[PATCH] builtin-revert: Make use of merge_recursive()

@@ -42,7 +42,7 @@ static struct tree *shift_tree_object(struct tree *one, struct tree *two)
  * - *(int *)commit->object.sha1 set to the virtual id.
  */
 
-static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
+struct commit *make_virtual_commit(struct tree *tree, const char *comment)
 {
 	struct commit *commit = xcalloc(1, sizeof(struct commit));
 	static unsigned virtual_id = 1;

@@ -11,6 +11,7 @@
 #include "cache-tree.h"
 #include "diff.h"
 #include "revision.h"
+#include "merge-recursive.h"
 
 /*
  * This implements the builtins revert and cherry-pick.

@@ -200,18 +201,27 @@ static void set_author_ident_env(const char *message)
 			sha1_to_hex(commit->object.sha1));
 }
 
-static int merge_recursive(const char *base_sha1,
-		const char *head_sha1, const char *head_name,
-		const char *next_sha1, const char *next_name)
+static int merge_recursive_helper(const unsigned char *base_sha1,
+		const unsigned char *head_sha1, const char *head_name,
+		const unsigned char *next_sha1, const char *next_name)
 {
-	char buffer[256];
-	const char *argv[6];
-	int i = 0;
-
-	sprintf(buffer, "GITHEAD_%s", head_sha1);
-	setenv(buffer, head_name, 1);
-	sprintf(buffer, "GITHEAD_%s", next_sha1);
-	setenv(buffer, next_name, 1);
+	int clean, index_fd;
+	struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
+	struct commit *result;
+	struct commit *head_commit, *next_commit;
+	struct object *head_object = parse_object(head_sha1);
+	struct commit_list *ca = NULL;
+
+	if (base_sha1) {
+		struct commit *base = lookup_commit_reference(base_sha1);
+		commit_list_insert(base, &ca);
+	}
+	if (head_object->type == OBJ_TREE)
+		head_commit = make_virtual_commit((struct tree *)head_object,
+						  head_name);
+	else
+		head_commit = (struct commit *)head_object;
+	next_commit = lookup_commit_reference(next_sha1);
 
 	/*
 	 * This three way merge is an interesting one.  We are at

@@ -219,15 +229,15 @@ static int merge_recursive(const char *base_sha1,
 	 * and $prev on top of us (when reverting), or the change between
 	 * $prev and $commit on top of us (when cherry-picking or replaying).
 	 */
-	argv[i++] = "merge-recursive";
-	if (base_sha1)
-		argv[i++] = base_sha1;
-	argv[i++] = "--";
-	argv[i++] = head_sha1;
-	argv[i++] = next_sha1;
-	argv[i++] = NULL;
-
-	return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
+	index_fd = hold_locked_index(lock, 1);
+	clean = merge_recursive(head_commit, next_commit,
+				head_name, next_name, ca, &result);
+	if (active_cache_changed &&
+			(write_cache(index_fd, active_cache, active_nr) ||
+			 commit_locked_index(lock)))
+		die("Unable to write index.");
+
+	return clean ? 0 : 1;
 }
 
 static char *help_msg(const unsigned char *sha1)

@@ -373,10 +383,8 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 		}
 	}
 
-	if (merge_recursive(base == NULL ?
-				NULL : sha1_to_hex(base->object.sha1),
-				sha1_to_hex(head), "HEAD",
-				sha1_to_hex(next->object.sha1), oneline) ||
+	if (merge_recursive_helper(base == NULL ? NULL : base->object.sha1,
+				   head, "HEAD", next->object.sha1, oneline) ||
 			write_cache_as_tree(head, 0, NULL)) {
 		add_to_msg("\nConflicts:\n\n");
 		read_cache();

@@ -1,6 +1,8 @@
 #ifndef MERGE_RECURSIVE_H
 #define MERGE_RECURSIVE_H
 
+extern struct commit *make_virtual_commit(struct tree *tree,
+					  const char *comment);
 int merge_recursive(struct commit *h1,
 		    struct commit *h2,
 		    const char *branch1,