Horizon displays an error message on an empty instances list page

[Vadym Markov]

The following error is observed in the Horizon log:
Unable to connect to Neutron: 'frozenset' object has no attribute '_getitem_'

The error happens on the network_list requests when the parameter list is too long.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/653675
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=36515b38b2ab990aa16e14e9a410b710df661652
Submitter: Zuul
Branch: master

commit 36515b38b2ab990aa16e14e9a410b710df661652
Author: Pavlo Shchelokovskyy <email address hidden>
Date: Thu Apr 18 10:08:44 2019 +0300

    Do not try to access sets by index

    code in neutron api in some circumstances tries to access
    a set or a frozenset by index, which does not work.
    In particular it may manifest as

    Unable to connect to Neutron: 'frozenset' object has
    no attribute '__getitem__'

    error in the horizon.log when opening an empty instances list page.

    Convert to list instead, and skip conversion for `collections.Sequence`
    objects only that support all the methods used for this object
    further in this method.

    Closes-bug: #1825961
    Change-Id: I141a28d96f71c06a1ebe44d7067ccf4609e22db6

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/horizon 16.0.0.0b2 development milestone.