public async function genCommitPatch()

in src/shipit/repo/ShipItRepoGIT.php [269:354]
66 lines of code
10 McCabe index (conditional complexity)

  public async function genCommitPatch(
    ShipItChangeset $patch,
    bool $do_submodules = true,
  ): Awaitable<string> {
    if (C\is_empty($patch->getDiffs())) {
      // This is an empty commit, which `git am` does not handle properly.
      await $this->genGitCommand(
        'commit',
        '--allow-empty',
        '--author',
        $patch->getAuthor(),
        '--date',
        (string)$patch->getTimestamp(),
        '-m',
        self::getCommitMessage($patch),
      );
      return await $this->genHEADSha();
    }

    $diff = self::renderPatch($patch);
    try {
      await $this->genGitPipeCommand(
        $diff,
        'am',
        '--keep-non-patch',
        '--keep-cr',
        '--committer-date-is-author-date',
      );
    } catch (ShipItRepoGITException $e) {
      // If we are trying to git am on a non-git repo, for example
      await $this->genGitCommand('am', '--abort');
      throw $e;
    } catch (ShipItRepoException $e) {
      await $this->genGitCommand('am', '--abort');
      throw $e;
    } catch (ShipItShellCommandException $e) {
      await $this->genGitCommand('am', '--abort');
      throw $e;
    }

    if ($do_submodules) {
      $submodules = await $this->genSubmodules();
    } else {
      $submodules = vec[];
    }
    foreach ($submodules as $submodule) {
      try {
        // @lint-ignore AWAIT_IN_LOOP We need to do this serially
        await $this->genPrepareSubmoduleForPatch($submodule);
      } catch (ShipItShellCommandException $e) {
        // HACK: try once again with GitHub HTTPS authentication.
        // Since most submodules in use don't need auth, it's least disruptive
        // to do this only when the first attempt fails.
        $url = $submodule['url'];
        $match = Regex\first_match(
          $url,
          re"@https://github.com/(?<org>[^\./]+)/(?<project>[^\./]+)[\./]?@",
        );
        if ($match is null) {
          throw $e;
        }
        // FIXME: FB-specific
        try {
          // @lint-ignore AWAIT_IN_LOOP We need to do this serially
          // @oss-disable: await FBGitHubUtils::genConfigureSubmodule(
            // @oss-disable: $match['org'],
            // @oss-disable: $match['project'],
            // @oss-disable: $this->getPath(),
            // @oss-disable: $submodule,
          // @oss-disable: );
          // @lint-ignore AWAIT_IN_LOOP We need to do this serially
          await $this->genPrepareSubmoduleForPatch($submodule);
        } finally {
          // Cleanup from submodule auth
          try {
            // @lint-ignore AWAIT_IN_LOOP We need to do this serially
            await $this->genGitCommand('restore', '.gitmodules');
          } catch (ShipItShellCommandException $_) {
          }
        }
      }
    }
    // DANGER ZONE!  Cleanup any removed submodules.
    await $this->genGitCommand('clean', '-f', '-f', '-d');
    return await $this->genHEADSha();
  }