Move *args init from ApiMessage to DataContainer (#2737)

Author: dpkp

kafka/protocol/new/api_message.py

@@ -86,15 +86,8 @@ def __init_subclass__(cls, **kw):
 
     def __init__(self, *args, **kwargs):
         self._header = None
-        self._version = None
-        if 'version' in kwargs:
-            self.API_VERSION = kwargs['version']
-        if len(args) > 0:
-            untagged_fields = self._struct.untagged_fields(self.API_VERSION)
-            if len(args) != len(untagged_fields):
-                raise RuntimeError('Unable to init ApiMessage via positional args: unexpected len')
-            kwargs.update({field.name: args[i] for i, field in enumerate(untagged_fields)})
-            args = ()
+        if 'version' not in kwargs:
+            kwargs['version'] = self._class_version # pylint: disable=E1101
         super().__init__(*args, **kwargs)
 
     @classproperty

kafka/protocol/new/data_container.py

@@ -22,9 +22,19 @@ def __init_subclass__(cls, **kwargs):
                         field.set_data_class(type(field.type_str, (DataContainer,), {'_struct': field}))
                     setattr(cls, field.type_str, field.data_class)
 
-    def __init__(self, version=None, **field_vals):
+    def __init__(self, *args, version=None, **field_vals):
         assert self._struct is not None
         self._version = version
+        # Support positional arg init for convenience
+        if len(args) > 0:
+            if self._version is not None:
+                field_args = [field for field in self._struct._fields if field.for_version_q(self._version)]
+            else:
+                field_args = self._struct._fields
+            if len(args) > len(field_args):
+                raise RuntimeError('Unable to init DataContainer with %d positional args: unexpected %d' % (len(args), len(field_args)))
+            field_vals.update({field_args[i].name: arg for i, arg in enumerate(args)})
+            args = ()
         self.tags = None
         self.unknown_tags = None
         for field in self._struct._fields: