Ordering of charm config items

[sparkiegeek]

In my config.yaml, I carefully order items so that related config is next to each other and newer config keys which replace others are 'above' the deprecated ones.

However, when I look at the charm details page, the config items are seemingly randomly ordered.

I note that the Juju CLI and Juju GUI order the values asciibetically, which whilst not perfect, is at least understandable.

[hatched]

So it turns out that the GUI isn't sorting these values after all, but instead presenting them in the same order it's returned from the charmstore so I'm not sure why one api call is returning them sorted and another returning them as-is in the config.yaml.

[frankban]

I think this happens because internally, in both juju and the charm store, charm options are represented as a map (see [1]) which is an unordered collection. I think the charm store should be patched to be consistent with juju by reordering the fields alphabetically on the meta endpoint.

[1] https://github.com/juju/charm/blob/v6/config.go#L78

[frankban]

After further investigation, it seems that the charm store already sorts the options alphabetically (see [1]). So second guess is that it depends on how js and python decode a JSON map by default: js into an object in which fields ordering is accidentally kept, python into a dict which is unordered.
Quickest fix going forward is rendering the options in alphabetical order in the jinja template of the store front. On a more medium/long term, json schema options would solve this and other charm config related annoyances, like not having enums.

[1] https://api.jujucharms.com/charmstore/v5/~juju-gui/jujushell/meta/charm-config