[PATCH] builtin-commit: fix "git add x y && git commit y" committing x, too

@@ -100,6 +100,7 @@ static void update_callback(struct diff_queue_struct *q,
 		case DIFF_STATUS_UNMERGED:
 		case DIFF_STATUS_MODIFIED:
 		case DIFF_STATUS_TYPE_CHANGED:
+		case DIFF_STATUS_ADDED:
 			add_file_to_cache(path, verbose);
 			break;
 		case DIFF_STATUS_DELETED:

@@ -19,6 +19,7 @@
 #include "strbuf.h"
 #include "utf8.h"
 #include "parse-options.h"
+#include "unpack-trees.h"
 
 static const char * const builtin_commit_usage[] = {
 	"git-commit [options] [--] <filepattern>...",

@@ -77,6 +78,31 @@ static struct option builtin_commit_options[] = {
 	OPT_END()
 };
 
+static int reset_index_to_head(void)
+{
+	struct unpack_trees_options opts;
+	struct tree_desc tree_desc;
+	struct tree *tree;
+	unsigned char sha1[20];
+
+	/* ignore if it is an initial commit */
+	if (get_sha1("HEAD", sha1))
+		return 0;
+	tree = parse_tree_indirect(sha1);
+	if (!tree || parse_tree(tree))
+		return error("Could not get HEAD's tree");
+	init_tree_desc(&tree_desc, tree->buffer, tree->size);
+
+	memset(&opts, 0, sizeof(opts));
+	opts.index_only = 1;
+	opts.merge = 1;
+	opts.head_idx = 1;
+	opts.fn = oneway_merge;
+	if (unpack_trees(1, &tree_desc, &opts))
+		return error("Could not reset temporary index to HEAD");
+	return 0;
+}
+
 static char *prepare_index(const char **files, const char *prefix)
 {
 	int fd;

@@ -120,12 +146,14 @@ static char *prepare_index(const char **files, const char *prefix)
 			die("failed to read HEAD tree object");
 	}
 
+	if (reset_index_to_head())
+		die ("failed to reset temporary index to HEAD");
+
 	/* Use a lock file to garbage collect the temporary index file. */
 	next_index_lock = xmalloc(sizeof(*next_index_lock));
 	fd = hold_lock_file_for_update(next_index_lock,
 				       git_path("next-index-%d", getpid()), 1);
 	add_files_to_cache(verbose, prefix, files);
-	refresh_cache(REFRESH_QUIET);
 	if (write_cache(fd, active_cache, active_nr) || close(fd))
 		die("unable to write new_index file");
 

@@ -139,4 +139,14 @@ test_expect_success '--signoff' '
 	diff expect output
 '
 
+test_expect_success 'implicit --only only commits specified files' '
+	echo "tonight: " > take &&
+	echo "over the" > world &&
+	git add world take &&
+	test_tick &&
+	git commit -m partial world &&
+	git diff-tree HEAD^..HEAD -- take &&
+	! git diff-index --cached --exit-code HEAD -- take
+'
+
 test_done