sequencer: change the way skip_unnecessary_picks() returns its result

Instead of skip_unnecessary_picks() printing its result to stdout, it
returns it into a struct object_id, as the rewrite of complete_action()
(to come in the next commit) will need it.

rebase--helper then is modified to fit this change.

Signed-off-by: Alban Gruin <alban.gruin@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/rebase--helper.c

@@ -90,8 +90,14 @@ int cmd_rebase__helper(int argc, const char **argv, const char *prefix)
 		return !!transform_todos(flags);
 	if (command == CHECK_TODO_LIST && argc == 1)
 		return !!check_todo_list();
-	if (command == SKIP_UNNECESSARY_PICKS && argc == 1)
-		return !!skip_unnecessary_picks();
+	if (command == SKIP_UNNECESSARY_PICKS && argc == 1) {
+		struct object_id oid;
+		int ret = skip_unnecessary_picks(&oid);
+
+		if (!ret)
+			puts(oid_to_hex(&oid));
+		return !!ret;
+	}
 	if (command == REARRANGE_SQUASH && argc == 1)
 		return !!rearrange_squash();
 	if (command == ADD_EXEC && argc == 2)

sequencer.c

@@ -4416,17 +4416,17 @@ static int rewrite_file(const char *path, const char *buf, size_t len)
 }
 
 /* skip picking commits whose parents are unchanged */
-int skip_unnecessary_picks(void)
+int skip_unnecessary_picks(struct object_id *output_oid)
 {
 	const char *todo_file = rebase_path_todo();
 	struct strbuf buf = STRBUF_INIT;
 	struct todo_list todo_list = TODO_LIST_INIT;
-	struct object_id onto_oid, *oid = &onto_oid, *parent_oid;
+	struct object_id *parent_oid;
 	int fd, i;
 
 	if (!read_oneliner(&buf, rebase_path_onto(), 0))
 		return error(_("could not read 'onto'"));
-	if (get_oid(buf.buf, &onto_oid)) {
+	if (get_oid(buf.buf, output_oid)) {
 		strbuf_release(&buf);
 		return error(_("need a HEAD to fixup"));
 	}
@@ -4456,9 +4456,9 @@ int skip_unnecessary_picks(void)
 		if (item->commit->parents->next)
 			break; /* merge commit */
 		parent_oid = &item->commit->parents->item->object.oid;
-		if (hashcmp(parent_oid->hash, oid->hash))
+		if (hashcmp(parent_oid->hash, output_oid->hash))
 			break;
-		oid = &item->commit->object.oid;
+		oidcpy(output_oid, &item->commit->object.oid);
 	}
 	if (i > 0) {
 		int offset = get_item_line_offset(&todo_list, i);
@@ -4487,11 +4487,10 @@ int skip_unnecessary_picks(void)
 
 		todo_list.current = i;
 		if (is_fixup(peek_command(&todo_list, 0)))
-			record_in_rewritten(oid, peek_command(&todo_list, 0));
+			record_in_rewritten(output_oid, peek_command(&todo_list, 0));
 	}
 
 	todo_list_release(&todo_list);
-	printf("%s\n", oid_to_hex(oid));
 
 	return 0;
 }

sequencer.h

@@ -91,7 +91,7 @@ int sequencer_add_exec_commands(const char *command);
 int transform_todos(unsigned flags);
 enum missing_commit_check_level get_missing_commit_check_level(void);
 int check_todo_list(void);
-int skip_unnecessary_picks(void);
+int skip_unnecessary_picks(struct object_id *output_oid);
 int rearrange_squash(void);
 
 extern const char sign_off_header[];