Removing strict type-validation for string/int type configuration options (None is good!)

Charles Butler charles.butler at
Mon Feb 10 14:54:59 UTC 2014

+1 to this. Null's or NoneType in configs will be a big help

On Mon, Feb 10, 2014 at 9:49 AM, Marco Ceppi <marco.ceppi at>wrote:

> Hi all,
> Currently, one of the proof requirements within charm-tools is that all
> configuration options must have a default key with a matching type value
> for that key.
> Most notably, some charms omit the default key and use strict None/NULL
> checking within the charm.
> In order to statisfy this proof rule, which is currently a WARNING level
> (meaning it does not interrupt juju operation, but can affect tools within
> the ecosystem), we've taken to adding `default: ""` to these missing keys.
> The reason being we had no way previously to set a None/NULL type value via
> the command line.
> Given that we now have the ability to do so via `juju unset` I'd like to
> propose we drop the requirement of having strict type checking and allow
> None/NULL as a valid configuration default for both string and int types
> (but not bool). In doing so we will still require you have a default: key
> present but it set to an appropriate value of either a value of the type
> the configuration is OR None/NULL[0]
> A WARNING will still be raised if no default key is present or if the
> default key is not the type the configuration option expects (and in the
> case of string or int, also not NULL/None)
>  Looking for some +1's or feedback on this policy change, hoping to get
> it released in the next version of charm-tools.
> Thanks,
> Marco Ceppi
> [0]:
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