Fix regression of required not shown in help (#893)

Author: mauvilsa

CHANGELOG.rst

@@ -56,7 +56,8 @@ Changed
   <https://github.com/omni-us/jsonargparse/pull/887>`__).
 - Rely on ``required`` attributes to improve compatibility with third-party
   argparse extensions (`#890
-  <https://github.com/omni-us/jsonargparse/pull/890>`__).
+  <https://github.com/omni-us/jsonargparse/pull/890>`__, `#893
+  <https://github.com/omni-us/jsonargparse/pull/893>`__).
 
 
 v4.47.0 (2026-03-13)

jsonargparse/_core.py

@@ -78,6 +78,7 @@
 from ._paths import change_to_path_dir
 from ._required import (
     iter_required_keys,
+    restore_suppressed_required,
     set_required,
     suppress_required_actions,
 )
@@ -1369,7 +1370,7 @@ def format_help(self) -> str:
                 note = f"tried getting defaults considering default_config_files but failed due to: {ex}"
             group = self._default_config_files_group
             group.description = f"{self._default_config_files}, Note: {note}"
-        with parser_context(parent_parser=self, defaults_cache=defaults):
+        with restore_suppressed_required(), parser_context(parent_parser=self, defaults_cache=defaults):
             help_str = super().format_help()
         return help_str
 

jsonargparse/_required.py

@@ -1,9 +1,12 @@
 from argparse import Action, _SubParsersAction
 from contextlib import contextmanager
+from contextvars import ContextVar
 from typing import Iterator, Optional, Union
 
 from ._type_checking import ArgumentParser
 
+_suppressed_required_actions: ContextVar[tuple[Action, ...]] = ContextVar("_suppressed_required_actions", default=())
+
 
 def _iter_required_action_keys(parser: ArgumentParser) -> Iterator[str]:
     """Yields required destinations backed by real argparse actions."""
@@ -58,6 +61,7 @@ def _find_exact_action(parser: ArgumentParser, key: str) -> Optional[Action]:
 def suppress_required_actions(parser: ArgumentParser):
     """Temporarily disables required enforcement on real argparse actions."""
     suppressed = []
+    previously_suppressed = _suppressed_required_actions.get()
     visited = set()
 
     def visit(subparser):
@@ -73,8 +77,23 @@ def visit(subparser):
                     visit(choice_parser)
 
     visit(parser)
+    token = _suppressed_required_actions.set(previously_suppressed + tuple(suppressed))
     try:
         yield
     finally:
+        _suppressed_required_actions.reset(token)
         for action in reversed(suppressed):
             action.required = True
+
+
+@contextmanager
+def restore_suppressed_required():
+    """Temporarily restores required=True for actions suppressed by suppress_required_actions."""
+    suppressed = _suppressed_required_actions.get()
+    for action in suppressed:
+        action.required = True
+    try:
+        yield
+    finally:
+        for action in suppressed:
+            action.required = False

jsonargparse_tests/test_formatters.py

@@ -8,7 +8,7 @@
 import pytest
 
 from jsonargparse import ActionParser, ActionYesNo, ArgumentParser
-from jsonargparse_tests.conftest import get_parser_help, json_or_yaml_dump
+from jsonargparse_tests.conftest import get_parse_args_stdout, get_parser_help, json_or_yaml_dump
 
 
 @pytest.fixture
@@ -55,6 +55,12 @@ def test_help_required_and_default(parser):
     assert "Option v1. (required, default: v1)" in help_str
 
 
+def test_help_required_preserved_in_parse_args(parser):
+    parser.add_argument("--v1", type=int, help="Option v1.", required=True)
+    help_str = get_parse_args_stdout(parser, ["--help"])
+    assert "Option v1. (required, type: int)" in help_str
+
+
 def test_help_type_and_null_default(parser):
     parser.add_argument("--v2", type=int, help="Option v2.")
     help_str = get_parser_help(parser)

jsonargparse_tests/test_signatures.py

@@ -537,6 +537,41 @@ def test_add_method_parent_classes(parser):
     assert added_args == ["m.p2", "m.a1", "m.a2", "m.a3"]
 
 
+class Model:
+    pass
+
+
+class TrainerLike:
+    def foo(self, model: Model, x: int, y: float = 1.0):
+        """Sample extra function.
+
+        Args:
+            model: A model
+            x: The x
+            y: The y
+        """
+
+
+@skip_if_docstring_parser_unavailable
+def test_add_method_required_argument_in_parse_args_help(parser):
+    parser.add_method_arguments(TrainerLike, "foo", skip={"model"})
+
+    help_str = get_parse_args_stdout(parser, ["--help"])
+    assert "The x (required, type: int)" in help_str
+    assert "The y (type: float, default: 1.0)" in help_str
+
+
+@skip_if_docstring_parser_unavailable
+def test_add_method_required_argument_in_subcommand_parse_args_help(parser, subparser):
+    subparser.description = "Sample extra function:"
+    subparser.add_method_arguments(TrainerLike, "foo", skip={"model"})
+    parser.add_subcommands().add_subcommand("foo", subparser)
+
+    help_str = get_parse_args_stdout(parser, ["foo", "--help"])
+    assert "The x (required, type: int)" in help_str
+    assert "The y (type: float, default: 1.0)" in help_str
+
+
 # add_function_arguments tests
 
 

jsonargparse_tests/test_subclasses.py

@@ -1792,6 +1792,13 @@ def test_subclass_required_parameters_missing(parser):
     ctx.match("the following arguments are required: p1, p2")
 
 
+def test_subclass_help_required_parameters(parser):
+    parser.add_argument("--op", type=RequiredParamsMissing)
+    help_str = get_parse_args_stdout(parser, [f"--op.help={__name__}.RequiredParamsMissing"])
+    assert "(required, type: int)" in help_str
+    assert "(required, type: str)" in help_str
+
+
 def test_subclass_get_defaults_lazy_instance(parser):
     parser.add_argument("--op", type=RequiredParamsMissing, default=lazy_instance(RequiredParamsMissing, p1=1, p2="x"))
     defaults = parser.get_defaults()