ListConfig append deepcopies input config nodes (#738)

news/601.bugfix

@@ -0,0 +1 @@
+ListConfig append now copies input config nodes

omegaconf/listconfig.py

@@ -252,6 +252,11 @@ def append(self, item: Any) -> None:
             index = len(self)
             self._validate_set(key=index, value=item)
 
+            if isinstance(item, Node):
+                do_deepcopy = not self._get_flag("no_deepcopy_set_nodes")
+                if do_deepcopy:
+                    item = copy.deepcopy(item)
+
             node = _maybe_wrap(
                 ref_type=self.__dict__["_metadata"].element_type,
                 key=index,

tests/test_basic_ops_dict.py

@@ -8,6 +8,7 @@
 
 from omegaconf import (
     MISSING,
+    AnyNode,
     DictConfig,
     DictKeyType,
     ListConfig,
@@ -1133,3 +1134,17 @@ def test_dictconfig_creation_with_parent_flag(flag: str, data: Any) -> None:
     parent._set_flag(flag, True)
     cfg = DictConfig(data, parent=parent)
     assert cfg == data
+
+
+@mark.parametrize(
+    "node",
+    [
+        param(AnyNode("hello"), id="any"),
+        param(DictConfig({}), id="dict"),
+        param(ListConfig([]), id="list"),
+    ],
+)
+def test_node_copy_on_set(node: Any) -> None:
+    cfg = OmegaConf.create({})
+    cfg.a = node
+    assert cfg.__dict__["_content"]["a"] is not node

tests/test_basic_ops_list.py

@@ -770,3 +770,17 @@ def test_listconfig_creation_with_parent_flag(flag: str) -> None:
     d = [1, 2, 3]
     cfg = ListConfig(d, parent=parent)
     assert cfg == d
+
+
+@mark.parametrize(
+    "node",
+    [
+        param(AnyNode("hello"), id="any"),
+        param(DictConfig({}), id="dict"),
+        param(ListConfig([]), id="list"),
+    ],
+)
+def test_node_copy_on_append(node: Any) -> None:
+    cfg = OmegaConf.create([])
+    cfg.append(node)
+    assert cfg.__dict__["_content"][0] is not node