Fix parser_mode not inherited by nested parsers

CHANGELOG.rst

@@ -23,6 +23,8 @@ Fixed
   <https://github.com/omni-us/jsonargparse/pull/560>`__).
 - ``--print_shtab`` not adding file completer for ``_ActionConfigLoad`` (`#562
   <https://github.com/omni-us/jsonargparse/pull/562>`__).
+- ``parser_mode`` not inherited by nested parsers (`#564
+  <https://github.com/omni-us/jsonargparse/pull/564>`__).
 
 
 v4.32.0 (2024-07-19)

jsonargparse/_typehints.py

@@ -615,7 +615,7 @@ def get_class_parser(val_class, sub_add_kwargs=None, skip_args=0):
         if skip_args:
             kwargs.setdefault("skip", set()).add(skip_args)
         parser = parent_parser.get()
-        parser = type(parser)(exit_on_error=False, logger=parser.logger)
+        parser = type(parser)(exit_on_error=False, logger=parser.logger, parser_mode=parser.parser_mode)
         remove_actions(parser, (ActionConfigFile, _ActionPrintConfig))
         if inspect.isclass(val_class):
             parser.add_class_arguments(val_class, **kwargs)

jsonargparse_tests/test_loaders_dumpers.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import os
+from dataclasses import dataclass
 from typing import List
 from unittest.mock import patch
 
@@ -129,6 +130,39 @@ def test_load_value_dash():
         assert " -  " == load_value(" -  ")
 
 
+@dataclass
+class CustomData:
+    fn: dict
+
+
+class CustomContainer:
+    def __init__(self, data: CustomData):
+        self.data = data
+
+
+def custom_loader(data):
+    data = yaml.safe_load(data)
+    if isinstance(data, dict) and "fn" in data:
+        data["fn"] = {k: custom_loader for k in data["fn"]}
+    return data
+
+
+def custom_dumper(data):
+    if "data" in data and "fn" in data["data"]:
+        data["data"]["fn"] = {k: "dumped" for k in data["data"]["fn"]}
+    return yaml_dump(data)
+
+
+def test_nested_parser_mode(parser):
+    set_loader("custom", custom_loader)
+    set_dumper("custom", custom_dumper)
+    parser.parser_mode = "custom"
+    parser.add_argument("--custom", type=CustomContainer)
+    cfg = parser.parse_args(['--custom.data={"fn": {"key": "value"}}'])
+    dump = yaml.safe_load(parser.dump(cfg))
+    assert dump["custom"]["init_args"]["data"] == {"fn": {"key": "dumped"}}
+
+
 @pytest.mark.skipif(
     not (omegaconf_support and "JSONARGPARSE_OMEGACONF_FULL_TEST" in os.environ),
     reason="only for omegaconf as the yaml loader",