Pre-transition triggers can optionally be fired whenever
a transition link is clicked, but before the transition form is shown.
In this way, a script can verify the constraints, before the user
spends time filling out the form, only to find the transition was
not permissible.
This function is a replacement for older TRELATIONs. Verify triggers
continue to fire as part of a transition, after the form is filled.
Marking them as verify only means that they are fired before the transition
form. However, they fire during a transition as usual.
Pre-transition triggers must be explicitly marked as being verify
triggers using the verify: prefix:
verify: bsf verifiy_associated_task_states.js completed
Note the following restrictions:
- verify: can be used only on pre-transition triggers.
If used on any other triggers, the prefix is silently ignored.
- verify: cannot be used with async:,
as the prefixes are mutually exclusive. Verify is inherently a synchronous
operation. If both are specified, only the first is recognized. The
second is considered the executable name.