CRM-21564: Change from using exec to WP_CLI::Launch

[TBSliver]

exec does not seem to be available on all systems. Also makes the code
more consistent for running external processes.

This was discussed in the CiviCRM chat in the wordpress channel about a month ago, have finally got around to pushing this PR

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• CRM-21564: Changing from using exec to WP_CLI::Launch

[kcristiano]

@TBSliver This looks like a good improvement. Thank you for the patch. I am away, but will test next week.

It would be great if you can log an issue in our Jira at https://issues.civicrm.org so we can track this in the changelog as well.

[TBSliver]

@kcristiano have just signed up for a Jira account (well, a CiviCRM account atleast) but have to wait for authorisation for it... So cant create a ticket for this, or the other issue I pushed (#120) :(

[mlutfy]

Hi @TBSliver, your account is now active.

[kcristiano]

Thanks @TBSliver I have tested this and it works. This looks ready to merge once we have a JIRA issue to reference.

[TBSliver]

Jesus I sometimes hate Jira ticket creation... thats some epic form. @kcristiano https://issues.civicrm.org/jira/browse/CRM-21564

[kcristiano]

@colemanw I am OK with merging this, but is there anyway to update the PR to include the JIRA issue for the release notes? cc @agh1

[TBSliver]

@kcristiano modified the title a while ago, hope this can be merged soon :)

[kcristiano]

@totten any chance you could give this a look and merge? This is an improvement we should have as soon as practical

[TBSliver]

@totten Any chance that this can get merged soon, as its now missed atleast 3 patch versions of Civi... and means that upgrades doesnt work on some deployments...

[christianwach]

@totten I agree with @TBSliver - with the caveat that the WPCLI docs suggest running the command through Utils\esc_cmd() first. See: https://make.wordpress.org/cli/handbook/internal-api/wp-cli-launch/#notes

[colemanw]

Merging based on positive reviews and feedback. Reading the code and referring to the WP_CLI documentation this looks like a sensible change.