generated default List ConfigType ignores bounds

[Brian Rosmaita]

The List ConfigType has a 'bounds' option to indicate whether brackets are required when the value is specified. The generated default value, however, does not pay attention to the 'bounds' option, and as a result the sample output is confusing.

For example, glance/common/config.py contains the following option definition:
    cfg.ListOpt('enabled_import_methods',
                item_type=cfg.types.String(quotes=True),
                bounds=True,
                default=['glance-direct', 'web-download'],
                help=_("""
List of enabled Image Import Methods
Both 'glance-direct' and 'web-download' are enabled by default.
Related options:
    * [DEFAULT]/node_staging_uri
    * [DEFAULT]/enable_image_import""")),

This shows up in the generated file like this:

#
# List of enabled Image Import Methods
#
# Both 'glance-direct' and 'web-download' are enabled by default.
#
# Related options:
# * [DEFAULT]/node_staging_uri
# * [DEFAULT]/enable_image_import (list value)
#enabled_import_methods = glance-direct,web-download

If the operator uncomments this setting, a ValueError('Value should start with "["') is raised when the config file is loaded. It would be better if the default value displayed respected the 'bounds' setting, given that the reader of the config file has no way to know that bounds are required without reading the code (or by trial and error).

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/560716

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/560716
Committed: https://git.openstack.org/cgit/openstack/oslo.config/commit/?id=a69701c495947a2bbe618e71e20d6203977a6943
Submitter: Zuul
Branch: master

commit a69701c495947a2bbe618e71e20d6203977a6943
Author: Brian Rosmaita <email address hidden>
Date: Wed Apr 11 22:46:33 2018 -0400

    Make List option format bounds-sensitive

    The List ConfigType has a boolean 'bounds' option that indicates
    whether the value must be enclosed in brackets. This patch modifies
    the List formatter so that when bounds=True the output is displayed
    in enclosing brackets.

    Change-Id: Ide3748e67d14191b6b33c97c7d8437e4888e61d5
    Closes-bug: #1763239

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/oslo.config 6.1.0 release.