Error passing 'fields' to pubsub GET API for subscription

[tseaver]

$ tox -e regression --notest
GLOB sdist-make: /home/tseaver/projects/agendaless/Google/src/gcloud-python/setup.py
regression inst-nodeps: /home/tseaver/projects/agendaless/Google/src/gcloud-python/.tox/dist/gcloud-0.4.3.zip
___________________________________ summary ____________________________________
  regression: skipped tests
  congratulations :)
$ .tox/regression/bin/python regression/run_regression.py --package=pubsub
test_create_subscription (pubsub.TestPubsub) ... ERROR
test_create_topic (pubsub.TestPubsub) ... ok
test_list_subscriptions (pubsub.TestPubsub) ... ok
test_list_topics (pubsub.TestPubsub) ... ok
test_message_pull_mode_e2e (pubsub.TestPubsub) ... ERROR

ERROR: test_create_subscription (pubsub.TestPubsub)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/tseaver/projects/agendaless/Google/src/gcloud-python/regression/pubsub.py", line 74, in test_create_subscription
    self.assertFalse(subscription.exists())
  File "/home/tseaver/projects/agendaless/Google/src/gcloud-python/.tox/regression/lib/python2.7/site-packages/gcloud/pubsub/subscription.py", line 112, in exists
    query_params={'fields': 'name'})
  File "/home/tseaver/projects/agendaless/Google/src/gcloud-python/.tox/regression/lib/python2.7/site-packages/gcloud/connection.py", line 293, in api_request
    raise make_exception(response, content)
gcloud.exceptions.BadRequest: 400 Invalid JSON payload received. Unknown name "fields": Cannot bind query parameter.

I omitted a similar failure in another test: both are for a call to subscription.exists() where the expected value is False.

@dhermes this is the one I was working around in #794

@jgeewax maybe tag w/ "google bug"?

[dhermes]

Whoa! @tmatsuo note that fields is in the discovery doc, but does not actually work when used.

@tseaver Shall we "fix" be re-implementing your previous commit? (PS Good thing exception handling is finally working the way we want :))

[tseaver]

Caused breakage in regression tests on master:

https://travis-ci.org/GoogleCloudPlatform/gcloud-python/builds/57382647

Interestingly, the second failure I saw does not appear there. #heisenbug

[tseaver]

It would be nice to have confirmation that fields is not expected to be passed for non-existing subscriptions. @tmatsuo can you comment?

[tmatsuo]

Actually it is the first time I'm aware of the fields query parameter.
@tseaver
Let me confirm, does this succeed with existing subscription, and fail with non-existing subscriptions?

[tseaver]

@tmatsuo I just tweaked our regression test to avoid the call for non-existing subscription, and saw the same failure for an existing subscription.

[tmatsuo]

I think this is a bug within the new API infrastructure. I'll file a bug internally.

[tseaver]

I can provoke the 400 by supplying name in the fields input on the try it page

[tmatsuo]

Thanks! Filed a bug with an id: 20091445 internally

[tmatsuo]

I got a response.

"""
Could you try "$fields" instead?
"""

Actually I don't like the answer, but could you try it as suggested, just to see if it works?

[tseaver]

Using {"$fields": "name"} as query_params prevents the 400.

[tmatsuo]

Thanks for confirming.

JFYI, if the fields -> $fields change is an official thing, we still need to fix bunch of things.

• API explorer shows "fields" query param and there is no way to override it.
• Documentations need to be updated
  • https://developers.google.com/discovery/v1/using
  • https://developers.google.com/discovery/v1/parameters

Do you have any opinions about it?