Read-only list can no longer be replaced with command line override

news/39.bugfix

@@ -0,0 +1 @@
+Read-only list can no longer be replaced with command line override

omegaconf/config.py

@@ -166,7 +166,10 @@ def get_full_key(self, key):
                             break
             elif isinstance(parent, ListConfig):
                 if child is None:
-                    full_key = "[{}]".format(key)
+                    if key == "":
+                        full_key = key
+                    else:
+                        full_key = "[{}]".format(key)
                 else:
                     for idx, v in enumerate(parent):
                         if id(v) == id(child):
@@ -415,6 +418,9 @@ def merge_with(self, *others):
             if isinstance(self, DictConfig) and isinstance(other, DictConfig):
                 Config._map_merge(self, other)
             elif isinstance(self, ListConfig) and isinstance(other, ListConfig):
+                if self._get_flag("readonly"):
+                    raise ReadonlyConfigError(self.get_full_key(""))
+
                 self.__dict__["content"] = copy.deepcopy(other.content)
             else:
                 raise TypeError("Merging DictConfig with ListConfig is not supported")

tests/test_readonly.py

@@ -133,3 +133,11 @@ def test_readonly_list_sort():
     with pytest.raises(ReadonlyConfigError):
         c.sort()
     assert c == [3, 1, 2]
+
+
+def test_readonly_from_cli():
+    c = OmegaConf.create({"foo": {"bar": [1]}})
+    OmegaConf.set_readonly(c, True)
+    cli = OmegaConf.from_dotlist(["foo.bar=[2]"])
+    with pytest.raises(ReadonlyConfigError, match="foo.bar"):
+        OmegaConf.merge(c, cli)