diff --follow: do not waste cycles while recursing
The "--follow" logic is called from diff_tree_sha1() function, but the
input trees to diff_tree_sha1() are not necessarily the top-level trees
(compare_tree_entry() calls it while it recursively descends into
subtrees). When a newly created path lives in somewhere deep in the
source hierarchy, e.g. "platform/", but the rename source is in a totally
different place in the destination hierarchy, e.g. "lang-api/src/com/...",
running "try_to_find_renames()" while base is set to "platform/" is a
wasted call.
We only need to run the rename following at the very top level.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/tree-diff.c b/tree-diff.c
index 1fb3e94..5b68c08 100644
--- a/tree-diff.c
+++ b/tree-diff.c
@@ -412,7 +412,7 @@
init_tree_desc(&t1, tree1, size1);
init_tree_desc(&t2, tree2, size2);
retval = diff_tree(&t1, &t2, base, opt);
- if (DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename()) {
+ if (!*base && DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename()) {
init_tree_desc(&t1, tree1, size1);
init_tree_desc(&t2, tree2, size2);
try_to_follow_renames(&t1, &t2, base, opt);
