PollingFuture default timeout value object() incompatible with QueryJob typeguard in _reload_query_results

[gbmarc1]

google.api_core.future.polling.PollingFuture default timeout value object() incompatible with google.cloud.bigquery.job.query.QueryJob typeguard in _reload_query_results.

A refactor in google-api-core introduced the global _DEFAULT_VALUE in the PollingFuture class ->
here.
This change is incompatible with google-cloud-bigquery typeguard here and becomes invalid and enters the if context which results in a error on this line.

TypeError: unsupported operand type(s) for -: 'object' and 'float'

The typeguard is based on the fact that the default value is None and not object().

As discussed here with @vam-google,

The default value cannot be None and the previous behavior of api-core was a bug. The gist of it is the need to distinguish between infinite timeout (None) and not specified timeout (_DEFAULT_TIMEOUT).

Stack trace

/usr/local/lib/python3.9/site-packages/feast/infra/offline_stores/bigquery.py:583: in block_until_done
--
  | if bq_job.exception():
  | /usr/local/lib/python3.9/site-packages/google/api_core/future/polling.py:282: in exception
  | self._blocking_poll(timeout=timeout)
  | /usr/local/lib/python3.9/site-packages/google/cloud/bigquery/job/query.py:1245: in _blocking_poll
  | super(QueryJob, self)._blocking_poll(timeout=timeout, **kwargs)
  | /usr/local/lib/python3.9/site-packages/google/api_core/future/polling.py:137: in _blocking_poll
  | polling(self._done_or_raise)(retry=retry)
  | /usr/local/lib/python3.9/site-packages/google/api_core/retry.py:349: in retry_wrapped_func
  | return retry_target(
  | /usr/local/lib/python3.9/site-packages/google/api_core/retry.py:191: in retry_target
  | return target()
  | /usr/local/lib/python3.9/site-packages/google/cloud/bigquery/job/query.py:1358: in _done_or_raise
  | self._reload_query_results(retry=retry, timeout=transport_timeout)
  | _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
  |  
  | self = QueryJob<project=..., location=US, id=...>
  | retry = None, timeout = <object object at 0x7fa46677c5c0>
  |  
  | def _reload_query_results(
  | self, retry: "retries.Retry" = DEFAULT_RETRY, timeout: float = None
  | ):
  | """Refresh the cached query results.
  |  
  | Args:
  | retry (Optional[google.api_core.retry.Retry]):
  | How to retry the call that retrieves query results.
  | timeout (Optional[float]):
  | The number of seconds to wait for the underlying HTTP transport
  | before using ``retry``.
  | """
  | if self._query_results and self._query_results.complete:
  | return
  |  
  | # Since the API to getQueryResults can hang up to the timeout value
  | # (default of 10 seconds), set the timeout parameter to ensure that
  | # the timeout from the futures API is respected. See:
  | # https://github.com/GoogleCloudPlatform/google-cloud-python/issues/4135
  | timeout_ms = None
  | if self._done_timeout is not None:
  | # Subtract a buffer for context switching, network latency, etc.
  | >           api_timeout = self._done_timeout - _TIMEOUT_BUFFER_SECS
  | E           TypeError: unsupported operand type(s) for -: 'object' and 'float'
  |  
  | /usr/local/lib/python3.9/site-packages/google/cloud/bigquery/job/query.py:1329: TypeError

Thanks!