_yaml: add 'get_mapping()' to MappingNode

This allows to get a mapping node from another 'MappingNode',
replacing 'node_get(my_mapping, key, type=dict)'

Also changes all places where 'node_get' was called like that by
the new API.

1 files changed, 2 insertions, 3 deletions

diff --git a/src/buildstream/_workspaces.py b/src/buildstream/_workspaces.py
index 9fbfb7e63..1adc52ac2 100644
--- a/src/buildstream/_workspaces.py
+++ b/src/buildstream/_workspaces.py
@@ -606,8 +606,7 @@ class Workspaces():
             }
 
         elif 1 <= version <= BST_WORKSPACE_FORMAT_VERSION:
-            workspaces = _yaml.node_get(workspaces, dict, "workspaces",
-                                        default_value=_yaml.new_empty_node())
+            workspaces = workspaces.get_mapping("workspaces", default={})
             res = {element: self._load_workspace(node)
                    for element, node in _yaml.node_items(workspaces)}
 
@@ -635,7 +634,7 @@ class Workspaces():
             'path': _yaml.node_get(node, str, 'path'),
             'last_successful': _yaml.node_get(node, str, 'last_successful', default_value=None),
             'running_files': _yaml.node_sanitize(
-                _yaml.node_get(node, dict, 'running_files', default_value=None),
+                node.get_mapping('running_files', default=None),
                 dict_type=dict),
         }
         return Workspace.from_dict(self._toplevel_project, dictionary)