Deprecate add_dataclass_arguments and related changes

CHANGELOG.rst

@@ -12,9 +12,24 @@ The semantic versioning only considers the public API as described in
 paths are considered internals and can change in minor and patch releases.
 
 
-v4.34.1 (2024-12-02)
+v4.35.0 (2024-12-??)
 --------------------
 
+Changed
+^^^^^^^
+- Argument groups created from dataclass-like that have zero configurable
+  arguments no longer adds a config loader (`#634
+  <https://github.com/omni-us/jsonargparse/pull/634>`__).
+
+Deprecated
+^^^^^^^^^^
+- ``add_dataclass_arguments`` is deprecated and will be removed in v5.0.0.
+  Instead use ``add_class_arguments`` (`#634
+  <https://github.com/omni-us/jsonargparse/pull/634>`__).
+
+
+v4.34.1 (2024-12-02)
+
 Fixed
 ^^^^^
 - List of dataclass with nested dataclass attribute fails to parse (`#625

jsonargparse/_actions.py

@@ -9,7 +9,7 @@
 from contextvars import ContextVar
 from typing import Any, Dict, List, Optional, Tuple, Type, Union
 
-from ._common import Action, get_class_instantiator, is_subclass, parser_context
+from ._common import Action, is_subclass, parser_context
 from ._loaders_dumpers import get_loader_exceptions, load_value
 from ._namespace import Namespace, NSKeyError, split_key, split_key_root
 from ._optionals import get_config_read_mode
@@ -333,10 +333,6 @@ def _load_config(self, value, parser):
     def check_type(self, value, parser):
         return self._load_config(value, parser)
 
-    def instantiate_classes(self, value):
-        instantiator_fn = get_class_instantiator()
-        return instantiator_fn(self.basetype, **value)
-
 
 class _ActionHelpClassPath(Action):
     sub_add_kwargs: Dict[str, Any] = {}

jsonargparse/_core.py

@@ -124,7 +124,7 @@ def add_argument(self, *args, enable_path: bool = False, **kwargs):
         if "type" in kwargs:
             if is_dataclass_like(kwargs["type"]):
                 nested_key = args[0].lstrip("-")
-                self.add_dataclass_arguments(kwargs.pop("type"), nested_key, **kwargs)
+                self.add_class_arguments(kwargs.pop("type"), nested_key, **kwargs)
                 return _find_action(parser, nested_key)
             if ActionTypeHint.is_supported_typehint(kwargs["type"]):
                 args = ActionTypeHint.prepare_add_argument(
@@ -176,6 +176,33 @@ def add_argument_group(self, *args, name: Optional[str] = None, **kwargs) -> "_A
             parser.groups[name] = group  # type: ignore[union-attr]
         return group
 
+    def set_defaults(self, *args: Dict[str, Any], **kwargs: Any) -> None:
+        """Sets default values from dictionary or keyword arguments.
+
+        Args:
+            *args: Dictionary defining the default values to set.
+            **kwargs: Sets default values based on keyword arguments.
+
+        Raises:
+            KeyError: If key not defined in the parser.
+        """
+        for arg in args:
+            for dest, default in arg.items():
+                action = _find_action(self, dest)
+                if action is None:
+                    raise NSKeyError(f'No action for key "{dest}" to set its default.')
+                elif isinstance(action, ActionConfigFile):
+                    ActionConfigFile.set_default_error()
+                elif isinstance(action, _ActionConfigLoad):
+                    default = {f"{dest}.{k}": v for k, v in default.items()}
+                    self.set_defaults(default)
+                    continue
+                if isinstance(action, ActionTypeHint):
+                    default = action.normalize_default(default)
+                self._defaults[dest] = action.default = default
+        if kwargs:
+            self.set_defaults(kwargs)
+
 
 class _ArgumentGroup(ActionsContainer, argparse._ArgumentGroup):
     """Extension of argparse._ArgumentGroup to support additional functionalities."""
@@ -884,29 +911,6 @@ def save_paths(cfg):
 
     ## Methods related to defaults ##
 
-    def set_defaults(self, *args: Dict[str, Any], **kwargs: Any) -> None:
-        """Sets default values from dictionary or keyword arguments.
-
-        Args:
-            *args: Dictionary defining the default values to set.
-            **kwargs: Sets default values based on keyword arguments.
-
-        Raises:
-            KeyError: If key not defined in the parser.
-        """
-        for arg in args:
-            for dest, default in arg.items():
-                action = _find_action(self, dest)
-                if action is None:
-                    raise NSKeyError(f'No action for key "{dest}" to set its default.')
-                elif isinstance(action, ActionConfigFile):
-                    ActionConfigFile.set_default_error()
-                if isinstance(action, ActionTypeHint):
-                    default = action.normalize_default(default)
-                self._defaults[dest] = action.default = default
-        if kwargs:
-            self.set_defaults(kwargs)
-
     def _get_default_config_files(self) -> List[Tuple[Optional[str], Path]]:
         default_config_files = []
 
@@ -1179,7 +1183,7 @@ def instantiate_classes(
         cfg = strip_meta(cfg)
         for component in components:
             ActionLink.apply_instantiation_links(self, cfg, target=component.dest)
-            if isinstance(component, (ActionTypeHint, _ActionConfigLoad)):
+            if isinstance(component, ActionTypeHint):
                 try:
                     value, parent, key = cfg.get_value_and_parent(component.dest)
                 except (KeyError, AttributeError):

jsonargparse/_deprecated.py

@@ -520,6 +520,17 @@ def error_handler(self, error_handler):
         else:
             raise ValueError("error_handler can be either a Callable or None.")
 
+    @deprecated(
+        """
+        add_dataclass_arguments was deprecated in v4.35.0 and will be removed in
+        v5.0.0. Instead use add_class_arguments.
+    """
+    )
+    def add_dataclass_arguments(self, *args, **kwargs):
+        if "title" in kwargs:
+            kwargs["help"] = kwargs.pop("title")
+        return self.add_class_arguments(*args, **kwargs)
+
 
 ParserError = ArgumentError
 

jsonargparse/_signatures.py

@@ -4,7 +4,6 @@
 import inspect
 import re
 from argparse import SUPPRESS, ArgumentParser
-from contextlib import suppress
 from typing import Any, Callable, List, Optional, Set, Tuple, Type, Union
 
 from ._actions import _ActionConfigLoad
@@ -14,6 +13,7 @@
     get_generic_origin,
     get_unaliased_type,
     is_dataclass_like,
+    is_final_class,
     is_subclass,
 )
 from ._namespace import Namespace
@@ -53,7 +53,7 @@ def add_class_arguments(
         nested_key: Optional[str] = None,
         as_group: bool = True,
         as_positional: bool = False,
-        default: Optional[Union[dict, Namespace, LazyInitBaseClass]] = None,
+        default: Optional[Union[dict, Namespace, LazyInitBaseClass, Type]] = None,
         skip: Optional[Set[Union[str, int]]] = None,
         instantiate: bool = True,
         fail_untyped: bool = True,
@@ -82,16 +82,27 @@ def add_class_arguments(
             ValueError: When not given a class.
             ValueError: When there are required parameters without at least one valid type.
         """
-        if not inspect.isclass(get_generic_origin(get_unaliased_type(theclass))):
+        unaliased_class_type = get_unaliased_type(theclass)
+        if not inspect.isclass(get_generic_origin(unaliased_class_type)):
             raise ValueError(f"Expected 'theclass' parameter to be a class type, got: {theclass}")
         if not (
             isinstance(default, (NoneType, dict, Namespace))
-            or (isinstance(default, LazyInitBaseClass) and isinstance(default, theclass))
+            or (isinstance(default, LazyInitBaseClass) and isinstance(default, unaliased_class_type))
+            or (
+                not is_final_class(default.__class__)
+                and is_dataclass_like(default.__class__)
+                and isinstance(default, unaliased_class_type)
+            )
         ):
             raise ValueError(
-                f"Expected 'default' parameter to be a dict, Namespace or lazy instance of the class, got: {default}"
+                f"Expected 'default' to be dict, Namespace, lazy instance or dataclass-like, got: {default}"
             )
-        linked_targets = get_private_kwargs(kwargs, linked_targets=None)
+        linked_targets, help, _ = get_private_kwargs(
+            kwargs,
+            linked_targets=None,
+            help=None,
+            required=None,  # Ignored because provided when adding signatures, remove with dataclass inheritance support
+        )
 
         added_args = self._add_signature_arguments(
             theclass,
@@ -104,6 +115,7 @@ def add_class_arguments(
             sub_configs=sub_configs,
             instantiate=instantiate,
             linked_targets=linked_targets,
+            help=help,
         )
 
         if default:
@@ -112,6 +124,8 @@ def add_class_arguments(
             defaults = default
             if isinstance(default, LazyInitBaseClass):
                 defaults = default.lazy_get_init_args().as_dict()
+            elif is_dataclass_like(default.__class__):
+                defaults = dataclass_to_dict(default)
             elif isinstance(default, Namespace):
                 defaults = default.as_dict()
             if defaults:
@@ -230,6 +244,7 @@ def _add_signature_arguments(
         sub_configs: bool = False,
         instantiate: bool = True,
         linked_targets: Optional[Set[str]] = None,
+        help: Optional[str] = None,
     ) -> List[str]:
         """Adds arguments from parameters of objects based on signatures and docstrings.
 
@@ -273,7 +288,10 @@ def _add_signature_arguments(
                 )
 
         ## Create group if requested ##
-        doc_group = get_doc_short_description(function_or_class, method_name, logger=self.logger)
+        if help is not None:
+            doc_group = help
+        else:
+            doc_group = get_doc_short_description(function_or_class, method_name, logger=self.logger)
         component = getattr(function_or_class, method_name) if method_name else function_or_class
         container = self._create_group_if_requested(
             component,
@@ -424,67 +442,6 @@ def _add_signature_parameter(
                 f" type. Parameter '{name}' from '{src}' does not specify a type."
             )
 
-    def add_dataclass_arguments(
-        self,
-        theclass: Type,
-        nested_key: str,
-        default: Optional[Union[Type, dict]] = None,
-        as_group: bool = True,
-        fail_untyped: bool = True,
-        **kwargs,
-    ) -> List[str]:
-        """Adds arguments from a dataclass based on its field types and docstrings.
-
-        Args:
-            theclass: Class from which to add arguments.
-            nested_key: Key for nested namespace.
-            default: Value for defaults. Must be instance of or kwargs for theclass.
-            as_group: Whether arguments should be added to a new argument group.
-            fail_untyped: Whether to raise exception if a required parameter does not have a type.
-
-        Returns:
-            The list of arguments added.
-
-        Raises:
-            ValueError: When not given a dataclass.
-            ValueError: When default is not instance of or kwargs for theclass.
-        """
-        if not is_dataclass_like(theclass):
-            raise ValueError(f'Expected "theclass" argument to be a dataclass-like, given {theclass}')
-
-        doc_group = get_doc_short_description(theclass, logger=self.logger)
-        for key in ["help", "title"]:
-            if key in kwargs and kwargs[key] is not None:
-                doc_group = kwargs.pop(key)
-        group = self._create_group_if_requested(theclass, nested_key, as_group, doc_group, config_load_type=theclass)
-
-        defaults = {}
-        if default is not None:
-            if isinstance(default, dict):
-                with suppress(TypeError):
-                    default = theclass(**default)
-            if not isinstance(default, get_unaliased_type(theclass)):
-                raise ValueError(
-                    f'Expected "default" argument to be an instance of "{theclass.__name__}" '
-                    f"or its kwargs dict, given {default}"
-                )
-            defaults = dataclass_to_dict(default)
-
-        added_args: List[str] = []
-        param_kwargs = {k: v for k, v in kwargs.items() if k == "sub_configs"}
-        for param in get_signature_parameters(theclass, None, logger=self.logger):
-            self._add_signature_parameter(
-                group,
-                nested_key,
-                param,
-                added_args,
-                fail_untyped=fail_untyped,
-                default=defaults.get(param.name, inspect_empty),
-                **param_kwargs,
-            )
-
-        return added_args
-
     def add_subclass_arguments(
         self,
         baseclass: Union[Type, Tuple[Type, ...]],
@@ -618,8 +575,6 @@ def dataclass_to_dict(value) -> dict:
         pydantic_model = is_pydantic_model(type(value))
         if pydantic_model:
             return value.dict() if pydantic_model == 1 else value.model_dump()
-    if isinstance(value, LazyInitBaseClass):
-        return value.lazy_get_init_data().as_dict()
     return dataclasses.asdict(value)
 
 

jsonargparse/_typehints.py

@@ -1592,8 +1592,6 @@ def lazy_get_init_args(self) -> Namespace:
 
     def lazy_get_init_data(self):
         init_args = self.lazy_get_init_args()
-        if is_dataclass_like(self._lazy_class_type):
-            return init_args
         init = Namespace(class_path=get_import_path(self._lazy_class_type))
         if len(self._lazy_kwargs) > 0:
             init["init_args"] = init_args