Refactor: consistent use of _DEFAULT_MARKER_

omegaconf/_utils.py

@@ -63,6 +63,18 @@
 _CMP_TYPES = {t: i for i, t in enumerate([float, int, bool, str, type(None)])}
 
 
+class Marker:
+    def __init__(self, desc: str):
+        self.desc = desc
+
+    def __repr__(self) -> str:
+        return self.desc
+
+
+# To be used as default value when `None` is not an option.
+_DEFAULT_MARKER_: Any = Marker("_DEFAULT_MARKER_")
+
+
 class OmegaConfDumper(yaml.Dumper):  # type: ignore
     str_representer_added = False
 
@@ -76,14 +88,6 @@ def str_representer(dumper: yaml.Dumper, data: str) -> yaml.ScalarNode:
         )
 
 
-class Marker:
-    def __init__(self, desc: str):
-        self.desc = desc
-
-    def __repr__(self) -> str:
-        return self.desc
-
-
 def get_omega_conf_dumper() -> Type[OmegaConfDumper]:
     if not OmegaConfDumper.str_representer_added:
         OmegaConfDumper.add_representer(str, OmegaConfDumper.str_representer)

omegaconf/base.py

@@ -9,7 +9,7 @@
 from antlr4 import ParserRuleContext
 
 from ._utils import (
-    Marker,
+    _DEFAULT_MARKER_,
     ValueKind,
     _get_value,
     _is_missing_value,
@@ -33,8 +33,6 @@
 
 DictKeyType = Union[str, int, Enum, float, bool]
 
-_MARKER_: Any = Marker("_MARKER_")
-
 
 @dataclass
 class Metadata:
@@ -156,8 +154,8 @@ def _get_flag(self, flag: str) -> Optional[bool]:
         if cache is None:
             cache = self.__dict__["_flags_cache"] = {}
 
-        ret = cache.get(flag, _MARKER_)
-        if ret is _MARKER_:
+        ret = cache.get(flag, _DEFAULT_MARKER_)
+        if ret is _DEFAULT_MARKER_:
             ret = self._get_flag_no_cache(flag)
             cache[flag] = ret
         assert ret is None or isinstance(ret, bool)

omegaconf/basecontainer.py

@@ -9,7 +9,7 @@
 import yaml
 
 from ._utils import (
-    Marker,
+    _DEFAULT_MARKER_,
     _ensure_container,
     _get_value,
     _is_interpolation,
@@ -38,8 +38,6 @@
 if TYPE_CHECKING:
     from .dictconfig import DictConfig  # pragma: no cover
 
-DEFAULT_VALUE_MARKER: Any = Marker("DEFAULT_VALUE_MARKER")
-
 
 class BaseContainer(Container, ABC):
     # static
@@ -53,11 +51,11 @@ def _resolve_with_default(
         self,
         key: Union[DictKeyType, int],
         value: Node,
-        default_value: Any = DEFAULT_VALUE_MARKER,
+        default_value: Any = _DEFAULT_MARKER_,
     ) -> Any:
         """returns the value with the specified key, like obj.key and obj['key']"""
         if _is_missing_value(value):
-            if default_value is not DEFAULT_VALUE_MARKER:
+            if default_value is not _DEFAULT_MARKER_:
                 return default_value
             raise MissingMandatoryValue("Missing mandatory value: $FULL_KEY")
 

omegaconf/dictconfig.py

@@ -16,6 +16,7 @@
 )
 
 from ._utils import (
+    _DEFAULT_MARKER_,
     ValueKind,
     _get_value,
     _is_interpolation,
@@ -35,7 +36,7 @@
     valid_value_annotation_type,
 )
 from .base import Container, ContainerMetadata, DictKeyType, Node
-from .basecontainer import DEFAULT_VALUE_MARKER, BaseContainer
+from .basecontainer import BaseContainer
 from .errors import (
     ConfigAttributeError,
     ConfigKeyError,
@@ -345,7 +346,7 @@ def __getattr__(self, key: str) -> Any:
             raise AttributeError()
 
         try:
-            return self._get_impl(key=key, default_value=DEFAULT_VALUE_MARKER)
+            return self._get_impl(key=key, default_value=_DEFAULT_MARKER_)
         except ConfigKeyError as e:
             self._format_and_raise(
                 key=key, value=None, cause=e, type_override=ConfigAttributeError
@@ -361,7 +362,7 @@ def __getitem__(self, key: DictKeyType) -> Any:
         """
 
         try:
-            return self._get_impl(key=key, default_value=DEFAULT_VALUE_MARKER)
+            return self._get_impl(key=key, default_value=_DEFAULT_MARKER_)
         except AttributeError as e:
             self._format_and_raise(
                 key=key, value=None, cause=e, type_override=ConfigKeyError
@@ -414,7 +415,7 @@ def _get_impl(self, key: DictKeyType, default_value: Any) -> Any:
         try:
             node = self._get_node(key=key, throw_on_missing_key=True)
         except (ConfigAttributeError, ConfigKeyError):
-            if default_value is not DEFAULT_VALUE_MARKER:
+            if default_value is not _DEFAULT_MARKER_:
                 return default_value
             else:
                 raise
@@ -449,7 +450,7 @@ def _get_node(
             raise MissingMandatoryValue("Missing mandatory value")
         return value
 
-    def pop(self, key: DictKeyType, default: Any = DEFAULT_VALUE_MARKER) -> Any:
+    def pop(self, key: DictKeyType, default: Any = _DEFAULT_MARKER_) -> Any:
         try:
             if self._get_flag("readonly"):
                 raise ReadonlyConfigError("Cannot pop from read-only node")
@@ -470,7 +471,7 @@ def pop(self, key: DictKeyType, default: Any = DEFAULT_VALUE_MARKER) -> Any:
                 del self[key]
                 return value
             else:
-                if default is not DEFAULT_VALUE_MARKER:
+                if default is not _DEFAULT_MARKER_:
                     return default
                 else:
                     full = self._get_full_key(key=key)

omegaconf/omegaconf.py

@@ -28,7 +28,7 @@
 
 from . import DictConfig, DictKeyType, ListConfig
 from ._utils import (
-    Marker,
+    _DEFAULT_MARKER_,
     _ensure_container,
     _get_value,
     _is_none,
@@ -73,12 +73,6 @@
 
 MISSING: Any = "???"
 
-# Marker used:
-# -  in OmegaConf.create() to differentiate between creating an empty {} DictConfig
-#    and creating a DictConfig with None content
-# - in env() to detect between no default value vs a default value set to None
-_EMPTY_MARKER_: Any = Marker("_EMPTY_MARKER_")
-
 Resolver = Callable[..., Any]
 
 
@@ -115,9 +109,9 @@ def legacy_env(key: str, default: Optional[str] = None) -> Any:
             else:
                 raise ValidationError(f"Environment variable '{key}' not found")
 
-    def env(key: str, default: Optional[str] = _EMPTY_MARKER_) -> Optional[str]:
+    def env(key: str, default: Optional[str] = _DEFAULT_MARKER_) -> Optional[str]:
         if (
-            default is not _EMPTY_MARKER_
+            default is not _DEFAULT_MARKER_
             and default is not None
             and not isinstance(default, str)
         ):
@@ -129,7 +123,7 @@ def env(key: str, default: Optional[str] = _EMPTY_MARKER_) -> Optional[str]:
         try:
             return os.environ[key]
         except KeyError:
-            if default is not _EMPTY_MARKER_:
+            if default is not _DEFAULT_MARKER_:
                 return default
             else:
                 raise KeyError(f"Environment variable '{key}' not found")
@@ -219,7 +213,7 @@ def create(
 
     @staticmethod
     def create(  # noqa F811
-        obj: Any = _EMPTY_MARKER_,
+        obj: Any = _DEFAULT_MARKER_,
         parent: Optional[BaseContainer] = None,
         flags: Optional[Dict[str, bool]] = None,
     ) -> Union[DictConfig, ListConfig]:
@@ -684,7 +678,7 @@ def select(
         cfg: Container,
         key: str,
         *,
-        default: Any = _EMPTY_MARKER_,
+        default: Any = _DEFAULT_MARKER_,
         throw_on_resolution_failure: bool = True,
         throw_on_missing: bool = False,
     ) -> Any:
@@ -696,13 +690,13 @@ def select(
                     throw_on_resolution_failure=throw_on_resolution_failure,
                 )
             except ConfigKeyError:
-                if default is not _EMPTY_MARKER_:
+                if default is not _DEFAULT_MARKER_:
                     return default
                 else:
                     raise
 
             if (
-                default is not _EMPTY_MARKER_
+                default is not _DEFAULT_MARKER_
                 and _root is not None
                 and _last_key is not None
                 and _last_key not in _root
@@ -806,7 +800,7 @@ def to_yaml(cfg: Any, *, resolve: bool = False, sort_keys: bool = False) -> str:
 
     @staticmethod
     def _create_impl(  # noqa F811
-        obj: Any = _EMPTY_MARKER_,
+        obj: Any = _DEFAULT_MARKER_,
         parent: Optional[BaseContainer] = None,
         flags: Optional[Dict[str, bool]] = None,
     ) -> Union[DictConfig, ListConfig]:
@@ -815,7 +809,7 @@ def _create_impl(  # noqa F811
             from .dictconfig import DictConfig
             from .listconfig import ListConfig
 
-            if obj is _EMPTY_MARKER_:
+            if obj is _DEFAULT_MARKER_:
                 obj = {}
             if isinstance(obj, str):
                 obj = yaml.load(obj, Loader=get_yaml_loader())