Hello! When I

merge

two task results together in a single one, the merge is supposed to return the first "real" result. What is considered a "real" result? It seems that only

None

is considered a non-real result. I would have expected that

NoResult

results would also be skipped, but this is not the case. Is this intended? Example in thread.

@Roy I am not sure this is the right implementation of

merge

. It is traditionally used after an

ifelse

or

switch

where the first param is the result of the true branch and the second param is a result of the false branch.

Ah okay. It seems like tasks that are

skipped

will not be considered in the merge, even though it may have been run. The example above is a simplification of what I am trying to do. I have two branches, but one of them may manually raise a

SKIP

signal that contains a

result

. In that case, both

merge

tasks are skipped and the result is

None

. Updated example:

from prefect import Flow, task
from prefect.engine import signals
from prefect.tasks.control_flow import case, merge

@task
def condition():
    return True

@task
def get_value():
    if file_exists("..."):
        value = load_file("...")
        raise signals.SKIP("Nothing to do here.", result=value)
    return compute_result("...")

@task
def false_task():
    return 5

with Flow(name="flow") as flow:
    cond = condition()
    with case(cond, True):
        res_t = get_value()

    with case(cond, False):
        res_f = false_task()

    res = merge(res_t, res_f)

state = flow.run()

print(state.result[res].result)

I expected this to return

value

, but the

merge

ignores this

skipped

task's

result

.