[RFC/PATCH] rename: warn user when we have turned off rename detection

[Jeff King <peff@peff.net>]

Signed-off-by: Jeff King <peff@peff.net>
---
This was another patch from late in the freeze period. It was in
response to a user getting confused about why rename detection wasn't
happening in a large merge. Is it appropriate to print this for every
rename we try? Or should it just be for merges?

Perhaps we should also bump the default limit from 100, which I think
was just arbitrarily chosen. I posted some numbers in:

  http://mid.gmane.org/20080211113516.GB6344@coredump.intra.peff.net

which imply that 200-400 is probably a more reasonable value. Thoughts?

 diffcore-rename.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/diffcore-rename.c b/diffcore-rename.c
index 3d37725..31941bc 100644
--- a/diffcore-rename.c
+++ b/diffcore-rename.c
@@ -468,10 +468,11 @@ void diffcore_rename(struct diff_options *options)
 	 */
 	if (rename_limit <= 0 || rename_limit > 32767)
 		rename_limit = 32767;
-	if (num_create > rename_limit && num_src > rename_limit)
-		goto cleanup;
-	if (num_create * num_src > rename_limit * rename_limit)
+	if ((num_create > rename_limit && num_src > rename_limit) ||
+	    (num_create * num_src > rename_limit * rename_limit)) {
+		warning("too many files, skipping inexact rename detection");
 		goto cleanup;
+	}
 
 	mx = xmalloc(sizeof(*mx) * num_create * num_src);
 	for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
-- 
1.5.4.3.422.g55194