Add validation of None for non-optional AnyNode

omegaconf/base.py

@@ -403,7 +403,7 @@ def _resolve_interpolation_from_parse_tree(
     ) -> Optional["Node"]:
         from .basecontainer import BaseContainer
         from .nodes import AnyNode, ValueNode
-        from .omegaconf import _node_wrap
+        from .omegaconf import OmegaConf, _node_wrap
 
         try:
             resolved = self.resolve_parse_tree(
@@ -420,8 +420,22 @@ def _resolve_interpolation_from_parse_tree(
         # custom resolver), then we will need to wrap it within a Node.
         must_wrap = not isinstance(resolved, Node)
 
-        # If the node is typed, validate (and possibly convert) the result.
-        if isinstance(value, ValueNode) and not isinstance(value, AnyNode):
+        if isinstance(value, AnyNode):
+            # If the node is untyped, we still need to validate against `None`
+            # in case the `optional` flag is set to `False`.
+            if not value._is_optional() and OmegaConf.is_none(resolved):
+                if throw_on_resolution_failure:
+                    self._format_and_raise(
+                        key=key,
+                        value=resolved,
+                        cause=InterpolationValidationError(
+                            "Non optional field cannot be assigned None"
+                        ),
+                    )
+                return None
+
+        elif isinstance(value, ValueNode):
+            # If the node is typed, validate (and possibly convert) the result.
             res_value = _get_value(resolved)
             try:
                 conv_value = value.validate_and_convert(res_value)

tests/test_interpolation.py

@@ -920,6 +920,53 @@ def cast(t: Any, v: Any) -> Any:
     assert OmegaConf.select(cfg, key, throw_on_resolution_failure=False) is None
 
 
+@pytest.mark.parametrize(
+    ("cfg", "key", "expected_error"),
+    [
+        (
+            {"x": "${none}", "none": None},
+            "x",
+            pytest.raises(
+                InterpolationValidationError,
+                match=re.escape(
+                    dedent(
+                        """\
+                        Non optional field cannot be assigned None
+                            full_key: x
+                        """
+                    )
+                ),
+            ),
+        ),
+        (
+            {"x": "${get_none:}"},
+            "x",
+            pytest.raises(
+                InterpolationValidationError,
+                match=re.escape(
+                    dedent(
+                        """\
+                        Non optional field cannot be assigned None
+                            full_key: x
+                        """
+                    )
+                ),
+            ),
+        ),
+    ],
+)
+def test_interpolation_non_optional_any(
+    restore_resolvers: Any, cfg: Any, key: str, expected_error: Any
+) -> None:
+    OmegaConf.register_new_resolver("get_none", lambda: None)
+    cfg = OmegaConf.create(cfg)
+    node = cfg._get_node(key)
+    node._metadata.optional = False
+    with expected_error:
+        cfg[key]
+    assert OmegaConf.select(cfg, key, throw_on_resolution_failure=False) is None
+
+
 def test_type_validation_error_no_throw() -> None:
     cfg = OmegaConf.structured(User(name="Bond", age=SI("${name}")))
     bad_node = cfg._get_node("age")