juju-core; default configuration value of ""

[James Page]

Hi All

A couple of days ago I noticed a change in behaviour for default string 
configuration values of "" in juju-core when compared to pyjuju.

Example config:

options:
   database:
     default: ""
     type: string
     description: empty string
   test_two:
     type: string
     description: no default string

Under pyjuju:

config-get --format=json database
""
config-get --format=json test_two
null

Under juju-core:

config-get --format=json database
null
config-get --format=json test_two
null

Specifically this breaks the postgresql charm on juju-core; I've raised 
a bug (see [0]) to which the juju-core team have responded; I prefer the 
proposed new behaviour (its in effect what I do in the charmn helpers I 
have written) but I appreciate that this will probably have impact on a 
large number of charms; so I'd like to throw this open to the list for 
further discussion.

Thoughts?

Cheers

James

[0] https://bugs.launchpad.net/juju-core/+bug/1192706


-- 
James Page
Ubuntu Core Developer
Debian Maintainer
james.page at ubuntu.com