pylint: Instance of 'SubscriberClient' has no 'subscription_path' member

[dinvlad]

Environment details

• OS type and version: macOS Mojave 10.14.6
• Python version: python --version 3.7.7
• pip version: pip --version 20.0.2
• google-cloud-pubsub version: pip show google-cloud-pubsub 1.4.2

Steps to reproduce

1. Use the stock subscription example from https://github.com/googleapis/python-pubsub/blob/master/docs/subscriber/index.rst
2. Running pylint on it results in:

E1101: Instance of 'SubscriberClient' has no 'subscription_path' member (no-member)

Code example

from google.cloud import pubsub
subscriber = pubsub.SubscriberClient()

sub_path = subscriber.subscription_path(PROJECT, SUBSCRIPTION)

Stack trace

N/A

[dinvlad]

Might be related to googleapis/google-cloud-python#11865

[anguillanneuf]

@dinvlad Thanks for your question.

subscription_path is defined in cloud/pubsub_v1/gapic/subscriber_client.py:

python-pubsub/google/cloud/pubsub_v1/gapic/subscriber_client.py

Lines 109 to 116 in 21e761e

	@classmethod
	def subscription_path(cls, project, subscription):
	"""Return a fully-qualified subscription string."""
	return google.api_core.path_template.expand(
	"projects/{project}/subscriptions/{subscription}",
	project=project,
	subscription=subscription,
	)

This method is being added in cloud/pubsub_v1/subscriber/client.py via the decorator:

python-pubsub/google/cloud/pubsub_v1/subscriber/client.py

Lines 43 to 44 in 21e761e

	@_gapic.add_methods(subscriber_client.SubscriberClient, blacklist=_BLACKLISTED_METHODS)
	class Client(object):

You should be able to see the method if you run dir(subscriber). Does this help?

[dinvlad]

I think the issue is the typings, not necessarily that the method is not there (as it is). So I'd like to re-open this if possible, since the way this method is wired currently makes it incompatible with pylint.

[dinvlad]

Specifically, unlike the subscribe() method, the subscription_path() method is not wired directly into https://github.com/googleapis/python-pubsub/blob/master/google/cloud/pubsub_v1/subscriber/client.py, but rather through the @_gapic annotation.. I'm not sure if this would be easy to fix?

[anguillanneuf]

@plamut @pradn Please mark this as a consideration for Pub/Sub v2.

@dinvlad We really should be compatible with pylint because of pylint's widespread usage 😞But for Version 1 of our library, this is probably not going to happen as it doesn't affect the functionality of the library. We are currently designing v2 - compatibility with third party tools will make into our considerations. Thank you again for raising it.

[dinvlad]

I see, thank you for explaining @anguillanneuf ! We'll keep this in mind.

As a workaround, we may probably switch to another linter for now - I think this library itself uses pep8 if I'm not mistaken?

[anguillanneuf]

No problem @dinvlad ! We use nox, which complies to PEP8, see the Contributing Guide.

[plamut]

@dinvlad The classes in gapic/ directory are auto-generated based on the .proto definitions, including the SubscriberClient class, and there is a manual layer on top of that - the Client class from subscriber/client.py.

In order to avoid code duplication and to prevent the manual and generated client classes going out of sync, methods from the auto-generated class need to be automatically injected into the manual layer through the @_gapic.add_methods decorator. It's not surprising that such dynamic magic confuses the static linter. It's also not something that can be easily fixed in the library itself.

Of course, littering the source with numerous # pylint: disable=no-member comments is not appealing, but fortunately pylint can be configured to ignore that with the --generated-members setting. If you can stick to a common name for subscriber instances in your app, writing a regex that matches method invocations on them should do the trick.

Would that be feasible for your case?

[nicpreuss]

@anguillanneuf just ran into the same issue and found out this thread....I was wondering if there is any update on a release of the v2 allowing the fix to work with pylint?

[anguillanneuf]

@nicpreuss On v2 there isn't. But thank you for raising it so it stays on our radar.

[g2github]

I'm having this same issue, but am not clear what the "fix" is. How do I get past this error?