add __delattr__ to DictConfig (#703)

omegaconf/dictconfig.py

@@ -372,6 +372,26 @@ def __getitem__(self, key: DictKeyType) -> Any:
         except Exception as e:
             self._format_and_raise(key=key, value=None, cause=e)
 
+    def __delattr__(self, key: str) -> None:
+        """
+        Allow deleting dictionary values as attributes
+        :param key:
+        :return:
+        """
+        if self._get_flag("readonly"):
+            self._format_and_raise(
+                key=key,
+                value=None,
+                cause=ReadonlyConfigError(
+                    "DictConfig in read-only mode does not support deletion"
+                ),
+            )
+        try:
+            del self.__dict__["_content"][key]
+        except KeyError:
+            msg = "Attribute not found: '$KEY'"
+            self._format_and_raise(key=key, value=None, cause=ConfigAttributeError(msg))
+
     def __delitem__(self, key: DictKeyType) -> None:
         key = self._validate_and_normalize_key(key)
         if self._get_flag("readonly"):

tests/test_basic_ops_dict.py

@@ -75,6 +75,23 @@ def test_getattr_dict() -> None:
     assert {"b": 1} == c.a
 
 
+@mark.parametrize("struct", [False, True])
+@mark.parametrize(
+    "cfg",
+    [
+        param({"name": "alice", "age": 1}, id="dict"),
+        param(User(name="alice", age=1), id="structured_config"),
+    ],
+)
+def test_delattr(cfg: Any, struct: bool) -> None:
+    cfg = OmegaConf.create(cfg)
+    OmegaConf.set_struct(cfg, struct)
+    delattr(cfg, "name")
+    assert cfg == {"age": 1}
+    with raises(ConfigAttributeError):
+        delattr(cfg, "c")
+
+
 @mark.parametrize(
     "key,match",
     [

tests/test_errors.py

@@ -781,6 +781,17 @@ def finalize(self, cfg: Any) -> None:
         ),
         id="dict,structured:del",
     ),
+    param(
+        Expected(
+            create=lambda: create_readonly({"foo": "bar"}),
+            op=lambda cfg: cfg.__delattr__("foo"),
+            exception_type=ReadonlyConfigError,
+            msg="DictConfig in read-only mode does not support deletion",
+            key="foo",
+            child_node=lambda cfg: cfg.foo,
+        ),
+        id="dict,readonly:delattr",
+    ),
     # creating structured config
     param(
         Expected(

tests/test_readonly.py

@@ -51,6 +51,12 @@
             raises(ReadonlyConfigError, match="a"),
             id="dict_delitem",
         ),
+        param(
+            {"a": 10},
+            lambda c: c.__delattr__("a"),
+            raises(ReadonlyConfigError, match="a"),
+            id="dict_delattr",
+        ),
         # list
         param(
             [],