[PATCH] diff: make -M -C mean the same as -C -M

[Mike Hommey <mh@glandium.org>]

While -C implies -M, it is quite common to see both on example command lines
here and there. The unintuitive thing is that if -M appears after -C, then
copy detection is turned off because of how the command line arguments are
handled.

Change this so that when both -C and -M appear, whatever their order, copy
detection is on.

Signed-off-by: Mike Hommey <mh@glandium.org>
---

Interestingly, I even found mentions of -C -M in this order for benchmarks,
on this very list (see 6555655.XSJ9EnW4BY@mako).

 diff.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/diff.c b/diff.c
index d1bd534..9081fd8 100644
--- a/diff.c
+++ b/diff.c
@@ -3670,7 +3670,8 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 		 !strcmp(arg, "--find-renames")) {
 		if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
 			return error("invalid argument to -M: %s", arg+2);
-		options->detect_rename = DIFF_DETECT_RENAME;
+		if (options->detect_rename != DIFF_DETECT_COPY)
+			options->detect_rename = DIFF_DETECT_RENAME;
 	}
 	else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
 		options->irreversible_delete = 1;
-- 
2.2.2.2.g806f5e2.dirty