diff options
Diffstat (limited to 'src/buildstream/_loader/loader.py')
| -rw-r--r-- | src/buildstream/_loader/loader.py | 119 |
1 files changed, 79 insertions, 40 deletions
diff --git a/src/buildstream/_loader/loader.py b/src/buildstream/_loader/loader.py index e63dd6c57..76d5eef82 100644 --- a/src/buildstream/_loader/loader.py +++ b/src/buildstream/_loader/loader.py @@ -46,9 +46,10 @@ from .._message import Message, MessageType # Args: # project (Project): The toplevel Project object # parent (Loader): A parent Loader object, in the case this is a junctioned Loader +# provenance (ProvenanceInformation): The provenance of the reference to this project's junction # class Loader: - def __init__(self, project, *, parent=None): + def __init__(self, project, *, parent=None, provenance=None): # Ensure we have an absolute path for the base directory basedir = project.element_path @@ -60,6 +61,7 @@ class Loader: # self.load_context = project.load_context # The LoadContext self.project = project # The associated Project + self.provenance = provenance # The provenance of whence this loader was instantiated self.loaded = None # The number of loaded Elements # @@ -73,9 +75,14 @@ class Loader: self._meta_elements = {} # Dict of resolved meta elements by name self._elements = {} # Dict of elements self._loaders = {} # Dict of junction loaders + self._loader_search_provenances = {} # Dictionary of provenances of ongoing child loader searches self._includes = Includes(self, copy_tree=True) + assert project.name is not None + + self.load_context.register_loader(self) + # load(): # # Loads the project based on the parameters given to the constructor @@ -163,12 +170,27 @@ class Loader: # Returns: # (Loader): loader for sub-project # - def get_loader(self, name, provenance, *, level=0): + def get_loader(self, name, provenance): junction_path = name.split(":") loader = self + circular_provenance = self._loader_search_provenances.get(name, None) + if circular_provenance: + detail = None + if circular_provenance is not provenance: + detail = "Already searching for '{}' at: {}".format(name, circular_provenance) + raise LoadError( + "{}: Circular reference while searching for '{}'".format(provenance, name), + LoadErrorReason.CIRCULAR_REFERENCE, + detail=detail, + ) + + self._loader_search_provenances[name] = provenance + for junction_name in junction_path: - loader = loader._get_loader(junction_name, provenance, level=level) + loader = loader._get_loader(junction_name, provenance) + + del self._loader_search_provenances[name] return loader @@ -514,6 +536,40 @@ class Loader: return self._meta_elements[top_element.name] + # _search_for_override(): + # + # Search parent projects for an overridden subproject to replace this junction. + # + # Args: + # filename (str): Junction name + # + def _search_for_override(self, filename): + loader = self + override_path = filename + + # Collect any overrides to this junction in the ancestry + # + overriding_loaders = [] + while loader._parent: + junction = loader.project.junction + override_filename, override_provenance = junction.overrides.get(override_path, (None, None)) + if override_filename: + overriding_loaders.append((loader, override_filename, override_provenance)) + + override_path = junction.name + ":" + override_path + loader = loader._parent + + # If there are any overriding loaders, use the highest one in + # the ancestry to lookup the loader for this project. + # + if overriding_loaders: + loader, filename, provenance = overriding_loaders[-1] + return loader._parent.get_loader(filename, provenance) + + # No overrides were found in the ancestry + # + return None + # _get_loader(): # # Return loader for specified junction @@ -526,7 +582,7 @@ class Loader: # # Returns: A Loader or None if specified junction does not exist # - def _get_loader(self, filename, provenance, *, level=0): + def _get_loader(self, filename, provenance): loader = None provenance_str = "" if provenance is not None: @@ -534,43 +590,21 @@ class Loader: # return previously determined result if filename in self._loaders: - loader = self._loaders[filename] - - if loader is None: - # do not allow junctions with the same name in different - # subprojects - raise LoadError( - "{}Conflicting junction {} in subprojects, define junction in {}".format( - provenance_str, filename, self.project.name - ), - LoadErrorReason.CONFLICTING_JUNCTION, - ) - - return loader + return self._loaders[filename] - if self._parent: - # junctions in the parent take precedence over junctions defined - # in subprojects - loader = self._parent._get_loader(filename, level=level + 1, provenance=provenance) - if loader: - self._loaders[filename] = loader - return loader - - try: - self._load_file(filename, provenance=provenance) - except LoadError as e: - if e.reason != LoadErrorReason.MISSING_FILE: - # other load error - raise - - if level == 0: - # junction element not found in this or ancestor projects - raise + # + # Search the ancestry for an overridden loader to use in place + # of using the locally defined junction. + # + override_loader = self._search_for_override(filename) + if override_loader: + self._loaders[filename] = override_loader + return override_loader - # mark junction as not available to allow detection of - # conflicting junctions in subprojects - self._loaders[filename] = None - return None + # + # Load the junction file + # + self._load_file(filename, provenance) # At this point we've loaded the LoadElement load_element = self._elements[filename] @@ -668,7 +702,12 @@ class Loader: from .._project import Project # pylint: disable=cyclic-import project = Project( - project_dir, self.load_context.context, junction=element, parent_loader=self, search_for_project=False, + project_dir, + self.load_context.context, + junction=element, + parent_loader=self, + search_for_project=False, + provenance=provenance, ) except LoadError as e: if e.reason == LoadErrorReason.MISSING_PROJECT_CONF: |