_yaml: Create 'from_dict' on Node and remove node creation methodsbschubert/rework-node-creations

Using 'Node.from_dict({})' can replace new_empty_node, and the rest
is not needed anymore.

- Adapt all call sites

7 files changed, 16 insertions, 32 deletions

diff --git a/src/buildstream/_context.py b/src/buildstream/_context.py
index 524305177..9b0db39d7 100644
--- a/src/buildstream/_context.py
+++ b/src/buildstream/_context.py
@@ -159,7 +159,7 @@ class Context():
         self._artifactcache = None
         self._sourcecache = None
         self._projects = []
-        self._project_overrides = _yaml.new_empty_node()
+        self._project_overrides = _yaml.Node.from_dict({})
         self._workspaces = None
         self._workspace_project_cache = WorkspaceProjectCache()
         self._log_handle = None
diff --git a/src/buildstream/_loader/loader.py b/src/buildstream/_loader/loader.py
index 73da5434a..da1e466c9 100644
--- a/src/buildstream/_loader/loader.py
+++ b/src/buildstream/_loader/loader.py
@@ -120,7 +120,7 @@ class Loader():
 
         # Set up a dummy element that depends on all top-level targets
         # to resolve potential circular dependencies between them
-        dummy_target = LoadElement(_yaml.new_empty_node(), "", self)
+        dummy_target = LoadElement(_yaml.Node.from_dict({}), "", self)
         dummy_target.dependencies.extend(
             LoadElement.Dependency(element, Symbol.RUNTIME)
             for element in target_elements
diff --git a/src/buildstream/_loader/metaelement.py b/src/buildstream/_loader/metaelement.py
index 45eb6f4d0..8214e303d 100644
--- a/src/buildstream/_loader/metaelement.py
+++ b/src/buildstream/_loader/metaelement.py
@@ -48,12 +48,12 @@ class MetaElement():
         self.kind = kind
         self.provenance = provenance
         self.sources = sources
-        self.config = config or _yaml.new_empty_node()
-        self.variables = variables or _yaml.new_empty_node()
-        self.environment = environment or _yaml.new_empty_node()
+        self.config = config or _yaml.Node.from_dict({})
+        self.variables = variables or _yaml.Node.from_dict({})
+        self.environment = environment or _yaml.Node.from_dict({})
         self.env_nocache = env_nocache or []
-        self.public = public or _yaml.new_empty_node()
-        self.sandbox = sandbox or _yaml.new_empty_node()
+        self.public = public or _yaml.Node.from_dict({})
+        self.sandbox = sandbox or _yaml.Node.from_dict({})
         self.build_dependencies = []
         self.dependencies = []
         self.first_pass = first_pass
diff --git a/src/buildstream/_projectrefs.py b/src/buildstream/_projectrefs.py
index c3e669c81..a46765250 100644
--- a/src/buildstream/_projectrefs.py
+++ b/src/buildstream/_projectrefs.py
@@ -87,7 +87,7 @@ class ProjectRefs():
         # Ensure we create our toplevel entry point on the fly here
         for node in [self._toplevel_node, self._toplevel_save]:
             if 'projects' not in node:
-                node['projects'] = _yaml.new_empty_node(ref_node=node)
+                node['projects'] = {}
 
     # lookup_ref()
     #
diff --git a/src/buildstream/_yaml.pyx b/src/buildstream/_yaml.pyx
index b717b2eb3..b67227d7b 100644
--- a/src/buildstream/_yaml.pyx
+++ b/src/buildstream/_yaml.pyx
@@ -71,7 +71,11 @@ cdef class Node:
 
     @classmethod
     def from_dict(cls, dict value):
-        return _new_node_from_dict(value, Node(None, _SYNTHETIC_FILE_INDEX, 0, next_synthetic_counter()))
+        if value:
+            return _new_node_from_dict(value, Node(None, _SYNTHETIC_FILE_INDEX, 0, next_synthetic_counter()))
+        else:
+            # We got an empty dict, we can shortcut
+            return MappingNode({}, _SYNTHETIC_FILE_INDEX, 0, next_synthetic_counter())
 
     cdef bint _walk_find(self, Node target, list path) except *:
         raise NotImplementedError()
@@ -1137,26 +1141,6 @@ def new_synthetic_file(str filename, object project=None):
     return node
 
 
-# new_empty_node()
-#
-# Args:
-#    ref_node (Node): Optional node whose provenance should be referenced
-#
-# Returns
-#    (Node): A new empty YAML mapping node
-#
-def new_empty_node(Node ref_node=None):
-    if ref_node is not None:
-        return MappingNode({}, ref_node.file_index, ref_node.line, next_synthetic_counter())
-    else:
-        return MappingNode({}, _SYNTHETIC_FILE_INDEX, 0, 0)
-
-
-# FIXME: we should never need that
-def new_empty_list_node():
-    return SequenceNode([], _SYNTHETIC_FILE_INDEX, 0, 0)
-
-
 # new_node_from_dict()
 #
 # Args:
diff --git a/src/buildstream/element.py b/src/buildstream/element.py
index 770f5df42..280eeb8f1 100644
--- a/src/buildstream/element.py
+++ b/src/buildstream/element.py
@@ -2515,7 +2515,7 @@ class Element(Plugin):
         # Defaults are loaded once per class and then reused
         #
         if cls.__defaults is None:
-            defaults = _yaml.new_empty_node()
+            defaults = _yaml.Node.from_dict({})
 
             if plugin_conf is not None:
                 # Load the plugin's accompanying .yaml file if one was provided
@@ -2550,7 +2550,7 @@ class Element(Plugin):
         default_env = cls.__defaults.get_mapping("environment", default={})
 
         if meta.is_junction:
-            environment = _yaml.new_empty_node()
+            environment = _yaml.Node.from_dict({})
         else:
             environment = project.base_environment.copy()
 
diff --git a/tests/internals/yaml.py b/tests/internals/yaml.py
index 69f29a573..3f6ef6cc9 100644
--- a/tests/internals/yaml.py
+++ b/tests/internals/yaml.py
@@ -521,6 +521,6 @@ def test_node_find_target_fails(datafiles):
                             "traversal.yaml")
     loaded = _yaml.load(filename, copy_tree=True)
 
-    brand_new = _yaml.new_empty_node()
+    brand_new = _yaml.Node.from_dict({})
 
     assert loaded._find(brand_new) is None