tui: expand cycles/families in mutations to the visible selection

[oliver-sanders]

See #4238 (review)

UI sibling: cylc/cylc-ui#686

Task pool commands (e.g. cylc hold) can only apply pattern matching to the n=0 window. This means that cylc hold <family>.<cycle> or cylc hold '*.<cycle>' don't work if <cycle> is not in the n=0 window.

The practical upshot of this is if you try to hold a family or cycle of tasks in Tui that are in the n>0 window, then nothing happens.

To get around this problem we should expand the cycle/family to the full list of tasks visible in the UI.

[MetRonnie]

As it stands in #4238, <family>.<cycle> does work for tasks outside the n=0 window (provided the task exists at the cycle point in the graph)

[oliver-sanders]

Same for *.<cycle>, it's that this doesn't work outside the n=0 window (by design) that's the problem.

For example:

• 1
  • A
    • a (n=0)
    • b (n=1)
    • c (n=2 - not yet visible in the UI)

In this case Tui would show tasks a.1, a.2, however, attempting to hold either the cycle or family would only hold a.0 because that is the only task in the n=0 window.

cylc hold 'A.1'  # holds a.1
cylc hold '*.1'  # holds a.1

Because Tui knows what it's displaying it should issue a mutation that represents what the user is seeing (i.e. a.1, a.2 rather than 1.* or A.1). I think this is a nicer implementation in general, it isolates the user from changes which occur between the issue of the command in Tui and the command being processed in the workflow ensuring the principle of least surprise is maintained.

[oliver-sanders]

Adding the bug label as this is likely to cause confusion.

[hjoliver]

Documented deficiency, before implementation.