Need help with checking out gerrit review

[srikanthpailla]

Hi,

I am struggling to get the code working for checking out gerrit review.

`

class Git:

  def __init__(self, url: str, authcb: str, committer: str, workdir: Optional[str] = None) -> None:
      if not workdir:
          temp_git_dir = tempfile.mkdtemp(prefix="artcis_ci_lib_")
          dirname = hashlib.sha256(url.encode("utf-8")).hexdigest()
          self._workdir = os.path.join(temp_git_dir, dirname)
      else:
          self._workdir = workdir

      self._authentication_callback = authcb
      self._committer = committer

      logger.info("Checking out %s to %s...", url, self._workdir)

      self._repo = init_repository(self._workdir)
      self._remote = self._repo.remotes.create("origin", url)  # type: ignore

      logger.debug("TODO: install sig handler that removes %s on exit", self._workdir)

  @property
  def workdir(self) -> str:
      return self._workdir

  def fetch_and_checkout(self, remote_ref: str, retries: int = 8) -> TransferProgress:
      for i in range(1, retries + 1):
          try:
              progress = self._remote.fetch([remote_ref], callbacks=self._authentication_callback)  # type: ignore
              for _ in range(1800):
                  sleep(0.1)
                  if progress.received_objects == progress.total_objects:
                      break
              if progress.received_objects != progress.total_objects:
                  raise TimeoutError("Timeout while recieving objects")
              break
          except (TimeoutError, GitError) as err:
              if i >= retries:
                  raise err
              backoff_time = 2**i
              logger.error("Failed to fetch repository, retrying in %s seconds...", backoff_time)
              time.sleep(backoff_time)
              continue

      self._repo.checkout("FETCH_HEAD") 
      return progress  # type: ignore

`

This is working fine with branches, but when trying out with merged commit revision or commit revision from gerrit review, this code isn't working.

i get below error when trying to checkout gerrit review with revision or any revision which is already merged into master:
_pygit2.GitError: cannot fetch a specific object from the remote repository

Using pygit2==1.15.1

Could you please help to solve this issue.