Clarify lack of route time interval inheritance in docs

[gebn]

The <route> docs state optional configuration parameters are inherited from its parent node if not set. active_time_intervals and mute_time_intervals are currently copied as part of RouteOps, however they are then overwritten without the nil check that guards other parameters, removing the inheritance. Is this intentional?

The effect is a parent will not implicitly mute its children, e.g. given the following, a and b will still receive every alert all the time:

...
route:
  receiver: default
  routes:
  - routes:
    - receiver: a
      continue: true
    - receiver: b
    mute_time_intervals:
    - everyday
time_intervals:
- name: everyday
  time_intervals:
  - weekdays:
    - sunday:saturday

This tripped us up, as we wanted to notify two receivers with the same mute condition, and the only way to do this is to move the mute down into each child, e.g.

route:
  receiver: default
  routes:
  - routes:
    - receiver: a
      mute_time_intervals:
      - everyday
      continue: true
    - receiver: b
      mute_time_intervals:
      - everyday

If this is intended behaviour, I think it's worth making more explicit in the docs. I'm happy to submit a PR on confirmation.

[jmaixl]

Echoing this bug/feature request. I was just tripped up on this as well which forces me to duplicate routes in the routing tree.

[benridley]

This is not intentional. I've opened PR #3538 to address it, thanks for opening this!