post.id}/comments/"
 
+    def test_postfix_inflection(self):
+        schema = PostfixInflectionSchema()
+        data = schema.dump({"id": "5", "test_attr": None})
+        print(data)
+        assert "test_attr_x" in data["data"]["attributes"]
+
+    def test_postfix_inflection_errors(self):
+        schema = PostfixInflectionSchema()
+        errors = schema.validate(
+            {
+                "data": {
+                    "id": "5",
+                    "type": "postfix_inflection_type",
+                    "attributes": {"test_attr_x": None},
+                }
+            }
+        )
+
+        assert "errors" in errors
+        assert len(errors["errors"]) == 1
+
+        test_attr = get_error_by_field(errors, "test_attr_x")
+        assert test_attr
+        assert test_attr["source"]["pointer"] == "/data/attributes/test_attr_x"
+
 
 class AuthorAutoSelfLinkSchema(Schema):
     id = fields.Int(dump_only=True)