Clearing execution time limit does not work

[MetRonnie]

Description

Clearing the execution time limit either by editing flow.cylc and reloading, or by broadcast/edit-runtime, does not work. The original execution time limit is maintained.

Reproducible Example

# flow.cylc
[scheduling]
    cycling mode = integer
    [[graph]]
        R1 = a
[runtime]
    [[a]]
        script = sleep 10
        execution time limit = PT1S

$ cylc play workflow

Wait for task to fail.

     [[a]]
         script = sleep 10
-        execution time limit = PT1S

$ cylc reload workflow
$ cylc trigger workflow//1/a

Expected Behaviour

The task should succeed now after 10s, but it still fails after 1s

[wxtim]

I have successfully reproduced, although it took a bit of work. It's worth noting that using the example given might result in a flaky functional test because having a very short ETL may result in an appearance of submission failure, because the ETL can be evaluated before the submission completes.

I was getting an apparent submission, followed by a submission failure on polling the task!

[wxtim]

I think I have it - execution time limit = None is entirely valid but this code assumes that it isn't:

        with suppress(TypeError):
            itask.summary[self.KEY_EXECUTE_TIME_LIMIT] = float(
                rtconfig['execution time limit']
            )

[oliver-sanders]

Closed by #5902