private void updateSubmodules()

in java/com/googlesource/gerrit/plugins/supermanifest/JiriUpdater.java [62:201]
117 lines of code
27 McCabe index (conditional complexity)

  private void updateSubmodules(
      Repository repo,
      String targetRef,
      URI targetURI,
      JiriProjects projects,
      GerritRemoteReader reader)
      throws IOException, GitAPIException {
    DirCache index = DirCache.newInCore();
    DirCacheBuilder builder = index.builder();
    ObjectInserter inserter = repo.newObjectInserter();
    try (RevWalk rw = new RevWalk(repo)) {
      Config cfg = new Config();
      projects.sortByPath();
      String parent = null;
      for (JiriProjects.Project proj : projects.getProjects()) {
        String path = proj.getPath();
        String nameUri = proj.getRemote();
        if (parent != null) {
          String p1 = StringUtil.stripAndAddCharsAtEnd(path, "/");
          String p2 = StringUtil.stripAndAddCharsAtEnd(parent, "/");
          if (p1.startsWith(p2)) {
            warn(
                "Skipping project %s(%s) as git doesn't support nested submodules",
                proj.getName(), path);
            continue;
          }
        }

        ObjectId objectId;
        String ref = proj.getRef();

        if (ObjectId.isId(ref)) {
          objectId = ObjectId.fromString(ref);
        } else {
          objectId = reader.sha1(nameUri, ref);
          if (objectId == null) {
            warn("failed to get ref '%s' for '%s', skipping", ref, nameUri);
            continue;
          }
        }

        // can be branch, tag or SHA1 (objectId)
        if (!ObjectId.isId(ref)) {
          // "branch" field is only for non-tag references.
          // Keep tags in "ref" field as hint for other tools.
          String field = ref.startsWith(REFS_TAGS) ? "ref" : "branch";
          cfg.setString("submodule", path, field, ref);
        }

        if (proj.getHistorydepth() > 0) {
          cfg.setBoolean("submodule", path, "shallow", true);
          if (proj.getHistorydepth() != 1) {
            warn(
                "Project %s(%s) has historydepth other than 1. Submodule only support shallow of depth 1.",
                proj.getName(), proj.getPath());
          }
        }

        URI submodUrl = URI.create(nameUri);

        // check if repo is local by matching hostnames
        String repoName = submodUrl.getPath();
        while (repoName.startsWith("/")) {
          repoName = repoName.substring(1);
        }
        URI localURI = getLocalURI(repoName);
        if (localURI != null && localURI.getHost().equals(submodUrl.getHost())) {
          submodUrl = relativize(targetURI, URI.create(repoName));
        }

        cfg.setString("submodule", path, "path", path);
        cfg.setString("submodule", path, "url", submodUrl.toString());

        // create gitlink
        DirCacheEntry dcEntry = new DirCacheEntry(path);
        dcEntry.setObjectId(objectId);
        dcEntry.setFileMode(FileMode.GITLINK);
        builder.add(dcEntry);
        parent = path;
      }

      String content = cfg.toText();

      // create a new DirCacheEntry for .gitmodules file.
      final DirCacheEntry dcEntry = new DirCacheEntry(Constants.DOT_GIT_MODULES);
      ObjectId objectId = inserter.insert(Constants.OBJ_BLOB, content.getBytes(UTF_8));
      dcEntry.setObjectId(objectId);
      dcEntry.setFileMode(FileMode.REGULAR_FILE);
      builder.add(dcEntry);

      builder.finish();
      ObjectId treeId = index.writeTree(inserter);

      // Create a Commit object, populate it and write it
      ObjectId headId = repo.resolve(targetRef + "^{commit}");
      CommitBuilder commit = new CommitBuilder();
      commit.setTreeId(treeId);
      if (headId != null) commit.setParentIds(headId);
      PersonIdent author =
          new PersonIdent(
              serverIdent.getName(),
              serverIdent.getEmailAddress(),
              new Date(),
              serverIdent.getTimeZone());
      commit.setAuthor(author);
      commit.setCommitter(author);
      commit.setMessage(RepoText.get().repoCommitMessage);

      ObjectId commitId = inserter.insert(commit);
      inserter.flush();

      RefUpdate ru = repo.updateRef(targetRef);
      ru.setNewObjectId(commitId);
      ru.setExpectedOldObjectId(headId != null ? headId : ObjectId.zeroId());
      Result rc = ru.update(rw);

      switch (rc) {
        case NEW:
        case FORCED:
        case FAST_FORWARD:
          // Successful. Do nothing.
          break;
        case REJECTED:
        case LOCK_FAILURE:
          throw new ConcurrentRefUpdateException(
              MessageFormat.format(JGitText.get().cannotLock, targetRef), ru.getRef(), rc);
        case IO_FAILURE:
        case NOT_ATTEMPTED:
        case NO_CHANGE:
        case REJECTED_CURRENT_BRANCH:
        case REJECTED_MISSING_OBJECT:
        case REJECTED_OTHER_REASON:
        case RENAMED:
        default:
          throw new JGitInternalException(
              MessageFormat.format(
                  JGitText.get().updatingRefFailed, targetRef, commitId.name(), rc));
      }
    }
  }