outputs: Transitory message tag appearance

[wxtim]

Describe the bug
When triggering a second task with a cylc message outputs the output shows up only briefly in the tree view until/unless page refreshed:

Release version(s) and/or repository branch(es) affected?
Found when checking that #1108 fixed #838.

Steps to reproduce the bug
Using workflow

[scheduler]
    allow implicit tasks = True

[scheduling]
    initial cycle point = 1000
    final cycle point = 1003
    [[graph]]
        P1Y = foo => bar

[runtime]
    [[foo]]
        script = """
            echo $CYLC_TASK_SUBMIT_NUMBER
            if [[ $CYLC_TASK_SUBMIT_NUMBER -eq 1 ]]; then
                cylc message -- loscil
                false
            elif [[ $CYLC_TASK_SUBMIT_NUMBER -eq 2 ]]; then
                cylc message -- biosphere
                false
            else
                cylc message -- gas
            fi
        """

run workflow. Re trigger task foo.

Expected behavior

Screenshots

Additional context

Pull requests welcome!
This is an Open Source project - please consider contributing a bug fix
yourself (please read CONTRIBUTING.md before starting any work though).

[oliver-sanders]

Have managed to reproduce.

The root cause of this issue is the way we handle lists in deltas.

1. Some fields such as childTasks send the entire field for each update.
2. Other fields such as messages send only the newly-added items.

The ui data store assumes (1) since otherwise it would not be possible for items to be removed from childTasks, only added.

[oliver-sanders]

Evidence extracted from the deltas...

First we get the messages biosphere and started:

{
	"jobs": [
		{
			"id": "~osanders/ambient//10020101T0000Z/foo/02",
			"startedTime": "2022-11-23T14:41:59Z",
			"state": "running",
			"messages": [
				"biosphere",
				"started"
			],
			"taskProxy": { ... },
			"__typename": "Job"
		}
	]
}

Then later we just get the message failed/ERR, the earlier messages having been removed:

{
	"jobs": [
		{
			"id": "~osanders/ambient//10020101T0000Z/foo/02",
			"finishedTime": "2022-11-23T14:42:01Z",
			"state": "failed",
			"messages": [
				"failed/ERR"
			],
			"taskProxy": { ... },
			"__typename": "Job"
		}
	]
}

[oliver-sanders]

We could "append" new messages rather than overwriting the entire list, however, this would require maintaining a list of fields for which the merging rules differ at the UI end.

[dwsutherland]

PR up:
cylc/cylc-flow#5240

have tested it in graphiql, seems to work.

[dwsutherland]

From Element:

Actually childTasks on FamilyProxy isn't the whole thing either (in the delta), however, an argument default for that subfield is deltaStore: false:

    child_tasks = graphene.List(
        TaskProxy,
        description="""Descendant task proxies.""",
        args=PROXY_ARGS,
        strip_null=STRIP_NULL_DEFAULT,
        delta_store=DELTA_STORE_DEFAULT,
        delta_type=DELTA_TYPE_DEFAULT,
        resolver=get_nodes_by_ids)

so the field resolver pulls from the data-store not the delta-store...

So subfield lists with ID lookups can be configured (in the query args) to do either behavior.

[oliver-sanders]

Closed by cylc/cylc-flow#5240