+int upgrade_repository_format(int target_version)
+{
+ struct strbuf sb = STRBUF_INIT;
+ struct strbuf err = STRBUF_INIT;
+ struct strbuf repo_version = STRBUF_INIT;
+ struct repository_format repo_fmt = REPOSITORY_FORMAT_INIT;
+
+ strbuf_git_common_path(&sb, the_repository, "config");
+ read_repository_format(&repo_fmt, sb.buf);
+ strbuf_release(&sb);
+
+ if (repo_fmt.version >= target_version)
+ return 0;
+
+ if (verify_repository_format(&repo_fmt, &err) < 0 ||
+ (!repo_fmt.version && repo_fmt.has_extensions)) {
+ warning("unable to upgrade repository format from %d to %d: %s",
+ repo_fmt.version, target_version, err.buf);
+ strbuf_release(&err);
+ return -1;
+ }
+
+ strbuf_addf(&repo_version, "%d", target_version);
+ git_config_set("core.repositoryformatversion", repo_version.buf);
+ strbuf_release(&repo_version);
+ return 1;
+}
+