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pythonoopautocompletepycharm
Mark Harrison
Mark Harrison

Reputation: 304434

PyCharm: specifying type of returned variable?

How do I make PyCharm understand completions for a returned variable?

As per https://www.jetbrains.com/help/pycharm/5.0/type-hinting-in-pycharm.html

I'm asserting the type of a variable, but not getting any completions.

import boto.kinesis
x = boto.kinesis.connect_to_region("us-west-2")
assert isinstance(x, boto.kinesis.layer1.KinesisConnection)

foo = x.    <--- not getting completions here

enter image description here

Python 2,7, PyCharm Community Edition 2016.1.2

Upvotes: 1

Views: 270

Answers (2)

Mark Harrison
Mark Harrison

Reputation: 304434

(PyCharm Developer replies, via JetBrains support)

As @alexce noted the underlying problem is that PyCharm fails to resolve boto.kinesis.layer1 reference and hence symbol to boto.kinesis.layer1.KinesisConnection can't be resolved too.

Normally you can't refer to submodules of a package this way (without importing them explicitly). If PyCharm allowed it, there would be tons of false negative errors when one forgets to add necessary import statement. But because situations like that are quite common, we look through boto/kinesis/__init__.py trying to find some indication that sys.modules['boto.kinesis'] might already contain the attribute layer1.

Anything of the following would do:

from boto.kinesis import layer1
from . import layer1
from boto.kinesis.layer1 import KinesisConnection
import boto.kinesis.layer1
'layer1' in __all__

In fact __init__.py indeed contains the third of these import statements, but inside a function:

def regions():
    ...
    from boto.kinesis.layer1 import KinesisConnection
    ...

Since we can't guarantee statically that this function is called at runtime, we have nothing more to do other than warn about the unresolved reference in the editor.

Upvotes: 1

alecxe
alecxe

Reputation: 473763

This is related to Cannot find reference 'xxx' in __init__.py - Python / Pycharm and the fact that there is no __all__ defined inside the __init__.py inside the boto.kinesis package.

Importing the KinesisConnection directly from boto.kinesis.layer1 made it work for me:

import boto.kinesis
from boto.kinesis.layer1 import KinesisConnection

x = boto.kinesis.connect_to_region("us-west-2")
assert isinstance(x, KinesisConnection)

enter image description here

You can also import it and add a type hint into the comments:

import boto.kinesis
from boto.kinesis.layer1 import KinesisConnection

x = boto.kinesis.connect_to_region("us-west-2")  # type: KinesisConnection

enter image description here

Upvotes: 1

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