[PATCH v2] merge-recursive: option to disable renames

["Felipe Gonçalves Assis" <felipeg.assis@gmail.com>]

The recursive strategy turns on rename detection by default. Add a
strategy option to disable rename detection even for exact renames.

Signed-off-by: Felipe Gonçalves Assis <felipegassis@gmail.com>
---

Following Hamano's review, this patch includes a strategy option "renames" and
simplifies the implementation.

Also note merge-recursive.c:492, where I forward detect_rename from the merge
options to the diff options, instead of hardcoding it to DIFF_DETECT_RENAME,
which could cause surprises in the future.

 Documentation/merge-strategies.txt |  9 +++++++++
 merge-recursive.c                  | 10 +++++++++-
 merge-recursive.h                  |  1 +
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/Documentation/merge-strategies.txt b/Documentation/merge-strategies.txt
index 7bbd19b..f794d23 100644
--- a/Documentation/merge-strategies.txt
+++ b/Documentation/merge-strategies.txt
@@ -81,6 +81,15 @@ no-renormalize;;
 	Disables the `renormalize` option.  This overrides the
 	`merge.renormalize` configuration variable.
 
+renames;;
+	Turn on rename detection.
+	This is the default.
+	See also linkgit:git-diff[1] `-M`.
+
+no-renames;;
+	Turn off rename detection.
+	See also linkgit:git-diff[1] `--no-renames`.
+
 rename-threshold=<n>;;
 	Controls the similarity threshold used for rename detection.
 	See also linkgit:git-diff[1] `-M`.
diff --git a/merge-recursive.c b/merge-recursive.c
index 8eabde2..2f9c40a 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -482,10 +482,13 @@ static struct string_list *get_renames(struct merge_options *o,
 	struct diff_options opts;
 
 	renames = xcalloc(1, sizeof(struct string_list));
+	if (!o->detect_rename)
+		return renames;
+
 	diff_setup(&opts);
 	DIFF_OPT_SET(&opts, RECURSIVE);
 	DIFF_OPT_CLR(&opts, RENAME_EMPTY);
-	opts.detect_rename = DIFF_DETECT_RENAME;
+	opts.detect_rename = o->detect_rename;
 	opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 			    o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 			    1000;
@@ -2039,6 +2042,7 @@ void init_merge_options(struct merge_options *o)
 	o->diff_rename_limit = -1;
 	o->merge_rename_limit = -1;
 	o->renormalize = 0;
+	o->detect_rename = DIFF_DETECT_RENAME;
 	merge_recursive_config(o);
 	if (getenv("GIT_MERGE_VERBOSITY"))
 		o->verbosity =
@@ -2088,6 +2092,10 @@ int parse_merge_opt(struct merge_options *o, const char *s)
 		o->renormalize = 1;
 	else if (!strcmp(s, "no-renormalize"))
 		o->renormalize = 0;
+	else if (!strcmp(s, "renames"))
+		o->detect_rename = DIFF_DETECT_RENAME;
+	else if (!strcmp(s, "no-renames"))
+		o->detect_rename = 0;
 	else if (skip_prefix(s, "rename-threshold=", &arg)) {
 		if ((o->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
 			return -1;
diff --git a/merge-recursive.h b/merge-recursive.h
index 9e090a3..52f0201 100644
--- a/merge-recursive.h
+++ b/merge-recursive.h
@@ -17,6 +17,7 @@ struct merge_options {
 	unsigned renormalize : 1;
 	long xdl_opts;
 	int verbosity;
+	int detect_rename;
 	int diff_rename_limit;
 	int merge_rename_limit;
 	int rename_score;
-- 
2.7.1.288.g6752e66