[python] Fixes a breakage while deserializing the read-only attributes (#10155)

* fixes a breakage while deserializing the read-only attributes

* updating generated samples

* taking care of the PR comments

* updating samples

* protect against cases where _spec_property_naming may not be present

* updating samples

* adding tests for this issue

* other generated files

* taking care of the comments

* updating the generated samples

Co-authored-by: Aanisha Mishra <[email protected]>

Author: vvb

.generator/templates/model_utils.mustache

@@ -1450,7 +1450,10 @@ def get_allof_instances(self, model_args, constant_args):
     for allof_class in self._composed_schemas['allOf']:
 
         try:
-            allof_instance = allof_class(**model_args, **constant_args)
+            if constant_args.get('_spec_property_naming'):
+                allof_instance = allof_class._from_openapi_data(**model_args, **constant_args)
+            else:
+                allof_instance = allof_class(**model_args, **constant_args)
             composed_instances.append(allof_instance)
         except Exception as ex:
             raise ApiValueError(
@@ -1512,10 +1515,16 @@ def get_oneof_instance(cls, model_kwargs, constant_kwargs, model_arg=None):
 
         try:
             if not single_value_input:
-                oneof_instance = oneof_class(**model_kwargs, **constant_kwargs)
+                if constant_kwargs.get('_spec_property_naming'):
+                    oneof_instance = oneof_class._from_openapi_data(**model_kwargs, **constant_kwargs)
+                else:
+                    oneof_instance = oneof_class(**model_kwargs, **constant_kwargs)
             else:
                 if issubclass(oneof_class, ModelSimple):
-                    oneof_instance = oneof_class(model_arg, **constant_kwargs)
+                    if constant_kwargs.get('_spec_property_naming'):
+                        oneof_instance = oneof_class._from_openapi_data(model_arg, **constant_kwargs)
+                    else:
+                        oneof_instance = oneof_class(model_arg, **constant_kwargs)
                 elif oneof_class in PRIMITIVE_TYPES:
                     oneof_instance = validate_and_convert_types(
                         model_arg,
@@ -1570,7 +1579,10 @@ def get_anyof_instances(self, model_args, constant_args):
             continue
 
         try:
-            anyof_instance = anyof_class(**model_args, **constant_args)
+            if constant_args.get('_spec_property_naming'):
+                anyof_instance = anyof_class._from_openapi_data(**model_args, **constant_args)
+            else:
+                anyof_instance = anyof_class(**model_args, **constant_args)
             anyof_instances.append(anyof_instance)
         except Exception:
             pass