Refactor: Lazily instantiate ProvenanceInformation objectstristan/lazy-provenance

As a rule, throughout the codebase we should not be using internal
ProvenanceInformation objects in our APIs, but rather Node objects.

This is because ProvenanceInformation is generated on the fly from
a Node object, and it is needlessly expensive to instantiate one before
it is absolutely needed.

This patch unilaterally fixes the codebase to pass `provenance_node`
Node objects around as arguments rather than `provenance` ProvenanceInformation
objects.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/buildstream/types.py b/src/buildstream/types.py
index 48dd5de6d..a5cf7afb8 100644
--- a/src/buildstream/types.py
+++ b/src/buildstream/types.py
@@ -280,14 +280,14 @@ class _PipelineSelection(FastEnum):
 #
 # Args:
 #    project (Project): The project instance
-#    provenance (ProvenanceInformation): The provenance information, if any
+#    provenance_node (Node): The provenance information, if any
 #    duplicates (list): List of project descriptions which declared this project as a duplicate
 #    internal (list): List of project descriptions which declared this project as internal
 #
 class _ProjectInformation:
-    def __init__(self, project, provenance, duplicates, internal):
+    def __init__(self, project, provenance_node, duplicates, internal):
         self.project = project
-        self.provenance = provenance
+        self.provenance = provenance_node.get_provenance() if provenance_node else None
         self.duplicates = duplicates
         self.internal = internal