--version-check default should be explicitly "off"

[Daniel Nichter]

[12:30pm] Daniel: brian|lunch: i just noticed optional_value. it needs to be reverted. optional values are not something we want to do because it confuses the issue. there only 3 types of options: off unless specified (e.g. --version), negatable (on unless negated, e.g. --no-check-slave for --[no]check-slave), then options with values. an optional value crosses the line between the previous three and is not inline with the rest of the tools' options.

[12:30pm] Daniel: --version-check just needs to be type: string; default: https then docu possible values are https, and http

[Daniel Nichter (daniel-nichter)]

Here's a solution:

type: string

Possible values: auto, http, https, off*

Right now, with no default value, the feature is effectively off because if ( $o->get('version-check') ) will be false. But in the future we're going to change that default to either auto or https. Auto means "try https, if that fails, try http, else give up." Off means off, which will allow users to --version-check off when we set the default to auto or https.

* I thought of maybe "disable(d)" instead of "off", but "off" is a lot shorter; also "none" but that doesn't seem to make as much sense as "off".

[Daniel Nichter (daniel-nichter)]

Maybe we should keep it simple and do default: off right now, else users may ask, "it's not off, so what is it?" default: off is crystal clear. Then we can still my $vc = $o->get('v-c') if ( $vc ne 'off' ) ...

[Daniel Nichter (daniel-nichter)]

Changed bug title to make it a little more meaningful for users in the Changelog, i.e. that the default has changed, though the functionality has not changed. The real technical work here was reverting changes that introduced options with optional values, which is not something we want to do.

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PT-335