Fix key related errors printing messages within single quotes

CHANGELOG.rst

@@ -25,6 +25,7 @@ Fixed
 ^^^^^
 - Failures with subcommands and default_config_files when keys are repeated
   (`#160 <https://github.com/omni-us/jsonargparse/issues/160>`__).
+- Key related errors printing messages within single quotes.
 
 Changed
 ^^^^^^^

jsonargparse/_actions.py

@@ -11,7 +11,7 @@
 
 from ._common import get_class_instantiator, is_subclass, parser_context
 from ._loaders_dumpers import get_loader_exceptions, load_value
-from ._namespace import Namespace, split_key, split_key_root
+from ._namespace import Namespace, NSKeyError, split_key, split_key_root
 from ._optionals import FilesCompleterMethod, get_config_read_mode
 from ._type_checking import ArgumentParser
 from ._util import (
@@ -715,7 +715,9 @@ def get_subcommands(
                     candidate_subcommands_str = "{" + ",".join(available_subcommands) + "}"
                 else:
                     candidate_subcommands_str = "{" + ",".join(available_subcommands[:5]) + ", ...}"
-                raise KeyError(f'expected "{dest}" to be one of {candidate_subcommands_str}, but it was not provided.')
+                raise NSKeyError(
+                    f'expected "{dest}" to be one of {candidate_subcommands_str}, but it was not provided.'
+                )
 
         return subcommand_keys, [action._name_parser_map.get(s) for s in subcommand_keys]  # type: ignore
 

jsonargparse/_core.py

@@ -60,6 +60,7 @@
 )
 from ._namespace import (
     Namespace,
+    NSKeyError,
     is_meta_key,
     patch_namespace,
     recreate_branches,
@@ -881,7 +882,7 @@ def set_defaults(self, *args: Dict[str, Any], **kwargs: Any) -> None:
                 for dest, default in arg.items():
                     action = _find_action(self, dest)
                     if action is None:
-                        raise KeyError(f'No action for destination key "{dest}" to set its default.')
+                        raise NSKeyError(f'No action for key "{dest}" to set its default.')
                     elif isinstance(action, ActionConfigFile):
                         ActionConfigFile.set_default_error()
                     if isinstance(action, ActionTypeHint):
@@ -918,11 +919,11 @@ def get_default(self, dest: str) -> Any:
         """
         action, _ = _find_parent_action_and_subcommand(self, dest)
         if action is None or dest != action.dest:
-            raise KeyError(f'No action for destination key "{dest}" to get its default.')
+            raise NSKeyError(f'No action for key "{dest}" to get its default.')
 
         def check_suppressed_default():
             if action.default == argparse.SUPPRESS:
-                raise KeyError(f'Action for destination key "{dest}" does not specify a default.')
+                raise NSKeyError(f'Action for key "{dest}" does not specify a default.')
 
         if not self._get_default_config_files():
             check_suppressed_default()
@@ -1069,15 +1070,15 @@ def check_values(cfg):
                 elif key in self.groups and hasattr(self.groups[key], "instantiate_class"):
                     raise TypeError(f"Class group {key!r} got an unexpected value: {val}.")
                 else:
-                    raise KeyError(f'No action for destination key "{key}" to check its value.')
+                    raise NSKeyError(f'No action for key "{key}" to check its value.')
 
         try:
             if not skip_required and not lenient_check.get():
                 check_required(cfg, self)
             with parser_context(load_value_mode=self.parser_mode):
                 check_values(cfg)
         except (TypeError, KeyError) as ex:
-            prefix = "Configuration check failed :: "
+            prefix = "Validation failed: "
             message = ex.args[0]
             if prefix not in message:
                 message = prefix + message

jsonargparse/_namespace.py

@@ -26,6 +26,11 @@
 meta_keys = {"__default_config__", "__path__", "__orig__"}
 
 
+class NSKeyError(KeyError):
+    def __str__(self):
+        return str(self.args[0])
+
+
 def split_key(key: str) -> List[str]:
     return key.split(".")
 
@@ -146,10 +151,10 @@ def _parse_key(self, key: str) -> Tuple[str, Optional["Namespace"], str]:
             KeyError: When given invalid key.
         """
         if " " in key:
-            raise KeyError(f'Spaces not allowed in keys: "{key}".')
+            raise NSKeyError(f'Spaces not allowed in keys: "{key}".')
         key_split = split_key(key)
         if any(k == "" for k in key_split):
-            raise KeyError(f'Empty nested key: "{key}".')
+            raise NSKeyError(f'Empty nested key: "{key}".')
         key_split = [add_clash_mark(k) for k in key_split]
         leaf_key = key_split[-1]
         parent_ns: Namespace = self
@@ -169,7 +174,7 @@ def _parse_required_key(self, key: str) -> Tuple[str, "Namespace", str]:
         """Same as _parse_key but raises KeyError if key not found."""
         leaf_key, parent_ns, parent_key = self._parse_key(key)
         if parent_ns is None or not hasattr(parent_ns, leaf_key):
-            raise KeyError(f'Key "{key}" not found in namespace.')
+            raise NSKeyError(f'Key "{key}" not found in namespace.')
         return leaf_key, parent_ns, parent_key
 
     def _create_nested_namespace(self, key: str) -> "Namespace":
@@ -306,7 +311,7 @@ def update(
         """
         if not isinstance(value, Namespace):
             if not key:
-                raise KeyError("Key is required if value not a Namespace.")
+                raise NSKeyError("Key is required if value not a Namespace.")
             if not only_unset or key not in self:
                 self[key] = value
         else:

jsonargparse_tests/test_subclasses.py

@@ -539,7 +539,7 @@ def test_subclass_class_name_then_invalid_init_args(parser):
     parser.add_argument("--op", type=Union[Calendar, GzipFile])
     with pytest.raises(ArgumentError) as ctx:
         parser.parse_args(["--op=TextCalendar", "--op=GzipFile", "--op.firstweekday=2"])
-    ctx.match('No action for destination key "firstweekday"')
+    ctx.match('No action for key "firstweekday"')
 
 
 # dict parameter tests
@@ -1349,7 +1349,7 @@ def test_subclass_print_config(parser):
     assert obtained == {"a1": {"class_path": "calendar.Calendar", "init_args": {"firstweekday": 0}}, "a2": 7}
 
     err = get_parse_args_stderr(parser, ["--g.a1=calendar.Calendar", "--g.a1.invalid=1", "--print_config"])
-    assert 'No action for destination key "invalid"' in err
+    assert 'No action for key "invalid"' in err
 
 
 class PrintConfigRequired:
@@ -1427,7 +1427,7 @@ def test_subclass_error_unexpected_init_arg(parser):
     init_args = '"init_args": {"unexpected_arg": True}'
     with pytest.raises(ArgumentError) as ctx:
         parser.parse_args(["--op={" + class_path + ", " + init_args + "}"])
-    ctx.match('No action for destination key "unexpected_arg"')
+    ctx.match('No action for key "unexpected_arg"')
 
 
 def test_subclass_invalid_class_path_value(parser):

jsonargparse_tests/test_subcommands.py

@@ -55,15 +55,15 @@ def test_subcommands_undefined_subcommand(subcommands_parser):
 
 def test_subcommands_not_given_when_few_subcommands(subcommands_parser):
     err = get_parse_args_stderr(subcommands_parser, [])
-    assert "error: 'expected \"subcommand\" to be one of {a,b,B}, but it was not provided.'" in err
+    assert 'error: expected "subcommand" to be one of {a,b,B}, but it was not provided.' in err
 
 
 def test_subcommands_not_given_when_many_subcommands(parser, subparser):
     subcommands = parser.add_subcommands()
     for subcommand in range(ord("a"), ord("l") + 1):
         subcommands.add_subcommand(chr(subcommand), subparser)
     err = get_parse_args_stderr(parser, [])
-    assert "error: 'expected \"subcommand\" to be one of {a,b,c,d,e, ...}, but it was not provided.'" in err
+    assert 'error: expected "subcommand" to be one of {a,b,c,d,e, ...}, but it was not provided.' in err
 
 
 def test_subcommands_missing_required_subargument(subcommands_parser):
@@ -121,7 +121,7 @@ def test_subcommands_parse_string_implicit_subcommand(subcommands_parser):
     assert cfg["a"] == {"ap1": "ap1_cfg", "ao1": "ao1_def"}
     with pytest.raises(ArgumentError) as ctx:
         subcommands_parser.parse_string('{"a": {"ap1": "ap1_cfg", "unk": "unk_cfg"}}')
-    ctx.match('No action for destination key "unk"')
+    ctx.match('No action for key "unk"')
 
 
 def test_subcommands_parse_string_first_implicit_subcommand(subcommands_parser):