Support loading 'workspace'-kind sources

Add the workspace-kind source to the sources manually to prevent a user
incorrectly loading the source plugin.

2 files changed, 43 insertions, 7 deletions

diff --git a/src/buildstream/_loader/loader.py b/src/buildstream/_loader/loader.py
index 5599c8b71..6a8db892f 100644
--- a/src/buildstream/_loader/loader.py
+++ b/src/buildstream/_loader/loader.py
@@ -438,17 +438,38 @@ class Loader():
         sources = node.get_sequence(Symbol.SOURCES, default=[])
         element_kind = node.get_str(Symbol.KIND)
 
-        for index, source in enumerate(sources):
-            kind = source.get_str(Symbol.KIND)
-            del source[Symbol.KIND]
+        def make_metasource(_index, _source, skip_workspace=True):
+            kind = _source.get_str(Symbol.KIND)
+            # the workspace source plugin cannot be used unless the element is workspaced
+            if kind == 'workspace' and skip_workspace:
+                return None
+
+            del _source[Symbol.KIND]
 
             # Directory is optional
-            directory = source.get_str(Symbol.DIRECTORY, default=None)
+            directory = _source.get_str(Symbol.DIRECTORY, default=None)
             if directory:
-                del source[Symbol.DIRECTORY]
+                del _source[Symbol.DIRECTORY]
+
+            return MetaSource(element.name, _index, element_kind, kind, _source, directory)
 
-            meta_source = MetaSource(element.name, index, element_kind, kind, source, directory)
-            meta_sources.append(meta_source)
+        for index, source in enumerate(sources):
+            meta_source = make_metasource(index, source)
+            if meta_source:
+                meta_sources.append(meta_source)
+
+        # if there's a workspace for this element then just append a dummy workspace
+        # metasources. When sources are instantiated, the workspace will own the
+        # element sources. These can then be referred to when resetting or similar operations.
+        workspace = self._context.get_workspaces().get_workspace(element.name)
+        if workspace:
+            workspace_node = {'kind': 'workspace'}
+            workspace_node['path'] = workspace.get_absolute_path()
+            workspace_node['ref'] = str(workspace.to_dict().get('last_successful', 'ignored'))
+            sources.append(workspace_node)
+            meta_source = make_metasource(len(sources), sources.mapping_at(-1), False)
+            if meta_source:
+                meta_sources.append(meta_source)
 
         meta_element = MetaElement(self.project, element.name, element_kind,
                                    elt_provenance, meta_sources,
diff --git a/src/buildstream/element.py b/src/buildstream/element.py
index 044b97458..711723ebe 100644
--- a/src/buildstream/element.py
+++ b/src/buildstream/element.py
@@ -1023,6 +1023,9 @@ class Element(Plugin):
         element = meta.project.create_element(meta, first_pass=meta.first_pass)
         cls.__instantiated_elements[meta] = element
 
+        # do the metasources include a workspace source?
+        _workspace_source = None
+
         # Instantiate sources and generate their keys
         for meta_source in meta.sources:
             meta_source.first_pass = meta.is_junction
@@ -1030,12 +1033,24 @@ class Element(Plugin):
                                                 first_pass=meta.first_pass)
 
             redundant_ref = source._load_ref()
+
+            if meta_source.kind == 'workspace':
+                _workspace_source = source
+                continue
+
             element.__sources.append(source)
 
             # Collect redundant refs which occurred at load time
             if redundant_ref is not None:
                 cls.__redundant_source_refs.append((source, redundant_ref))
 
+        # workspace handling: if the metasources included a workspace source, then
+        # this should replace the element.__sources and should in turn own those sources
+        # directly
+        if _workspace_source is not None:
+            _workspace_source.set_element_sources(element.__sources)
+            element.__sources = [_workspace_source]
+
         # Instantiate dependencies
         for meta_dep in meta.dependencies:
             dependency = Element._new_from_meta(meta_dep, task)