Juju GUI handling of empty config breaks promulgated charms

[Stuart Bishop]

On 21 February 2017 at 00:40, Merlijn Sebrechts
<merlijn.sebrechts at gmail.com> wrote:
> Deploying cassandra with the GUI. Cassandra installation will fail with the
> following error.
>
> KeyError: 'http_proxy'
>
>
> The Cassandra charm expects config['http_proxy'] to return an empty string.
> This is what happens when deploying Cassandra using the CLI. However,
> config_get crashes because the config isn't set. running config-get in the
> hooks context shows that the http_proxy config value just isn't set.
>
> https://github.com/juju/juju-gui/issues/2486

I've made a new release using a newer charm-helpers. According to the
issue comments it should work around the problem.

I have no idea why Juju would be changing the empty string to null,
specially as I'm told from Juju's pov null is an invalid value for a
string and why setting a config value's default to null is a lint
error. But that contradicts the documentation for 'config-get --all',
which explicitly calls out config settings with non-null defaults. So
maybe this changed with 2.0, but there is some old code that missed
being updated?

-- 
Stuart Bishop <stuart.bishop at canonical.com>