Families, inheritance and GUI interaction

[TomekTrzeciak]

Describe exactly what you would like to see in an upcoming release

Task families play multiple roles in Cylc. They are used for (multiple) inheritance of settings, but also for task grouping in GUIs, graphs, queue and clock-trigger assignments, cylc commands, etc. Using the leading family inheritance for task grouping in GUIs is problematic, though. Consider the following example:

[runtime]
  [[FOO]]
  [[BAR]]
    inherit = FOO
  [[BAZ]]
    inherit = None, FOO

FOO will show up in GUI as a level of task grouping with BAR underneath, but selecting this group and, say, succeeding it will also succeed BAZ task due to inheritance, even though it was not part of the selection.

If leading (first) and secondary families formed disjoint sets, however, the above situation would be impossible. My suggestion would be to check for this condition during suite validation and issue a warning in Cylc 7.8.x and treat it as an error in Cylc 8+.

Additional context

Mentioned in #2701 (comment)

[sadielbartholomew]

I think this is discussed at least to some extent in #2570.

[hjoliver]

Good spotting @sadielbartholomew. This is technically a duplicate of that issue but I'll close the other one as superseded, as this expresses the problem more clearly [actually the other one is pretty clear, so let's move the discussion there @TomekTrzeciak].

[hjoliver]

Closing as duplicate.