treewide: rename tree to maybe_tree

Using the commit-graph file to walk commit history removes the large
cost of parsing commits during the walk. This exposes a performance
issue: lookup_tree() takes a large portion of the computation time,
even when Git never uses those trees.

In anticipation of lazy-loading these trees, rename the 'tree' member
of struct commit to 'maybe_tree'. This serves two purposes: it hints
at the future role of possibly being NULL even if the commit has a
valid tree, and it allows for unambiguous transformation from simple
member access (i.e. commit->maybe_tree) to method access.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/walker.c b/walker.c
index dffb9c8..1d5f305 100644
--- a/walker.c
+++ b/walker.c
@@ -87,7 +87,7 @@ static int process_commit(struct walker *walker, struct commit *commit)
 	walker_say(walker, "walk %s\n", oid_to_hex(&commit->object.oid));
 
 	if (walker->get_tree) {
-		if (process(walker, &commit->tree->object))
+		if (process(walker, &commit->maybe_tree->object))
 			return -1;
 		if (!walker->get_all)
 			walker->get_tree = 0;