Fix ModelSchema ignoring declared fields when using exclude

ninja/orm/factory.py

@@ -60,6 +60,14 @@ def create_schema(
             if optional_fields == "__all__":
                 optional_fields = [f.name for f in model_fields_list]
 
+        declared_fields = self._get_declared_fields(base_class)
+
+        model_fields_list = [
+            f
+            for f in self._selected_model_fields(model, fields, exclude)
+            if f.name not in declared_fields
+        ]
+
         definitions = {}
         for fld in model_fields_list:
             python_type, field_info = get_schema_field(
@@ -163,6 +171,17 @@ def _model_fields(self, model: Type[Model]) -> Iterator[DjangoField]:
                 continue
             yield cast(DjangoField, fld)
 
+    def _get_declared_fields(self, base_class: Type[Schema]) -> Set[str]:
+        # Extracts field names already declared in the base Schema class to prevent duplicates when generating model fields.
+        if not hasattr(self, "_annotation_cache"):
+            self._annotation_cache: Dict[Type[Schema], Set[str]] = {}
+
+        if base_class not in self._annotation_cache:
+            self._annotation_cache[base_class] = set(
+                getattr(base_class, "__annotations__", {}).keys()
+            )
+        return self._annotation_cache[base_class]
+
 
 factory = SchemaFactory()
 

tests/test_orm_metaclass.py

@@ -3,6 +3,7 @@
 
 from ninja import ModelSchema
 from ninja.errors import ConfigError
+from ninja.schema import Field
 
 
 def test_simple():
@@ -197,3 +198,40 @@ class OldConfigSchema(ModelSchema):
             class Config:
                 model = "User"
                 model_fields = ["x"]
+
+
+def test_field_alias_with_display_method():
+    class StatusModel(models.Model):
+        STATUS_CHOICES = [
+            ("NA", "Not assessed"),
+            ("IP", "In progress"),
+            ("CO", "Complete"),
+        ]
+        status = models.CharField(max_length=2, choices=STATUS_CHOICES, default="NA")
+
+        class Meta:
+            app_label = "tests"
+
+    class StatusSchemaFields(ModelSchema):
+        status: str = Field(alias="get_status_display")
+
+        class Meta:
+            model = StatusModel
+            fields = ["id", "status"]
+
+    class StatusSchemaExclude(ModelSchema):
+        status: str = Field(alias="get_status_display")
+
+        class Meta:
+            model = StatusModel
+            exclude = ["id"]
+
+    instance = StatusModel(id=4, status="NA")
+
+    schema_fields = StatusSchemaFields.from_orm(instance)
+    assert schema_fields.status == "Not assessed"
+    assert schema_fields.id == 4
+
+    schema_exclude = StatusSchemaExclude.from_orm(instance)
+    assert schema_exclude.status == "Not assessed"
+    assert not hasattr(schema_exclude, "id")