For consistency add_subclass_arguments now sets default None instead …

…of SUPPRESS (lightning#20103).

CHANGELOG.rst

@@ -12,6 +12,16 @@ The semantic versioning only considers the public API as described in
 paths are considered internals and can change in minor and patch releases.
 
 
+v4.33.0 (2024-09-??)
+--------------------
+
+Changed
+^^^^^^^
+- For consistency ``add_subclass_arguments`` now sets default ``None`` instead
+ of ``SUPPRESS`` (`lightning#20103
+ <https://github.com/Lightning-AI/pytorch-lightning/issue/20103>`__).
+
+
 v4.32.2 (2024-09-??)
 --------------------
 

jsonargparse/_signatures.py

@@ -3,7 +3,7 @@
 import dataclasses
 import inspect
 import re
-from argparse import SUPPRESS, ArgumentParser
+from argparse import ArgumentParser
 from contextlib import suppress
 from typing import Any, Callable, List, Optional, Set, Tuple, Type, Union
 
@@ -549,7 +549,7 @@ def add_subclass_arguments(
  }
  )
  if "default" not in kwargs:
- kwargs["default"] = SUPPRESS
+ kwargs["default"] = None
  self._add_signature_parameter(
  group, None, param, added_args, skip, sub_configs=True, instantiate=instantiate, **kwargs
  )

jsonargparse_tests/test_core.py

@@ -760,9 +760,7 @@ def test_default_config_files(parser, subtests, tmp_cwd):
  with subtests.test("get_default"):
  assert parser.get_default("op1") == "from default config file"
  parser.add_subclass_arguments(Calendar, "cal")
- with pytest.raises(KeyError) as ctx:
- parser.get_default("cal")
- ctx.match("does not specify a default")
+ assert parser.get_default("cal") is None
 
  with subtests.test("set invalid"):
  with pytest.raises(ValueError) as ctx:

jsonargparse_tests/test_subclasses.py

@@ -1338,9 +1338,9 @@ def test_add_subclass_required_group(parser):
 def test_add_subclass_not_required_group(parser):
  parser.add_subclass_arguments(Calendar, "cal", required=False)
  cfg = parser.parse_args([])
- assert cfg == Namespace()
+ assert cfg == Namespace(cal=None)
  init = parser.instantiate_classes(cfg)
- assert init == Namespace()
+ assert init == Namespace(cal=None)
 
 
 class ListUnionA:
@@ -1723,7 +1723,7 @@ def test_subclass_error_indentation_invalid_init_arg(parser):
  Given value: abc
  """
  ).strip()
- expected = textwrap.indent(expected, " ")
+ expected = textwrap.indent(expected, "  ")
  assert expected in err