For consistency add_subclass_arguments now sets default None instead of SUPPRESS

CHANGELOG.rst

@@ -34,6 +34,9 @@ Changed
 ^^^^^^^
 - Removed shtab experimental warning (`#561
   <https://github.com/omni-us/jsonargparse/pull/561>`__).
+- For consistency ``add_subclass_arguments`` now sets default ``None`` instead
+  of ``SUPPRESS`` (`lightning#20103
+  <https://github.com/Lightning-AI/pytorch-lightning/issue/20103>`__).
 
 
 v4.32.1 (2024-08-23)

jsonargparse/_formatters.py

@@ -25,7 +25,7 @@
 )
 from ._common import defaults_cache, parent_parser
 from ._link_arguments import ActionLink
-from ._namespace import Namespace
+from ._namespace import Namespace, NSKeyError
 from ._optionals import import_ruyaml
 from ._type_checking import ArgumentParser, ruyamlCommentedMap
 from ._typehints import ActionTypeHint, type_to_str
@@ -92,7 +92,7 @@ def _format_usage(self, *args, **kwargs) -> str:
             for key in parser.required_args:
                 try:
                     default = parser.get_default(key)
-                except KeyError:
+                except NSKeyError:
                     default = None
                 if default is None and f"[--{key} " in usage:
                     usage = re.sub(f"\\[(--{key} [^\\]]+)]", r"\1", usage, count=1)

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

@@ -26,6 +26,7 @@
     strip_meta,
 )
 from jsonargparse._formatters import get_env_var
+from jsonargparse._namespace import NSKeyError
 from jsonargparse._optionals import jsonnet_support, jsonschema_support, ruyaml_support
 from jsonargparse.typing import Path_fc, Path_fr, path_type
 from jsonargparse_tests.conftest import (
@@ -760,9 +761,7 @@ 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:
@@ -885,6 +884,37 @@ def test_set_get_defaults_multiple(parser, subparser, subtests):
         pytest.raises(KeyError, lambda: parser.get_default("v4"))
 
 
+def test_set_get_default_suppress_optional(parser):
+    parser.add_argument("--p1", type=int, default=SUPPRESS)
+    with pytest.raises(NSKeyError, match="does not specify a default"):
+        parser.get_default("p1")
+    assert parser.get_defaults() == Namespace()
+    help_str = get_parser_help(parser)
+    assert "--p1 P1     (type: int)" in help_str
+
+
+def test_set_get_default_suppress_required(parser):
+    parser.add_argument("--p2", type=int, default=SUPPRESS, required=True)
+    with pytest.raises(NSKeyError, match="does not specify a default"):
+        parser.get_default("p2")
+    assert parser.get_defaults() == Namespace()
+    help_str = get_parser_help(parser)
+    assert "--p2 P2     (required, type: int)" in help_str
+
+
+def test_set_get_default_suppress_default_config_file(parser, tmp_cwd):
+    default_config_file = tmp_cwd / "defaults.yaml"
+    default_config_file.write_text("p3: 1.2\n")
+
+    parser.default_config_files = [default_config_file]
+    parser.add_argument("--p3", type=float, default=SUPPRESS)
+    parser.add_argument("--p4", type=int, default=SUPPRESS)
+
+    assert parser.get_default("p3") == 1.2
+    with pytest.raises(NSKeyError, match="does not specify a default"):
+        parser.get_default("p4")
+
+
 def test_add_config_action_class(parser):
     parser.add_argument("--cfg", action=ActionConfigFile)
     parser.add_argument("--op", type=int)

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:
@@ -1723,8 +1723,8 @@ def test_subclass_error_indentation_invalid_init_arg(parser):
       Given value: abc
     """
     ).strip()
-    expected = textwrap.indent(expected, "    ")
-    assert expected in err
+    expected = textwrap.indent(expected, "        ")
+    assert "\n".join(expected.splitlines()) in "\n".join(err.splitlines())
 
 
 class ErrorIndentation2: