coccinelle: convert hashcpy() with null_sha1 to hashclr()

hashcpy with null_sha1 as the source is equivalent to hashclr.  In
addition to being simpler, using hashclr may give the compiler a chance
to optimize better.  Convert instances of hashcpy with the source
argument of null_sha1 to hashclr.

This transformation was implemented using the following semantic patch:

@@
expression E1;
@@
-hashcpy(E1, null_sha1);
+hashclr(E1);

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 3 insertions, 3 deletions

diff --git a/builtin/merge.c b/builtin/merge.c
index b555a1bf9c..a9b99c9ffc 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -1530,7 +1530,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	     * Stash away the local changes so that we can try more than one.
 	     */
 	    save_state(stash))
-		hashcpy(stash, null_sha1);
+		hashclr(stash);
 
 	for (i = 0; i < use_strategies_nr; i++) {
 		int ret;
diff --git a/builtin/unpack-objects.c b/builtin/unpack-objects.c
index 875e7ed998..172470bf24 100644
--- a/builtin/unpack-objects.c
+++ b/builtin/unpack-objects.c
@@ -355,7 +355,7 @@ static void unpack_delta_entry(enum object_type type, unsigned long delta_size,
 			return; /* we are done */
 		else {
 			/* cannot resolve yet --- queue it */
-			hashcpy(obj_list[nr].sha1, null_sha1);
+			hashclr(obj_list[nr].sha1);
 			add_delta_to_list(nr, base_sha1, 0, delta_data, delta_size);
 			return;
 		}
@@ -406,7 +406,7 @@ static void unpack_delta_entry(enum object_type type, unsigned long delta_size,
 			 * The delta base object is itself a delta that
 			 * has not been resolved yet.
 			 */
-			hashcpy(obj_list[nr].sha1, null_sha1);
+			hashclr(obj_list[nr].sha1);
 			add_delta_to_list(nr, null_sha1, base_offset, delta_data, delta_size);
 			return;
 		}