Fix subsubcommand parse failing when default_env=True

CHANGELOG.rst

@@ -20,6 +20,8 @@ Fixed
 - Failure when getting parameters from a class created with
   ``class_from_function`` from a ``classmethod`` without parameter types (`#454
   <https://github.com/omni-us/jsonargparse/issues/454>`__).
+- Subsubcommand parse failing when ``default_env=True`` (`#465
+  <https://github.com/omni-us/jsonargparse/issues/465>`__).
 
 
 v4.27.5 (2024-02-12)

jsonargparse/_core.py

@@ -508,14 +508,17 @@ def parse_env(
         try:
             cfg = self._parse_defaults_and_environ(defaults, env=True, environ=env)
 
-            parsed_cfg = self._parse_common(
-                cfg=cfg,
-                env=True,
-                defaults=defaults,
-                with_meta=with_meta,
-                skip_check=skip_check,
-                skip_subcommands=skip_subcommands,
-            )
+            kwargs = {
+                "env": True,
+                "defaults": defaults,
+                "with_meta": with_meta,
+                "skip_check": skip_check,
+                "skip_subcommands": skip_subcommands,
+            }
+            if skip_check:
+                kwargs["fail_no_subcommand"] = False
+
+            parsed_cfg = self._parse_common(cfg=cfg, **kwargs)
 
         except (TypeError, KeyError) as ex:
             self.error(str(ex), ex)

jsonargparse_tests/test_subcommands.py

@@ -327,3 +327,20 @@ def test_subcommands_custom_instantiator(parser, subparser, subtests):
         init = parser.instantiate_classes(cfg)
         assert isinstance(init.cmd.cls, CustomInstantiationBase)
         assert init.cmd.cls.call == "subparser"
+
+
+def test_subsubcommand_default_env_true(parser, subparser):
+    parser.default_env = True
+    parser.env_prefix = "APP"
+    subsubparser = ArgumentParser()
+    subsubparser.add_argument("--v", type=int, default=1)
+    subcommands1 = parser.add_subcommands()
+    subcommands1.add_subcommand("s1", subparser)
+    subcommands2 = subparser.add_subcommands()
+    subcommands2.add_subcommand("s2", subsubparser)
+    cfg = parser.parse_args(["s1", "s2"])
+    assert cfg == Namespace(subcommand="s1", s1=Namespace(subcommand="s2", s2=Namespace(v=1)))
+
+    with patch.dict(os.environ, {"APP_SUBCOMMAND": "s1", "APP_S1__SUBCOMMAND": "s2"}):
+        cfg = parser.parse_args([])
+    assert cfg == Namespace(subcommand="s1", s1=Namespace(subcommand="s2", s2=Namespace(v=1)))