compose_dataclasses is deprecated and will be removed in v5.0.0 (#796)

Author: mauvilsa

CHANGELOG.rst

@@ -44,6 +44,9 @@ Deprecated
 - ``strip_meta`` is deprecated and will be removed in v5.0.0. Instead use
   ``.clone(with_meta=False)`` (`#795
   <https://github.com/omni-us/jsonargparse/pull/795>`__).
+- ``compose_dataclasses`` is deprecated and will be removed in v5.0.0. There is
+  no direct replacement, whoever is interested can copy the code (`#796
+  <https://github.com/omni-us/jsonargparse/pull/796>`__).
 
 
 v4.42.0 (2025-10-14)

jsonargparse/_deprecated.py

@@ -26,6 +26,7 @@
     "LoggerProperty",
     "ParserDeprecations",
     "ParserError",
+    "compose_dataclasses",
     "get_config_read_mode",
     "namespace_to_dict",
     "null_logger",
@@ -774,3 +775,25 @@ def set_yaml_argument_comment(self, text: str, cfg: ruamelCommentedMap, key: str
             depth: The nested level of the argument.
         """
         self._yaml_formatter.set_yaml_argument_comment(text, cfg, key, depth)
+
+
+@deprecated(
+    """
+    compose_dataclasses is deprecated and will be removed in v5.0.0. There is
+    no direct replacement, whoever is interested can copy the code from an old
+    release.
+"""
+)
+def compose_dataclasses(*args):
+    """Returns a dataclass inheriting all given dataclasses and properly handling __post_init__."""
+
+    import dataclasses
+
+    @dataclasses.dataclass
+    class ComposedDataclass(*args):
+        def __post_init__(self):
+            for arg in args:
+                if hasattr(arg, "__post_init__"):
+                    arg.__post_init__(self)
+
+    return ComposedDataclass

jsonargparse/_signatures.py

@@ -31,10 +31,7 @@
 from ._util import NoneType, get_import_path, get_private_kwargs, get_typehint_origin, iter_to_set_str
 from .typing import register_pydantic_type
 
-__all__ = [
-    "compose_dataclasses",
-    "SignatureArguments",
-]
+__all__ = ["SignatureArguments"]
 
 
 kinds = inspect._ParameterKind
@@ -614,16 +611,3 @@ def convert_to_dict(value) -> dict:
     if is_not_subclass_type(value_type):
         return init_args
     return {"class_path": get_import_path(value_type), "init_args": init_args}
-
-
-def compose_dataclasses(*args):
-    """Returns a dataclass inheriting all given dataclasses and properly handling __post_init__."""
-
-    @dataclasses.dataclass
-    class ComposedDataclass(*args):
-        def __post_init__(self):
-            for arg in args:
-                if hasattr(arg, "__post_init__"):
-                    arg.__post_init__(self)
-
-    return ComposedDataclass

jsonargparse_tests/test_dataclasses.py

@@ -12,7 +12,6 @@
     ArgumentError,
     ArgumentParser,
     Namespace,
-    compose_dataclasses,
     set_parsing_settings,
 )
 from jsonargparse._namespace import NSKeyError
@@ -336,25 +335,6 @@ def test_dataclass_fail_untyped_false(parser):
     assert isinstance(init.data.a3, str)
 
 
-@dataclasses.dataclass
-class ComposeA:
-    a: int = 1
-
-    def __post_init__(self):
-        self.a += 1
-
-
-@dataclasses.dataclass
-class ComposeB:
-    b: str = "1"
-
-
-def test_compose_dataclasses():
-    ComposeAB = compose_dataclasses(ComposeA, ComposeB)
-    assert 2 == len(dataclasses.fields(ComposeAB))
-    assert {"a": 3, "b": "2"} == dataclasses.asdict(ComposeAB(a=2, b="2"))  # pylint: disable=unexpected-keyword-arg
-
-
 @dataclasses.dataclass
 class NestedData:
     name: str = "name"

jsonargparse_tests/test_deprecated.py

@@ -18,6 +18,7 @@
     ArgumentError,
     ArgumentParser,
     Namespace,
+    compose_dataclasses,
     get_config_read_mode,
     set_config_read_mode,
     set_docstring_parse_options,
@@ -681,7 +682,6 @@ def test_import_from_deprecated():
         ("link_arguments", "ArgumentLinking"),
         ("loaders_dumpers", "set_loader"),
         ("namespace", "Namespace"),
-        ("signatures", "compose_dataclasses"),
         ("typehints", "lazy_instance"),
         ("util", "Path"),
         ("parameter_resolvers", "ParamData"),
@@ -802,3 +802,28 @@ def test_DefaultHelpFormatter_yaml_comments(parser):
         formatter.set_yaml_argument_comment("arg", cfg, "arg", 0)
     assert "set_yaml_argument_comment method is deprecated and will be removed in v5.0.0" in str(w[-1].message)
     assert "formatter.set_yaml_argument_comment(" in source[w[-1].lineno - 1]
+
+
+@dataclasses.dataclass
+class ComposeA:
+    a: int = 1
+
+    def __post_init__(self):
+        self.a += 1
+
+
+@dataclasses.dataclass
+class ComposeB:
+    b: str = "1"
+
+
+def test_compose_dataclasses():
+    with catch_warnings(record=True) as w:
+        ComposeAB = compose_dataclasses(ComposeA, ComposeB)
+    assert_deprecation_warn(
+        w,
+        message="compose_dataclasses is deprecated",
+        code="ComposeAB = compose_dataclasses(ComposeA, ComposeB)",
+    )
+    assert 2 == len(dataclasses.fields(ComposeAB))
+    assert {"a": 3, "b": "2"} == dataclasses.asdict(ComposeAB(a=2, b="2"))  # pylint: disable=unexpected-keyword-arg