commit 11d7587ef5019e3735f6ec20c43f580eb5c8a94e
from: Stefan Sperling <stsp@stsp.name>
date: Sat Jan 04 17:57:01 2020 UTC

replace commit graph's head_node pointer with a local variable

commit - ee780d5ce8c335e430804438c35eb48564ec0afb
commit + 11d7587ef5019e3735f6ec20c43f580eb5c8a94e
blob - c4649f5b6f357fc0bf48d47dad38c58b413f3849
blob + 3547daee92b9b6e429ebe95b6bfa67382fe47e83
--- lib/commit_graph.c
+++ lib/commit_graph.c
@@ -59,9 +59,6 @@ struct got_commit_graph_branch_tip {
 struct got_commit_graph {
 	/* The set of all commits we have traversed. */
 	struct got_object_idset *node_ids;
-
-	/* The commit at which traversal began (youngest commit in node_ids). */
-	struct got_commit_graph_node *head_node;
 
 	int flags;
 #define GOT_COMMIT_GRAPH_FIRST_PARENT_TRAVERSAL		0x01
@@ -388,6 +385,7 @@ got_commit_graph_open(struct got_commit_graph **graph,
 	const struct got_error *err = NULL;
 	struct got_commit_object *commit;
 	int changed, branch_done;
+	struct got_commit_graph_node *node;
 
 	*graph = NULL;
 
@@ -414,10 +412,10 @@ got_commit_graph_open(struct got_commit_graph **graph,
 	if (first_parent_traversal)
 		(*graph)->flags |= GOT_COMMIT_GRAPH_FIRST_PARENT_TRAVERSAL;
 
-	err = add_node(&(*graph)->head_node, &changed, &branch_done, *graph,
+	err = add_node(&node, &changed, &branch_done, *graph,
 	    commit_id, commit, NULL, repo);
 	if (err == NULL) {
-		err = advance_branch(*graph, (*graph)->head_node, commit_id,
+		err = advance_branch(*graph, node, commit_id,
 		    commit, repo);
 	}
 	got_object_commit_close(commit);