Move Rules integration code into a sub-module for accurate dependencies

We do not want to insist that the Rules module is a requirement, because it is not needed for Scheduler. The rules components are provided for those who want to use them, they are entirely optional. The executable Scheduler code which triggers the events is protected inside calls to "moduleExists('rules')" and this works fine when running the site.

There must be some way to avoid the errors you have found. I'll do some investigation.

Jonathan

Hi Morsok,
Thanks for the info, that is really helpful. Yes I had been thinking that a sub-module might solve the problem, but was not sure if there was a simpler way. But if the auto-loader will always detect the missing classes then it seems that a sub-module is the right solution.

I'll work on this, and hopefully it won't be too long before you get your alpha2 release :-)

Jonathan

I have moved all the Rules-related code out of the main module and into a sub-module scheduler_rules_integration. In summary, this involved:

1. create folder scheduler_rules_integration and add scheduler_rules_integration.info.yml
2. set the dependency on rules in this new .yml file
3. move .rules_defaults.inc and .rules.events.yml into this new module folder and rename
4. move four conditions and four action files into scheduler_rules_integration/src/Plugin
5. move six event files into scheduler_rules_integration/src/Event
6. changed the namespace of the conditions from Drupal\scheduler\Plugin\Condition to Drupal\scheduler_rules_integration\Plugin\Condition (but the internal id is not changed)
7. likewise for actions and events
8. create scheduler_rules_integration.module and move into it the Rules code from hook_node_presave() and hook_node_insert()
9. remove rules code from SchedulerManager.php and instead call a new function _scheduler_rules_integration_dispatch_cron_event() to invoke the cron events

If the Rules module is not enabled then scheduler_rules_integration cannot be enabled. This prevents the dependency errors as reported in this issue and in #2790471: When editing a block: Fatal error: Class 'Core\RulesConditionBase' not found

I have also tested each part manually and it all works OK. I have written tests to cover all the rules actions, conditions and events, before making this change, and checking it afterwards, and I am happy that it all works. However, uploading these tests does not currently work on drupal.org testbots - I have raised #2775519: Automated testing for 3rd-party modules integrating with Rules

@mikemccaffrey If it is possible for you to test this patch and see if your composer errors are corrected that would be very helpful.

Thanks morsok for the advice and thanks slasher13 for the review.
This is a good fix. Committed and done.

Unassigning