Action trigger event errors can cause unrelated events to fail

[Jeff Davis]

EG 2.12.1

If an event fails while reacting, the failure can cascade, causing other, unrelated events to fail if they use the same open-ils.trigger drone.

We had a misconfigured action trigger event definition: the template was written as if it was a grouped event (it contains stuff like "target.0"), but the event def had no group_field value. As a result, the event failed with an error message like "Error processing Trigger template: undef error - No field by the name 0 in Fieldmapper::action::circulation!"

Subsequently, the same drone process was used to run other events for totally unrelated event defs -- specifically, ungrouped MarkItemLost events which have no template. These subsequent events failed with errors like "Event reacting failed with No field by the name 0 in Fieldmapper::action::circulation!" Note that this is the same error message as the initial failure. It's as if the initial failure produces an evt object which sticks around when the drone processes subsequent events.

It is highly undesirable for a misconfigured event def to cause problems for other events.

[Jeff Davis (jdavis-sitka)]

Previous discussion in IRC:

http://irc.evergreen-ils.org/evergreen/2017-09-19#i_324837

http://irc.evergreen-ils.org/evergreen/2018-01-04#i_340132