_stream.py: Opened workspaces store the project that opened them

buildstream/_stream.py

@@ -550,6 +550,8 @@ class Stream():
         # So far this function has tried to catch as many issues as possible with out making any changes
         # Now it dose the bits that can not be made atomic.
         targetGenerator = zip(elements, expanded_directories)
+        workspace_project_cache = self._context.get_workspace_project_cache()
+        project = self._context.get_toplevel_project()
         for target, directory in targetGenerator:
             self._message(MessageType.INFO, "Creating workspace for element {}"
                           .format(target.name))
@@ -574,6 +576,10 @@ class Stream():
                 with target.timed_activity("Staging sources to {}".format(directory)):
                     target._open_workspace()
 
+            workspace_project = workspace_project_cache.add(directory, project.directory,
+                                                            target._get_full_name())
+            workspace_project.write()
+
             # Saving the workspace once it is set up means that if the next workspace fails to be created before
             # the configuration gets saved. The successfully created workspace still gets saved.
             workspaces.save_config()