fix: QueryJob.exception() *returns* the errors, not raises them

google/cloud/bigquery/job/query.py

@@ -989,19 +989,30 @@ def done(self, retry=DEFAULT_RETRY, timeout=None, reload=True):
 
         Returns:
             bool: True if the job is complete, False otherwise.
+
+        Raises:
+            google.api_core.exceptions,GoogleAPICallError:
+                If a non-retryable error ocurrs while reloading the job metadata,
+                or if too many retry attempts fail.
         """
         # Do not refresh if the state is already done, as the job will not
         # change once complete.
         is_done = self.state == _DONE_STATE
         if not reload or is_done:
             return is_done
 
-        self._reload_query_results(retry=retry, timeout=timeout)
-
         # If an explicit timeout is not given, fall back to the transport timeout
         # stored in _blocking_poll() in the process of polling for job completion.
         transport_timeout = timeout if timeout is not None else self._transport_timeout
 
+        try:
+            self._reload_query_results(retry=retry, timeout=transport_timeout)
+        except exceptions.GoogleAPIError:
+            # Reloading also updates error details on self, no need for an
+            # explicit self.set_exception() call.
+            self.reload(retry=retry, timeout=transport_timeout)
+            return self.state == _DONE_STATE
+
         # Only reload the job once we know the query is complete.
         # This will ensure that fields such as the destination table are
         # correctly populated.

tests/unit/job/test_query.py

@@ -16,6 +16,7 @@
 import copy
 import http
 import textwrap
+import types
 
 import freezegun
 from google.api_core import exceptions
@@ -356,6 +357,45 @@ def test_done_w_timeout_and_longer_internal_api_timeout(self):
         call_args = fake_reload.call_args
         self.assertAlmostEqual(call_args.kwargs.get("timeout"), expected_timeout)
 
+    def test_done_w_query_results_error(self):
+        client = _make_client(project=self.PROJECT)
+        bad_request_error = exceptions.BadRequest("Error in query")
+        client._get_query_results = mock.Mock(side_effect=bad_request_error)
+
+        resource = self._make_resource(ended=False)
+        job = self._get_target_class().from_api_repr(resource, client)
+        job._exception = None
+
+        def fake_reload(self, *args, **kwargs):
+            self._properties["status"]["state"] = "DONE"
+            self.set_exception(copy.copy(bad_request_error))
+
+        fake_reload_method = types.MethodType(fake_reload, job)
+
+        with mock.patch.object(job, "reload", new=fake_reload_method):
+            is_done = job.done()
+
+        assert is_done
+        assert isinstance(job._exception, exceptions.BadRequest)
+
+    def test_done_w_job_reload_error(self):
+        client = _make_client(project=self.PROJECT)
+        query_results = google.cloud.bigquery.query._QueryResults(
+            properties={
+                "jobComplete": True,
+                "jobReference": {"projectId": self.PROJECT, "jobId": "12345"},
+            }
+        )
+        client._get_query_results = mock.Mock(return_value=query_results)
+
+        resource = self._make_resource(ended=False)
+        job = self._get_target_class().from_api_repr(resource, client)
+        retry_error = exceptions.RetryError("Too many retries", cause=TimeoutError)
+        job.reload = mock.Mock(side_effect=retry_error)
+        job._exception = None
+
+        self.assertRaisesRegex(exceptions.RetryError, r"Too many retries", job.done)
+
     def test_query_plan(self):
         from google.cloud._helpers import _RFC3339_MICROS
         from google.cloud.bigquery.job import QueryPlanEntry